Router Security Requirements Guide

Version

SRG-NET-000019-RTR-000002

Vuln IDs

V-55721

Rule IDs

SV-69975r2_rule

Information flow control regulates authorized information to travel within a network and between interconnected networks. Controlling the flow of network traffic is critical so it does not introduce any unacceptable risk to the network infrastructure or data. An example of a flow control restriction is blocking outside traffic claiming to be from within the organization. For most routers, internal information flow control is a product of system design.

Checks: C-56287r3_chk

Verify each router enforces approved authorizations for controlling the flow of information between interconnected networks in accordance with applicable policy. If the router does not enforce approved authorizations for controlling the flow of information between interconnected networks in accordance with applicable policy, this is a finding.

Fix: F-60591r1_fix

Configure the router to enforce approved authorizations for controlling the flow of information between interconnected networks in accordance with applicable policy.

The multicast router must be configured to disable Protocol Independent Multicast (PIM) on all interfaces that are not required to support multicast routing.

AC-4 - Medium - CCI-001414 - V-55723 - SV-69977r2_rule

RMF Control

AC-4

Severity

CCI

Version

SRG-NET-000019-RTR-000003

Vuln IDs

V-55723

Rule IDs

SV-69977r2_rule

If multicast traffic is forwarded beyond the intended boundary, it is possible that it can be intercepted by unauthorized or unintended personnel. Limiting where, within the network, a given multicast group's data is permitted to flow is an important first step in improving multicast security. A scope zone is an instance of a connected region of a given scope. Zones of the same scope cannot overlap while zones of a smaller scope will fit completely within a zone of a larger scope. For example, Admin-local scope is smaller than Site-local scope, so the administratively configured boundary fits within the bounds of a site. According to RFC 4007 IPv6 Scoped Address Architecture (section 5), scope zones are also required to be "convex from a routing perspective"; that is, packets routed within a zone must not pass through any links that are outside of the zone. This requirement forces each zone to be one contiguous island rather than a series of separate islands. As stated in the DoD IPv6 IA Guidance for MO3, "One should be able to identify all interfaces of a zone by drawing a closed loop on their network diagram, engulfing some routers and passing through some routers to include only some of their interfaces." Therefore, it is imperative that the network engineers have documented their multicast topology and thereby knows which interfaces are enabled for multicast. Once this is done, the zones can be scoped as required.

Checks: C-56289r2_chk

If IPv4 or IPv6 multicast routing is enabled, verify all interfaces enabled for PIM are documented in the network's multicast topology diagram. Review the router configuration to determine if multicast routing is enabled and which interfaces are enabled for PIM. If an interface is not required to support multicast routing and it is enabled, this is a finding.

Fix: F-60593r1_fix

Document all enabled interfaces for PIM in the network's multicast topology diagram. Disable support for PIM on interfaces that are not required to support it.

The multicast router must be configured to bind a Protocol Independent Multicast (PIM) neighbor filter to interfaces that have PIM enabled.

AC-4 - Medium - CCI-001414 - V-55727 - SV-69981r2_rule

RMF Control

AC-4

Severity

CCI

Version

SRG-NET-000019-RTR-000004

Vuln IDs

V-55727

Rule IDs

SV-69981r2_rule

PIM is a routing protocol used to build multicast distribution trees for forwarding multicast traffic across the network infrastructure. PIM traffic must be limited to only known PIM neighbors by configuring and binding a PIM neighbor filter to those interfaces that have PIM enabled. If a PIM neighbor filter is not applied to those interfaces that have PIM enabled, unauthorized routers can join the PIM domain, discover and use the rendezvous points, and also advertise their rendezvous points into the domain. This can result in a denial of service by traffic flooding or result in the unauthorized transfer of data.

Checks: C-56293r2_chk

This requirement is not applicable for the DoDIN Backbone. Review the multicast topology diagram and determine if router interfaces are enabled for IPv4 or IPv6 multicast routing. If the router is enabled for multicast routing, verify all interfaces enabled for PIM have a neighbor filter bound to the interface. The neighbor filter must only accept PIM control plane traffic from the documented PIM neighbors. If PIM neighbor filters are not bound to all interfaces that have PIM enabled, this is a finding.

Fix: F-60597r2_fix

This requirement is not applicable for the DoDIN Backbone. Configure neighbor filters to only accept PIM control plane traffic from documented PIM neighbors. Bind neighbor filters to all PIM enabled interfaces.

The multicast edge router must be configured to establish boundaries for administratively scoped multicast traffic.

AC-4 - Low - CCI-001414 - V-55729 - SV-69983r2_rule

RMF Control

AC-4

Severity

CCI

Version

SRG-NET-000019-RTR-000005

Vuln IDs

V-55729

Rule IDs

SV-69983r2_rule

If multicast traffic is forwarded beyond the intended boundary, it is possible that it can be intercepted by unauthorized or unintended personnel. Administrative scoped multicast addresses are locally assigned and are to be used exclusively by the enterprise network or enclave. Administrative scoped multicast traffic must not cross the enclave perimeter in either direction. Restricting multicast traffic makes it more difficult for a malicious user to access sensitive traffic. Admin-Local scope is encouraged for any multicast traffic within a network intended for network management, as well as for control plane traffic that must reach beyond link-local destinations.

Checks: C-56295r1_chk

Review the multicast topology diagram to determine if there are any documented Admin-Local (FFx4::/16), Site-Local (FFx5::/16), or Organization-Local (FFx8::/16) multicast boundaries for IPv6 traffic or any Local-Scope (239.255.0.0/16) boundaries for IPv4 traffic. Verify the appropriate boundaries are configured on the applicable multicast-enabled interfaces. If the appropriate boundaries are not configured on applicable multicast-enabled interfaces, this is a finding.

Fix: F-60599r1_fix

Configure the appropriate boundaries to contain packets addressed within the administratively scoped zone. Defined multicast addresses are FFx4::/16, FFx5::/16, FFx8::/16, and 239.255.0.0/16.

The router must be configured to have all inactive interfaces disabled.

AC-4 - Low - CCI-001414 - V-55731 - SV-69985r3_rule

RMF Control

AC-4

Severity

CCI

Version

SRG-NET-000019-RTR-000007

Vuln IDs

V-55731

Rule IDs

SV-69985r3_rule

An inactive interface is rarely monitored or controlled and may expose a network to an undetected attack on that interface. Unauthorized personnel with access to the communication facility could gain access to a router by connecting to a configured interface that is not in use. If an interface is no longer used, the configuration must be deleted and the interface disabled. For sub-interfaces, delete sub-interfaces that are on inactive interfaces and delete sub-interfaces that are themselves inactive. If the sub-interface is no longer necessary for authorized communications, it must be deleted.

Checks: C-56297r3_chk

Review the router configuration. If an interface is not being used but is configured or enabled, this is a finding.

Fix: F-60601r3_fix

Delete inactive sub-interfaces and disable and delete the configuration of any inactive ports on the router.

The perimeter router must be configured to not be a Border Gateway Protocol (BGP) peer to an alternate gateway service provider.

AC-4 - High - CCI-001414 - V-55733 - SV-69987r2_rule

RMF Control

AC-4

Severity

CCI

Version

SRG-NET-000019-RTR-000009

Vuln IDs

V-55733

Rule IDs

SV-69987r2_rule

The perimeter router will not use a routing protocol to advertise NIPRNet addresses to alternate gateways. Most ISPs use BGP to share route information with other autonomous systems, that is, any network under a different administrative control and policy than a local site. If BGP is configured on the perimeter router, no BGP neighbors will be defined to peer routers from an autonomous system (AS) belonging to any alternate gateway. The only allowable method is a static route to reach the alternate gateway.

Checks: C-56301r2_chk

This requirement is not applicable for the DoDIN Backbone. Review the configuration of the router connecting to the alternate gateway. Verify there are no BGP neighbors configured to the remote AS that belongs to the alternate gateway service provider. If there are BGP neighbors connecting the remote AS of the alternate gateway service provider, this is a finding.

Fix: F-60603r2_fix

This requirement is not applicable for the DoDIN Backbone. Configure a static route on the perimeter router to reach the AS of a router connecting to an alternate gateway.

The perimeter router must be configured to not redistribute static routes to an alternate gateway service provider into BGP or an IGP peering with the NIPRNet or to other autonomous systems.

AC-4 - Low - CCI-001414 - V-55735 - SV-69989r2_rule

RMF Control

AC-4

Severity

CCI

Version

SRG-NET-000019-RTR-000010

Vuln IDs

V-55735

Rule IDs

SV-69989r2_rule

If the static routes to the alternate gateway are being redistributed into an Exterior Gateway Protocol or Interior Gateway Protocol to a NIPRNet gateway, this could make traffic on NIPRNet flow to that particular router and not to the Internet Access Point routers. This could not only wreak havoc with traffic flows on NIPRNet, but it could overwhelm the connection from the router to the NIPRNet gateway(s) and also cause traffic destined for outside of NIPRNet to bypass the defenses of the Internet Access Points.

Checks: C-56303r3_chk

This requirement is not applicable for the DoDIN Backbone. Review the configuration of the route connecting to the alternate gateway. Verify that redistribution of static routes to the alternate gateway is not occurring. If the static routes to the alternate gateway are being redistributed into an Exterior Gateway Protocol or Interior Gateway Protocol to a NIPRNet gateway, this is a finding.

Fix: F-60607r2_fix

This requirement is not applicable for the DoDIN Backbone. Configure the router so that static routes are not redistributed to an alternate gateway into either an Exterior Gateway Protocol or Interior Gateway Protocol to the NIPRNet or to other autonomous systems.

The out-of-band management (OOBM) gateway router must be configured to have separate IGP instances for the managed network and management network.

AC-4 - Medium - CCI-001414 - V-55739 - SV-69993r2_rule

RMF Control

AC-4

Severity

CCI

Version

SRG-NET-000019-RTR-000011

Vuln IDs

V-55739

Rule IDs

SV-69993r2_rule

If the gateway router is not a dedicated device for the OOBM network, implementation of several safeguards for containment of management and production traffic boundaries must occur. Since the managed and management network are separate routing domains, configuration of separate Interior Gateway Protocol routing instances is critical on the router to segregate traffic from each network.

Checks: C-56305r2_chk

This requirement is not applicable for the DoDIN Backbone. Verify that the OOBM interface is an adjacency in the Interior Gateway Protocol routing domain for the management network. If the router does not enforce that Interior Gateway Protocol instances configured on the OOBM gateway router peer only with their own routing domain, this is a finding.

Fix: F-60609r2_fix

This requirement is not applicable for the DoDIN Backbone. Configure the router to enforce that Interior Gateway Protocol instances configured on the OOBM gateway router peer only with their own routing domain.

The out-of-band management (OOBM) gateway router must be configured to not redistribute routes between the management network routing domain and the managed network routing domain.

AC-4 - Medium - CCI-001414 - V-55741 - SV-69995r2_rule

RMF Control

AC-4

Severity

CCI

Version

SRG-NET-000019-RTR-000012

Vuln IDs

V-55741

Rule IDs

SV-69995r2_rule

If the gateway router is not a dedicated device for the OOBM network, several safeguards must be implemented for containment of management and production traffic boundaries; otherwise, it is possible that management traffic will not be separated from production traffic. Since the managed network and the management network are separate routing domains, separate Interior Gateway Protocol routing instances must be configured on the router, one for the managed network and one for the OOBM network. In addition, the routes from the two domains must not be redistributed to each other.

Checks: C-56307r2_chk

This requirement is not applicable for the DoDIN Backbone. Verify the Interior Gateway Protocol instance used for the managed network does not redistribute routes into the Interior Gateway Protocol instance used for the management network, and vice versa. If the Interior Gateway Protocol instance used for the managed network redistributes routes into the Interior Gateway Protocol instance used for the management network, or vice versa, this is a finding.

Fix: F-60613r2_fix

This requirement is not applicable for the DoDIN Backbone. Configure the Interior Gateway Protocol instance used for the managed network to prohibit redistribution of routes into the Interior Gateway Protocol instance used for the management network, and vice versa.

The multicast Rendezvous Point (RP) router must be configured to filter Protocol Independent Multicast (PIM) Register messages received from the Designated Router (DR) for any undesirable multicast groups and Bogon sources.

AC-4 - Low - CCI-001414 - V-55747 - SV-70001r2_rule

RMF Control

AC-4

Severity

CCI

Version

SRG-NET-000019-RTR-000013

Vuln IDs

V-55747

Rule IDs

SV-70001r2_rule

Real-time multicast traffic can entail multiple large flows of data. An attacker can flood a network segment with multicast packets, over-using the available bandwidth and thereby creating a denial-of-service (DoS) condition. Hence, it is imperative that register messages are accepted only for authorized multicast groups and sources.

Checks: C-56313r2_chk

Verify that the RP router is configured to filter PIM register messages. If the RP router peering with PIM-SM routers is not configured with a PIM import policy to block registration messages for any undesirable multicast groups and Bogon sources, this is a finding.

Fix: F-60617r2_fix

Configure RP routers to filter PIM register messages received from a multicast DR for any undesirable multicast groups or BOGON sources.

The multicast Rendezvous Point (RP) router must be configured to filter Protocol Independent Multicast (PIM) Join messages received from the Designated Router (DR) for any undesirable multicast groups.

AC-4 - Low - CCI-001414 - V-55749 - SV-70003r2_rule

RMF Control

AC-4

Severity

CCI

Version

SRG-NET-000019-RTR-000014

Vuln IDs

V-55749

Rule IDs

SV-70003r2_rule

Real-time multicast traffic can entail multiple large flows of data. An attacker can flood a network segment with multicast packets, over-using the available bandwidth and thereby creating a denial-of-service (DoS) condition. Hence, it is imperative that join messages are only accepted for authorized multicast groups.

Checks: C-56317r3_chk

Verify that the RP router is configured to filter PIM join messages for any reserved multicast groups. If the RP router peering with PIM-SM routers is not configured with a PIM import policy to block join messages for reserved and any undesirable multicast groups, this is a finding.

Fix: F-60621r2_fix

RP routers that are peering with customer PIM-SM routers must implement a PIM import policy to block join messages for reserved and any undesirable multicast groups.

The router must be configured to implement message authentication for all control plane protocols.

CM-6 - Medium - CCI-000366 - V-55757 - SV-70011r2_rule

RMF Control

CM-6

Severity

CCI

Version

SRG-NET-000025-RTR-000020

Vuln IDs

V-55757

Rule IDs

SV-70011r2_rule

Checks: C-56323r2_chk

Review the router configuration. For every protocol that affects the routing or forwarding tables (where information is exchanged between neighbors), verify that neighbor router authentication is enabled. If authentication is not enabled, this is a finding.

Fix: F-60627r1_fix

Configure authentication to be enabled for every protocol that affects the routing or forwarding tables.

The router must be configured to use keys with a duration not exceeding 180 days for authenticating routing protocol messages.

CM-6 - Medium - CCI-000366 - V-55759 - SV-70013r2_rule

RMF Control

CM-6

Severity

CCI

Version

SRG-NET-000025-RTR-000085

Vuln IDs

V-55759

Rule IDs

SV-70013r2_rule

If the keys used for routing protocol authentication are guessed, the malicious user could create havoc within the network by advertising incorrect routes and redirecting traffic. Some routing protocols allow the use of key chains for authentication. A key chain is a set of keys that is used in succession, with each having a lifetime of no more than 180 days. Changing the keys frequently reduces the risk of them eventually being guessed. Keys cannot be used during time periods for which they are not activated. If a time period occurs during which no key is activated, neighbor authentication cannot occur, and therefore routing updates will fail. Therefore, ensure that for a given key chain, key activation times overlap to avoid any period of time during which no key is activated.

Checks: C-56325r2_chk

This requirement is not applicable for the DoDIN Backbone. For each authenticated routing protocol session, review the configured key expiration dates. If any key has a lifetime of more than 180 days, this is a finding.

Fix: F-60629r3_fix

This requirement is not applicable for the DoDIN Backbone. For each authenticated routing protocol session, configure each key to have a lifetime of no more than 180 days.

The perimeter router must be configured to restrict it from accepting outbound IP packets that contain an illegitimate address in the source address field via egress filter or by enabling Unicast Reverse Path Forwarding (uRPF).

SC-5 - High - CCI-001094 - V-55761 - SV-70015r2_rule

RMF Control

SC-5

Severity

CCI

CCI-001094

Version

SRG-NET-000026-RTR-000031

Vuln IDs

V-55761

Rule IDs

SV-70015r2_rule

A compromised host in an enclave can be used by a malicious actor as a platform to launch cyber attacks on third parties. This is a common practice in "botnets", which are a collection of compromised computers using malware to attack (usually distributed denial of service [DDoS]) other computers or networks. DDoS attacks frequently leverage IP source address spoofing, in which packets with false source IP addresses send traffic to multiple hosts, which then send return traffic to the hosts with the IP addresses that were forged. This can generate significant, even massive, amounts of traffic. Therefore, protection measures to counteract IP source address spoofing must be taken. The router must not accept any outbound IP packets that contain an illegitimate address in the source address field by enabling uRPF strict mode or by implementing an egress access control list (ACL). uRPF provides an IP address spoof protection capability. When uRPF is enabled in strict mode, the packet must be received on the interface that the device would use to forward the return packet.

Checks: C-56327r3_chk

This requirement is not applicable for the DoDIN Backbone. Review the router configuration to verify uRPF or an egress filter has been configured on all internal interfaces to restrict the router from accepting outbound IP packets that contain an illegitimate address in the source address field. If uRPF or an egress filter to restrict the router from accepting outbound IP packets that contain an illegitimate address in the source address field has not been configured on all internal interfaces in an enclave, this is a finding.

Fix: F-60631r2_fix

This requirement is not applicable for the DoDIN Backbone. Configure the router to ensure that an egress filter or uRPF is configured to restrict the router from accepting any outbound IP packet that contains an external IP address in the source field.

The router must be configured to have all non-essential capabilities disabled.

CM-7 - Low - CCI-000381 - V-55763 - SV-70017r2_rule

RMF Control

CM-7

Severity

CCI

CCI-000381

Version

SRG-NET-000131-RTR-000035

Vuln IDs

V-55763

Rule IDs

SV-70017r2_rule

A compromised router introduces risk to the entire network infrastructure, as well as data resources that are accessible via the network. The perimeter defense has no oversight or control of attacks by malicious users within the network. Preventing network breaches from within is dependent on implementing a comprehensive defense-in-depth strategy, including securing each device connected to the network. This is accomplished by following and implementing all security guidance applicable for each node type. A fundamental step in securing each router is to enable only the capabilities required for operation.

Checks: C-56329r1_chk

Review the router configuration to determine if services or functions not required for operation, or not related to router functionality (e.g., DNS, email client or server, FTP server, or web server) are enabled. If unnecessary services and functions are enabled on the router, this is a finding.

Fix: F-60633r2_fix

Remove unneeded services and functions from the router. Removal is recommended because the service or function may be inadvertently enabled otherwise. However, if removal is not possible, disable the service or function.

The router must be configured to use encryption for routing protocol authentication.

IA-7 - Medium - CCI-000803 - V-55765 - SV-70019r2_rule

RMF Control

IA-7

Severity

CCI

CCI-000803

Version

SRG-NET-000168-RTR-000077

Vuln IDs

V-55765

Rule IDs

SV-70019r2_rule

A rogue router could send a fictitious routing update to convince a site's perimeter router to send traffic to an incorrect or even a rogue destination. This diverted traffic could be analyzed to learn confidential information about the site's network or used to disrupt the network's ability to communicate with other networks. This is known as a "traffic attraction attack" and is prevented by configuring neighbor router authentication for routing updates. However, using clear-text authentication provides little benefit since an attacker can intercept traffic and view the authentication key. This would allow the attacker to use the authentication key in an attack. This requirement applies to all IPv4 and IPv6 protocols that are used to exchange routing or packet forwarding information; this includes all Interior Gateway Protocols (such as OSPF, EIGRP, and IS-IS) and Exterior Gateway Protocols (such as BGP), MPLS-related protocols (such as LDP), and multicast-related protocols.

Checks: C-56331r2_chk

Review the router configuration. For every protocol that affects the routing or forwarding tables (where information is exchanged between neighbors), verify that neighbor router authentication is encrypting the authentication key. If authentication is not encrypting the authentication key, this is a finding.

Fix: F-60635r1_fix

Configure routing protocol authentication to encrypt the authentication key.

The router must be configured to authenticate all routing protocol messages using NIST-validated FIPS 140-2 message authentication code algorithm.

IA-7 - Medium - CCI-000803 - V-55767 - SV-70021r2_rule

RMF Control

IA-7

Severity

CCI

CCI-000803

Version

SRG-NET-000168-RTR-000078

Vuln IDs

V-55767

Rule IDs

SV-70021r2_rule

A rogue router could send a fictitious routing update to convince a site's perimeter router to send traffic to an incorrect or even a rogue destination. This diverted traffic could be analyzed to learn confidential information about the site's network or used to disrupt the network's ability to communicate with other networks. This is known as a "traffic attraction attack" and is prevented by configuring neighbor router authentication for routing updates. However, using clear-text authentication provides little benefit since an attacker can intercept traffic and view the authentication key. This would allow the attacker to use the authentication key in an attack. Since MD5 is vulnerable to "birthday" attacks and may be compromised, routing protocol authentication must use FIPS 140-2 validated algorithms and modules to encrypt the authentication key. This requirement applies to all IPv4 and IPv6 protocols that are used to exchange routing or packet forwarding information; this includes all Interior Gateway Protocols (such as OSPF, EIGRP, and IS-IS) and Exterior Gateway Protocols (such as BGP), MPLS-related protocols (such as LDP), and multicast-related protocols.

Checks: C-56333r3_chk

Review the router configuration to verify it is using a NIST-validated FIPS 140-2 message authentication code algorithm to authenticate routing protocol messages. If a NIST-validated FIPS 140-2 message authentication code algorithm is not being used to authenticate routing protocol messages, this is a finding.

Fix: F-60637r3_fix

Configure routing protocol authentication to use a NIST-validated FIPS 140-2 message authentication code algorithm.

The BGP router must be configured to enable the Generalized TTL Security Mechanism (GTSM).

SC-5 - Low - CCI-002385 - V-55769 - SV-70023r2_rule

RMF Control

SC-5

Severity

CCI

Version

SRG-NET-000191-RTR-000081

Vuln IDs

V-55769

Rule IDs

SV-70023r2_rule

As described in RFC 3682, GTSM is designed to protect a router's IP-based control plane from DoS attacks. Many attacks focused on CPU load and line-card overload can be prevented by implementing GTSM on all Exterior Border Gateway Protocol speaking routers. GTSM is based on the fact that the vast majority of control plane peering is established between adjacent routers; that is, the Exterior Border Gateway Protocol peers are either between connecting interfaces or between loopback interfaces. Since TTL spoofing is considered nearly impossible, a mechanism based on an expected TTL value provides a simple and reasonably robust defense from infrastructure attacks based on forged control plane traffic.

Checks: C-56335r2_chk

Review the router configuration. If the router is not configured to use GTSM for all Exterior Border Gateway Protocol peering sessions, this is a finding.

Fix: F-60639r2_fix

Configure all Exterior Border Gateway Protocol peering sessions to use GTSM.

The perimeter router must be configured to block all packets with any IP options.

SC-7 - Medium - CCI-002403 - V-55773 - SV-70027r2_rule

RMF Control

SC-7

Severity

CCI

Version

SRG-NET-000195-RTR-000084

Vuln IDs

V-55773

Rule IDs

SV-70027r2_rule

Packets with IP options are not fast switched and henceforth must be punted to the router processor. Hackers who initiate denial-of-service (DoS) attacks on routers commonly send large streams of packets with IP options. Dropping the packets with IP options reduces the load of IP options packets on the router. The end result is a reduction in the effects of the DoS attack on the router and on downstream routers.

Checks: C-56339r2_chk

This requirement is not applicable for the DoDIN Backbone. Review the router configuration to determine if it will block all packets with IP options. If the router is not configured to drop all packets with IP options, this is a finding.

Fix: F-60643r2_fix

This requirement is not applicable for the DoDIN Backbone. Configure the router to drop all packets with IP options.

The router must be configured to stop forwarding traffic upon the failure of the following actions: system initialization, shutdown, or system abort.

SC-24 - Medium - CCI-001190 - V-55779 - SV-70033r2_rule

RMF Control

SC-24

Severity

CCI

CCI-001190

Version

SRG-NET-000235-RTR-000114

Vuln IDs

V-55779

Rule IDs

SV-70033r2_rule

Failure to a known safe state helps prevent systems from failing to a state that may cause loss of data or unauthorized access to system resources. Routers that fail suddenly and with no incorporated failure state planning may leave the hosting system available but with a reduced security protection capability. Preserving information system state information also facilitates system restart and return to the operational mode of the organization with less disruption to mission-essential processes. If the router fails in an unsecure manner (open), unauthorized traffic originating externally to the enclave may enter, or the device may permit unauthorized information release. Fail secure is a condition achieved by employing information system mechanisms to ensure, in the event of a device initialization failure, a device shutdown failure, or an abort failure of the router, that it does not enter into an unsecure state where intended security properties no longer hold. If the device fails, it must not fail in a manner that will allow unauthorized access. If the router fails for any reason, it must stop forwarding traffic altogether or maintain the configured security policies. If the device stops forwarding traffic, maintaining network availability would be achieved through device redundancy. Since it is usually not possible to test this capability in a production environment, systems should either be validated in a testing environment or prior to installation. This requirement is usually a function of the design of the router component. Compliance can be verified by acceptance/validation processes or vendor attestation.

Checks: C-56345r3_chk

Verify the router stops forwarding traffic or maintains the configured security policies upon the failure of the following actions: system initialization, shutdown, or system abort. If the router does not stop forwarding traffic or maintain the configured security policies upon the failure of system initialization, shutdown, or system abort, this is a finding.

Fix: F-60649r2_fix

This is a capability that would be intrinsic to the router as a result of its development and may not be configurable. If it is a configurable option, configure the router to stop forwarding traffic or maintain the configured security policies upon the failure of the following actions: system initialization, shutdown, or system abort.

The router must be configured to protect against or limit the effects of denial-of-service (DoS) attacks by employing control plane protection.

SC-5 - Medium - CCI-002385 - V-55781 - SV-70035r2_rule

RMF Control

SC-5

Severity

CCI

Version

SRG-NET-000362-RTR-000110

Vuln IDs

V-55781

Rule IDs

SV-70035r2_rule

The Route Processor (RP) is critical to all network operations because it is the component used to build all forwarding paths for the data plane via control plane processes. It is also instrumental with ongoing network management functions that keep the routers and links available for providing network services. Any disruption to the RP or the control and management planes can result in mission-critical network outages. A DoS attack targeting the RP can result in excessive CPU and memory utilization. To maintain network stability and RP security, the router must be able to handle specific control plane and management plane traffic that is destined to the RP. In the past, one method of filtering was to use ingress filters on forwarding interfaces to filter both forwarding path and receiving path traffic. However, this method does not scale well as the number of interfaces grows and the size of the ingress filters grows. Control plane policing increases the security of routers and multilayer switches by protecting the RP from unnecessary or malicious traffic. Filtering and rate limiting the traffic flow of control plane packets can be implemented to protect routers against reconnaissance and DoS attacks, allowing the control plane to maintain packet forwarding and protocol states despite an attack or heavy load on the router or multilayer switch.

Checks: C-56347r1_chk

Determine whether control plane protection has been implemented on the device by verifying traffic types have been classified based on importance levels and a policy has been configured to filter and rate limit the traffic according to each class. If the router does not have control plane protection implemented, this is a finding.

Fix: F-60651r2_fix

Implement control plane protection by classifying traffic types based on importance and configure filters to restrict and rate limit the traffic directed to and processed by the RP according to each class.

The perimeter router must be configured to only allow incoming communications from authorized sources to be routed to authorized destinations.

SC-7 - Medium - CCI-002403 - V-55785 - SV-70039r2_rule

RMF Control

SC-7

Severity

CCI

Version

SRG-NET-000364-RTR-000109

Vuln IDs

V-55785

Rule IDs

SV-70039r2_rule

Unrestricted traffic may contain malicious traffic that poses a threat to an enclave or to other connected networks. Additionally, unrestricted traffic may transit a network, which uses bandwidth and other resources. Traffic can be restricted directly by an access control list (ACL), which is a firewall function, or by Policy Routing. Policy Routing is a technique used to make routing decisions based on a number of different criteria other than just the destination network, including source or destination network, source or destination address, source or destination port, protocol, packet size, and packet classification. This overrides the router's normal routing procedures used to control the specific paths of network traffic. It is normally used for traffic engineering but can also be used to meet security requirements; for example, traffic that is not allowed can be routed to the Null0 or discard interface. Policy Routing can also be used to control which prefixes appear in the routing table. This requirement is intended to allow network administrators the flexibility to use whatever technique is most effective.

Checks: C-56355r3_chk

This requirement is not applicable for the DoDIN Backbone. Review the router configuration to determine if the router allows only incoming communications from authorized sources to be routed to authorized destinations. If the router does not restrict incoming communications to allow only authorized sources and destinations, this is a finding.

Fix: F-60659r2_fix

This requirement is not applicable for the DoDIN Backbone. Configure the router to allow only incoming communications from authorized sources to be routed to authorized destinations.

The router must be configured to fail securely in the event of an operational failure.

SC-7 - Medium - CCI-001126 - V-55789 - SV-70043r2_rule

RMF Control

SC-7

Severity

CCI

CCI-001126

Version

SRG-NET-000365-RTR-000112

Vuln IDs

V-55789

Rule IDs

SV-70043r2_rule

If the router fails in an unsecure manner (open), unauthorized traffic originating externally to the enclave may enter or the device may permit unauthorized information release. Fail secure is a condition achieved by employing information system mechanisms to ensure, in the event of an operational failure of the router, that it does not enter into an unsecure state where intended security properties no longer hold. If the device fails, it must not fail in a manner that will allow unauthorized access. If the router fails for any reason, it must stop forwarding traffic altogether or maintain the configured security policies. If the device stops forwarding traffic, maintaining network availability would be achieved through device redundancy.

Checks: C-56357r2_chk

Review the documentation of the router or interview the System Administrator. Verify that the router fails securely in the event of an operational failure. If it cannot fail securely, this is a finding.

Fix: F-60661r2_fix

This is a capability that would be intrinsic to the router as a result of its development and may not be configurable. If it is a configurable option, configure the device to fail securely in the event of an operational failure.

The router must be configured to enforce approved authorizations for controlling the flow of information within the network based on organization-defined information flow control policies.

AC-4 - Medium - CCI-001368 - V-78209 - SV-92915r1_rule

RMF Control

AC-4

Severity

CCI

Version

SRG-NET-000018-RTR-000001

Vuln IDs

V-78209

Rule IDs

SV-92915r1_rule

Information flow control regulates where information is allowed to travel within a network and between interconnected networks. The flow of all network traffic must be monitored and controlled so it does not introduce any unacceptable risk to the network infrastructure or data. Information flow control policies and enforcement mechanisms are commonly employed by organizations to control the flow of information between designated sources and destinations (e.g., networks, individuals, and devices) within information systems. Enforcement occurs, for example, in boundary protection devices (e.g., gateways, routers, guards, encrypted tunnels, and firewalls) that employ rule sets or establish configuration settings that restrict information system services, provide a packet filtering capability based on header information, or provide a message filtering capability based on message content (e.g., implementing key word searches or using document characteristics).

Checks: C-77765r1_chk

This requirement is not applicable for the DoDIN Backbone. Review the router configuration to verify that access control lists (ACLs) and filters are configured to allow or deny traffic for specific source and destination addresses as well as ports and protocols. These filters should be applied inbound or outbound on the appropriate external and internal interfaces. If the router is not configured to enforce approved authorizations for controlling the flow of information within the network based on organization-defined information flow control policies, this is a finding.

Fix: F-84937r1_fix

This requirement is not applicable for the DoDIN Backbone. Configure ACLs and filters to allow or deny traffic for specific source and destination addresses as well as ports and protocols. Apply the filters inbound or outbound on the appropriate external and internal interfaces. Policy-based routing can also be implemented if needed.

The router must not be configured to have any feature enabled that calls home to the vendor.

SC-7 - Medium - CCI-002403 - V-78211 - SV-92917r1_rule

RMF Control

SC-7

Severity

CCI

Version

SRG-NET-000195-RTR-000083

Vuln IDs

V-78211

Rule IDs

SV-92917r1_rule

Call home services will routinely send data such as configuration and diagnostic information to the vendor for routine or emergency analysis and troubleshooting. There is a risk that transmission of sensitive data sent to unauthorized persons could result in data loss or downtime due to an attack.

Checks: C-77767r1_chk

Verify the call home service is disabled on the device. If a call home service is enabled, this is a finding.

Fix: F-84939r1_fix

Configure the network device to disable the call home service or feature.

The router must not be configured to have any zero-touch deployment feature enabled when connected to an operational network.

SC-5 - Medium - CCI-002385 - V-78213 - SV-92919r1_rule

RMF Control

SC-5

Severity

CCI

Version

SRG-NET-000362-RTR-000109

Vuln IDs

V-78213

Rule IDs

SV-92919r1_rule

Network devices that are configured via a zero-touch deployment or auto-loading feature can have their startup configuration or image pushed to the device for installation via TFTP or Remote Copy (rcp). Loading an image or configuration file from the network is taking a security risk because the file could be intercepted by an attacker who could corrupt the file, resulting in a denial of service.

Checks: C-77769r1_chk

Review the device configuration to determine if a configuration auto-loading or zero-touch deployment feature is enabled. If a configuration auto-loading feature or zero-touch deployment feature is enabled, this is a finding. Note: Auto-configuration or zero-touch deployment features can be enabled when the router is offline for the purpose of image loading or building out the configuration. In addition, this would not be applicable to the provisioning of virtual routers via a software-defined network (SDN) orchestration system.

Fix: F-84941r1_fix

Disable all configuration auto-loading or zero-touch deployment features.

The router must be configured to restrict traffic destined to itself.

SC-7 - High - CCI-001097 - V-78215 - SV-92921r1_rule

RMF Control

SC-7

Severity

CCI

Version

SRG-NET-000205-RTR-000001

Vuln IDs

V-78215

Rule IDs

SV-92921r1_rule

The router must be able to securely handle specific control plane and management plane traffic that is destined to it. Using the ingress filter on forwarding interfaces is a method that has been used in the past to filter both forwarding path and receive path traffic. However, this method does not scale well as the number of interfaces grows and the size of the ingress filters grows. Applying a small and manageable filter directly on the router’s receive path to restrict this traffic is considered an industry best practice.

Checks: C-77771r1_chk

Review the access control list (ACL) or filter for the router receive path and verify that it will only process specific management plane and control plane traffic from specific sources. If the router is not configured with a receive-path filter to restrict traffic destined to itself, this is a finding. Note: If the platform does not support the receive path filter, verify that all Layer 3 interfaces have an ingress ACL to control what packets are allowed to be destined to the router for processing.

Fix: F-84943r1_fix

Configure all routers with receive path filters to restrict traffic destined to the router.

The router must be configured to drop all fragmented Internet Control Message Protocol (ICMP) packets destined to itself.

SC-7 - Medium - CCI-001097 - V-78217 - SV-92923r1_rule

RMF Control

SC-7

Severity

CCI

Version

SRG-NET-000205-RTR-000002

Vuln IDs

V-78217

Rule IDs

SV-92923r1_rule

Fragmented ICMP packets can be generated by hackers for DoS attacks such as Ping O' Death and Teardrop. It is imperative that all fragmented ICMP packets are dropped.

Checks: C-77773r1_chk

Review the access control list (ACL) or filter for the router receive path. Verify that it will drop all fragmented ICMP packets destined to itself. If the router is not configured with a receive-path filter to drop all fragmented ICMP packets, this is a finding. Note: If the platform does not support the receive path filter, verify that all Layer 3 interfaces have an ingress ACL to control what packets are allowed to be destined to the router for processing.

Fix: F-84945r1_fix

Ensure all routers have their receive path filter configured to drop all fragmented ICMP packets.

The router must be configured to have Gratuitous ARP disabled on all external interfaces.

SC-5 - Medium - CCI-002385 - V-78219 - SV-92925r1_rule

RMF Control

SC-5

Severity

CCI

Version

SRG-NET-000362-RTR-000111

Vuln IDs

V-78219

Rule IDs

SV-92925r1_rule

A gratuitous ARP is an ARP broadcast in which the source and destination MAC addresses are the same. It is used to inform the network about a host IP address. A spoofed gratuitous ARP message can cause network mapping information to be stored incorrectly, causing network malfunction.

Checks: C-77775r1_chk

Review the configuration to determine if gratuitous ARP is disabled on all external interfaces. If gratuitous ARP is enabled on any external interface, this is a finding.

Fix: F-84947r1_fix

Disable gratuitous ARP on all external interfaces.

The router must be configured to have IP directed broadcast disabled on all interfaces.

SC-5 - Low - CCI-002385 - V-78221 - SV-92927r1_rule

RMF Control

SC-5

Severity

CCI

Version

SRG-NET-000362-RTR-000112

Vuln IDs

V-78221

Rule IDs

SV-92927r1_rule

An IP directed broadcast is a datagram sent to the broadcast address of a subnet that is not directly attached to the sending machine. The directed broadcast is routed through the network as a unicast packet until it arrives at the target subnet, where it is converted into a link-layer broadcast. Because of the nature of the IP addressing architecture, only the last router in the chain, which is connected directly to the target subnet, can conclusively identify a directed broadcast. IP directed broadcasts are used in the extremely common and popular smurf, or denial-of-service (DoS), attacks. In a smurf attack, the attacker sends Internet Control Message Protocol (ICMP) echo requests from a falsified source address to a directed broadcast address, causing all the hosts on the target subnet to send replies to the falsified source. By sending a continuous stream of such requests, the attacker can create a much larger stream of replies, which can completely inundate the host whose address is being falsified. This service should be disabled on all interfaces when not needed to prevent smurf and DoS attacks. Directed broadcast can be enabled on internal facing interfaces to support services such as Wake-On-LAN. Case scenario may also include support for legacy applications where the content server and the clients do not support multicast. The content servers send streaming data using UDP broadcast. Used in conjunction with the IP multicast helper-map feature, broadcast data can be sent across a multicast topology. The broadcast streams are converted to multicast and vice versa at the first-hop routers and last-hop routers before entering and leaving the multicast transit area respectively. The last-hop router must convert the multicast to broadcast. Hence, this interface must be configured to forward a broadcast packet (i.e., a directed broadcast address is converted to the all nodes broadcast address).

Checks: C-77777r1_chk

Review the router configuration to determine if IP directed broadcast is enabled. If IP directed broadcast is enabled on Layer 3 interfaces, this is a finding.

Fix: F-84949r1_fix

Disable IP directed broadcasts on all Layer 3 interfaces.

The router must be configured to have Internet Control Message Protocol (ICMP) unreachable notifications disabled on all external interfaces.

SC-5 - Medium - CCI-002385 - V-78223 - SV-92929r1_rule

RMF Control

SC-5

Severity

CCI

Version

SRG-NET-000362-RTR-000113

Vuln IDs

V-78223

Rule IDs

SV-92929r1_rule

The ICMP supports IP traffic by relaying information about paths, routes, and network conditions. Routers automatically send ICMP messages under a wide variety of conditions. Host unreachable ICMP messages are commonly used by attackers for network mapping and diagnosis.

Checks: C-77779r1_chk

Review the device configuration to determine if controls have been defined to ensure the router does not send ICMP unreachable notifications out to any external interfaces. If ICMP unreachable notifications are enabled on any external interfaces, this is a finding.

Fix: F-84951r1_fix

Disable ICMP unreachable notifications on all external interfaces.

The router must be configured to have Internet Control Message Protocol (ICMP) mask replies disabled on all external interfaces.

SC-5 - Medium - CCI-002385 - V-78225 - SV-92931r1_rule

RMF Control

SC-5

Severity

CCI

Version

SRG-NET-000362-RTR-000114

Vuln IDs

V-78225

Rule IDs

SV-92931r1_rule

The ICMP supports IP traffic by relaying information about paths, routes, and network conditions. Routers automatically send ICMP messages under a wide variety of conditions. Mask Reply ICMP messages are commonly used by attackers for network mapping and diagnosis.

Checks: C-77781r1_chk

Review the device configuration to determine if controls have been defined to ensure the router does not send ICMP Mask Reply messages out to any external interfaces. If ICMP Mask Reply messages are enabled on any external interfaces, this is a finding.

Fix: F-84953r1_fix

Disable ICMP mask replies on all external interfaces.

The router must be configured to have Internet Control Message Protocol (ICMP) redirects disabled on all external interfaces.

SC-5 - Medium - CCI-002385 - V-78227 - SV-92933r1_rule

RMF Control

SC-5

Severity

CCI

Version

SRG-NET-000362-RTR-000115

Vuln IDs

V-78227

Rule IDs

SV-92933r1_rule

The ICMP supports IP traffic by relaying information about paths, routes, and network conditions. Routers automatically send ICMP messages under a wide variety of conditions. Redirect ICMP messages are commonly used by attackers for network mapping and diagnosis.

Checks: C-77783r1_chk

Review the device configuration to determine if controls have been defined to ensure the router does not send ICMP Redirect messages out to any external interfaces. If ICMP Redirect messages are enabled on any external interfaces, this is a finding.

Fix: F-84955r1_fix

Disable ICMP redirects on all external interfaces.

The router must be configured to log all packets that have been dropped.

AU-3 - Low - CCI-000134 - V-78229 - SV-92935r1_rule

RMF Control

AU-3

Severity

CCI

CCI-000134

Version

SRG-NET-000078-RTR-000001

Vuln IDs

V-78229

Rule IDs

SV-92935r1_rule

Auditing and logging are key components of any security architecture. It is essential for security personnel to know what is being done or attempted to be done, and by whom, to compile an accurate risk assessment. Auditing the actions on network devices provides a means to recreate an attack or identify a configuration mistake on the device.

Checks: C-77785r1_chk

Review the router interface access control lists (ACLs) to verify all deny statements are logged. If packets being dropped are not logged, this is a finding.

Fix: F-84957r1_fix

Configure interface ACLs to log all deny statements.

The router must be configured to produce audit records containing information to establish where the events occurred.

AU-3 - Medium - CCI-000132 - V-78231 - SV-92937r1_rule

RMF Control

AU-3

Severity

CCI

CCI-000132

Version

SRG-NET-000076-RTR-000001

Vuln IDs

V-78231

Rule IDs

SV-92937r1_rule

Without establishing where events occurred, it is impossible to establish, correlate, and investigate the events leading up to an outage or attack. In order to compile an accurate risk assessment and provide forensic analysis, it is essential for security personnel to know where events occurred, such as router components, modules, device identifiers, node names, and functionality. Associating information about where the event occurred within the network provides a means of investigating an attack, recognizing resource utilization or capacity thresholds, or identifying an improperly configured router.

Checks: C-77787r1_chk

The router must log all packets that have been dropped via the access control list (ACL). If the router fails to log all packets that have been dropped via the ACL, this is a finding. Log output must contain an interface name as to where the packet was filtered. If the logged output does not contain an interface name as to where the packet was filtered, this is a finding.

Fix: F-84959r1_fix

Configure the router to record the interface in the log record for packets being dropped.

The router must be configured to produce audit records containing information to establish the source of the events.

AU-3 - Medium - CCI-000133 - V-78233 - SV-92939r1_rule

RMF Control

AU-3

Severity

CCI

CCI-000133

Version

SRG-NET-000077-RTR-000001

Vuln IDs

V-78233

Rule IDs

SV-92939r1_rule

Without establishing the source of the event, it is impossible to establish, correlate, and investigate the events leading up to an outage or attack. In order to compile an accurate risk assessment and provide forensic analysis, security personnel need to know the source of the event. In addition to logging where events occur within the network, the audit records must also identify sources of events such as IP addresses, processes, and node or device names.

Checks: C-77789r1_chk

The router must log all packets that have been dropped via the access control list. If the router fails to log all packets that have been dropped via the control list, this is a finding. Log output must contain the source IP address and port of the filtered packets. If the logged output does not contain source IP address and port of the filtered packets, this is a finding.

Fix: F-84961r1_fix

Configure the router to record the source address in the log record for packets being dropped.

The router must be configured to disable the auxiliary port unless it is connected to a secured modem providing encryption and authentication.

AC-4 - Low - CCI-001414 - V-78235 - SV-92941r1_rule

RMF Control

AC-4

Severity

CCI

Version

SRG-NET-000019-RTR-000001

Vuln IDs

V-78235

Rule IDs

SV-92941r1_rule

The use of POTS lines to modems connecting to network devices provides clear text of authentication traffic over commercial circuits that could be captured and used to compromise the network. Additional war dial attacks on the device could degrade the device and the production network. Secured modem devices must be able to authenticate users and must negotiate a key exchange before full encryption takes place. The modem will provide full encryption capability (Triple DES) or stronger. The technician who manages these devices will be authenticated using a key fob and granted access to the appropriate maintenance port; thus, the technician will gain access to the managed device (router, switch, etc.). The token provides a method of strong (two-factor) user authentication. The token works in conjunction with a server to generate one-time user passwords that will change values at second intervals. The user must know a personal identification number (PIN) and possess the token to be allowed access to the device.

Checks: C-77791r1_chk

Review the configuration and verify that the auxiliary port is disabled unless a secured modem providing encryption and authentication is connected to it. If the auxiliary port is not disabled or is not connected to a secured modem when it is enabled, this is a finding.

Fix: F-84963r1_fix

Disable the auxiliary port. If used for out-of-band administrative access, the port must be connected to a secured modem providing encryption and authentication.

The perimeter router must be configured to deny network traffic by default and allow network traffic by exception.

SC-7 - High - CCI-001109 - V-78237 - SV-92943r1_rule

RMF Control

SC-7

Severity

CCI

CCI-001109

Version

SRG-NET-000202-RTR-000001

Vuln IDs

V-78237

Rule IDs

SV-92943r1_rule

A deny-all, permit-by-exception network communications traffic policy ensures that only connections that are essential and approved are allowed. This requirement applies to both inbound and outbound network communications traffic. All inbound and outbound traffic must be denied by default. Firewalls and perimeter routers should only allow traffic through that is explicitly permitted. The initial defense for the internal network is to block any traffic at the perimeter that is attempting to make a connection to a host residing on the internal network. In addition, allowing unknown or undesirable outbound traffic by the firewall or router will establish a state that will permit the return of this undesirable traffic inbound.

Checks: C-77793r1_chk

This requirement is not applicable for the DoDIN Backbone. Review the router configuration to verify that the access control list (ACL) or filter is configured to allow specific ports and protocols and deny all other traffic. The filter must be configured inbound on all external interfaces. If the ACL or filter is not configured to allow specific ports and protocols and deny all other traffic, this is a finding. If the filter is not configured inbound on all external interfaces, this is a finding.

Fix: F-84965r1_fix

This requirement is not applicable for the DoDIN Backbone. Configure the perimeter router to deny network traffic by default and allow network traffic by exception.

The perimeter router must be configured to block inbound packets with source Bogon IP address prefixes.

SC-7 - Medium - CCI-002403 - V-78239 - SV-92945r1_rule

RMF Control

SC-7

Severity

CCI

Version

SRG-NET-000364-RTR-000110

Vuln IDs

V-78239

Rule IDs

SV-92945r1_rule

Packets with Bogon IP source addresses should never be allowed to traverse the IP core. Bogon IP networks are RFC1918 addresses or address blocks that have never been assigned by the IANA or have been reserved.

Checks: C-77795r1_chk

This requirement is not applicable for the DoDIN Backbone. Review the router configuration to verify that an ingress access control list (ACL) is applied to all external interfaces. Verify that the ingress ACL is blocking packets with Bogon source addresses. If the router is not configured to block inbound packets with source Bogon IP address prefixes, this is a finding.

Fix: F-84967r1_fix

This requirement is not applicable for the DoDIN Backbone. Configure the perimeter to block inbound packets with Bogon source addresses.

The perimeter router must be configured to protect an enclave connected to an alternate gateway by using an inbound filter that only permits packets with destination addresses within the sites address space.

AC-4 - High - CCI-001414 - V-78241 - SV-92947r1_rule

RMF Control

AC-4

Severity

CCI

Version

SRG-NET-000019-RTR-000008

Vuln IDs

V-78241

Rule IDs

SV-92947r1_rule

Enclaves with alternate gateway connections must take additional steps to ensure there is no compromise on the enclave network or NIPRNet. Without verifying the destination address of traffic coming from the site's alternate gateway, the perimeter router could be routing transit data from the Internet into the NIPRNet. This could also make the perimeter router vulnerable to a denial-of-service (DoS) attack as well as provide a back door into the NIPRNet. The DoD enclave must ensure the ingress filter applied to external interfaces on a perimeter router connecting to an Approved Gateway is secure through filters permitting packets with a destination address belonging to the DoD enclave's address block.

Checks: C-77797r1_chk

This requirement is not applicable for the DoDIN Backbone. Review the configuration of each router interface connecting to an alternate gateway. Verify each permit statement of the ingress filter only permits packets with destination addresses of the site's NIPRNet address space or a destination address belonging to the address block assigned by the alternate gateway network service provider. If the ingress filter permits packets with addresses other than those specified, such as destination addresses of the site's NIPRNet address space or a destination address belonging to the address block assigned by the alternate gateway network service provider, this is a finding.

Fix: F-84969r1_fix

This requirement is not applicable for the DoDIN Backbone. Configure the ingress filter of the perimeter router connected to an alternate gateway to only permit packets with destination addresses of the site's NIPRNet address space or a destination address belonging to the address block assigned by the alternate gateway network service provider.

The perimeter router must be configured to filter traffic destined to the enclave in accordance with the guidelines contained in DoD Instruction 8551.1.

SC-7 - Medium - CCI-001097 - V-78243 - SV-92949r1_rule

RMF Control

SC-7

Severity

CCI

Version

SRG-NET-000205-RTR-000003

Vuln IDs

V-78243

Rule IDs

SV-92949r1_rule

Vulnerability assessments must be reviewed by the System Administrator, and protocols must be approved by the Information Assurance (IA) staff before entering the enclave. Access control lists (ACLs) are the first line of defense in a layered security approach. They permit authorized packets and deny unauthorized packets based on port or service type. They enhance the posture of the network by not allowing packets to reach a potential target within the security domain. The lists provided are highly susceptible ports and services that should be blocked or limited as much as possible without adversely affecting customer requirements. Auditing packets attempting to penetrate the network but that are stopped by an ACL will allow network administrators to broaden their protective ring and more tightly define the scope of operation. If the perimeter is in a Deny-by-Default posture and what is allowed through the filter is in accordance with DoD Instruction 8551.1, and if the permit rule is explicitly defined with explicit ports and protocols allowed, then all requirements related to PPS being blocked would be satisfied.

Checks: C-77799r1_chk

This requirement is not applicable for the DoDIN Backbone. Review the router configuration to verify that the ingress and egress filters are in accordance with DoD 8551. If the router does not filter traffic in accordance with the guidelines contained in DoD 8551, this is a finding.

Fix: F-84971r1_fix

This requirement is not applicable for the DoDIN Backbone. Configure the router to use ingress and egress ACLs to restrict traffic in accordance with the guidelines contained in DOD Instruction 8551.1 for all services and protocols required for operational commitments.

The perimeter router must be configured to filter ingress traffic at the external interface on an inbound direction.

SC-7 - Medium - CCI-001097 - V-78245 - SV-92951r1_rule

RMF Control

SC-7

Severity

CCI

Version

SRG-NET-000205-RTR-000004

Vuln IDs

V-78245

Rule IDs

SV-92951r1_rule

Access lists are used to separate data traffic into that which it will route (permitted packets) and that which it will not route (denied packets). Secure configuration of routers makes use of access lists for restricting access to services on the router itself as well as for filtering traffic passing through the router. Inbound versus Outbound: It should be noted that some operating systems default access lists are applied to the outbound queue. The more secure solution is to apply the access list to the inbound queue for three reasons: - The router can protect itself before damage is inflicted. - The input port is still known and can be filtered upon. - It is more efficient to filter packets before routing them.

Checks: C-77801r1_chk

This requirement is not applicable for the DoDIN Backbone. Review the router configuration to verify that the ingress ACL is bound to the external interface in an inbound direction. If the router is not configured to filter traffic entering the network at the external interface in an inbound direction, this is a finding.

Fix: F-84973r1_fix

This requirement is not applicable for the DoDIN Backbone. Bind the ingress ACL to the external interface (inbound).

The perimeter router must be configured to filter egress traffic at the internal interface on an inbound direction.

SC-7 - Medium - CCI-001097 - V-78247 - SV-92953r1_rule

RMF Control

SC-7

Severity

CCI

Version

SRG-NET-000205-RTR-000005

Vuln IDs

V-78247

Rule IDs

SV-92953r1_rule

Checks: C-77803r1_chk

This requirement is not applicable for the DoDIN Backbone. Review the router configuration to verify that the egress ACL is bound to the internal interface in an inbound direction. If the router is not configured to filter traffic leaving the network at the external interface in an inbound direction, this is a finding.

Fix: F-84975r1_fix

This requirement is not applicable for the DoDIN Backbone. Configure an egress ACL bound to the internal interface in an inbound direction to filter traffic leaving the network.

The perimeter router must be configured to have Link Layer Discovery Protocols (LLDPs) disabled on all external interfaces.

SC-7 - Low - CCI-002403 - V-78249 - SV-92955r1_rule

RMF Control

SC-7

Severity

CCI

Version

SRG-NET-000364-RTR-000111

Vuln IDs

V-78249

Rule IDs

SV-92955r1_rule

LLDPs are primarily used to obtain protocol addresses of neighboring devices and discover platform capabilities of those devices. Use of SNMP with the LLDP Management Information Base (MIB) allows network management applications to learn the device type and the SNMP agent address of neighboring devices, thereby enabling the application to send SNMP queries to those devices. LLDPs are also media- and protocol-independent as they run over the data link layer; therefore, two systems that support different network-layer protocols can still learn about each other. Allowing LLDP messages to reach external network nodes is dangerous as it provides an attacker a method to obtain information of the network infrastructure that can be useful to plan an attack.

Checks: C-77805r1_chk

This requirement is not applicable for the DoDIN Backbone. Review all router configurations to ensure LLDPs are not included in the global configuration or LLDPs are not included for each active external interface. Examples of LLDPs are Cisco Discovery Protocol (CDP), Link Layer Discovery Protocol (LLDP), and Link Layer Discovery Protocol - Media Endpoint Discovery (LLDP-MED). If LLDPs are configured globally or on any external interface, this is a finding.

Fix: F-84977r1_fix

This requirement is not applicable for the DoDIN Backbone. Disable LLDPs on all external interfaces.

The perimeter router must be configured to have Proxy ARP disabled on all external interfaces.

SC-7 - Medium - CCI-002403 - V-78251 - SV-92957r1_rule

RMF Control

SC-7

Severity

CCI

Version

SRG-NET-000364-RTR-000112

Vuln IDs

V-78251

Rule IDs

SV-92957r1_rule

When Proxy ARP is enabled on a Cisco router, it allows that router to extend the network (at Layer 2) across multiple interfaces (LAN segments). Because proxy ARP allows hosts from different LAN segments to look like they are on the same segment, proxy ARP is only safe when used between trusted LAN segments. Attackers can leverage the trusting nature of proxy ARP by spoofing a trusted host and then intercepting packets. Proxy ARP should always be disabled on router interfaces that do not require it, unless the router is being used as a LAN bridge.

Checks: C-77807r1_chk

This requirement is not applicable for the DoDIN Backbone. Review the router configuration to determine if IP Proxy ARP is disabled on all external interfaces. If IP Proxy ARP is enabled on any external interface, this is a finding.

Fix: F-84979r1_fix

This requirement is not applicable for the DoDIN Backbone. Disable IP Proxy ARP on all external interfaces.

The perimeter router must be configured to block all outbound management traffic.

SC-7 - Medium - CCI-001097 - V-78253 - SV-92959r1_rule

RMF Control

SC-7

Severity

CCI

Version

SRG-NET-000364-RTR-000113

Vuln IDs

V-78253

Rule IDs

SV-92959r1_rule

For in-band management, the management network must have its own subnet in order to enforce control and access boundaries provided by Layer 3 network nodes, such as routers and firewalls. Management traffic between the managed network elements and the management network is routed via the same links and nodes as that used for production or operational traffic. Safeguards must be implemented to ensure that the management traffic does not leak past the perimeter of the managed network.

Checks: C-77809r1_chk

This requirement is not applicable for the DoDIN Backbone. The perimeter router of the managed network must be configured with an access control list (ACL) or filter on the egress interface to block all management traffic. If management traffic is not blocked at the perimeter, this is a finding.

Fix: F-84981r1_fix

This requirement is not applicable for the DoDIN Backbone. Configure the perimeter router of the managed network with an ACL or filter on the egress interface to block all outbound management traffic.

The out-of-band management (OOBM) gateway must be configured to transport management traffic to the Network Operations Center (NOC) via dedicated circuit, MPLS/VPN service, or IPsec tunnel.

SC-7 - Medium - CCI-001097 - V-78255 - SV-92961r1_rule

RMF Control

SC-7

Severity

CCI

Version

SRG-NET-000205-RTR-000009

Vuln IDs

V-78255

Rule IDs

SV-92961r1_rule

Using dedicated paths, the OOBM backbone connects the OOBM gateway routers located at the edge of the managed network and at the NOC. Dedicated links can be deployed using provisioned circuits or MPLS Layer 2 and Layer 3 VPN services or implementing a secured path with gateway-to-gateway IPsec tunnels. The tunnel mode ensures that the management traffic will be logically separated from any other traffic traversing the same path.

Checks: C-77811r1_chk

This requirement is not applicable for the DoDIN Backbone. Review the network topology diagram to determine connectivity between the managed network and the NOC. Review the OOBM gateway router configuration to validate the path and interface that the management traffic traverses. If management traffic is not transported between the managed network and the NOC via dedicated circuit, MPLS/VPN service, or IPsec tunnel, this is a finding.

Fix: F-84983r1_fix

This requirement is not applicable for the DoDIN Backbone. Ensure that a dedicated circuit, MPLS/VPN service, or IPsec tunnel is deployed to transport management traffic between the managed network and the NOC.

The out-of-band management (OOBM) gateway router must be configured to forward only authorized management traffic to the Network Operations Center (NOC).

SC-7 - Medium - CCI-001097 - V-78257 - SV-92963r1_rule

RMF Control

SC-7

Severity

CCI

Version

SRG-NET-000205-RTR-000010

Vuln IDs

V-78257

Rule IDs

SV-92963r1_rule

The OOBM network is an IP network used exclusively for the transport of OAM&P data from the network being managed to the OSS components located at the NOC. Its design provides connectivity to each managed network device, enabling network management traffic to flow between the managed network elements and the NOC. This allows the use of paths separate from those used by the managed network.

Checks: C-77813r1_chk

This requirement is not applicable for the DoDIN Backbone. Review the network topology diagram to determine connectivity between the managed network and the NOC. Review the OOBM gateway router configuration to validate the path that the management traffic traverses. Verify that only management traffic is forwarded through the OOBM interface or IPsec tunnel. If traffic other than authorized management traffic is permitted through the OOBM interface or IPsec tunnel, this is a finding.

Fix: F-84985r1_fix

This requirement is not applicable for the DoDIN Backbone. Configure filters based on port, source IP address, and destination IP address to permit only authorized management traffic into IPsec tunnels or the OOBM interface used for forwarding management data.

The router providing connectivity to the NOC must be configured to forward all in-band management traffic via an IPsec tunnel.

SC-7 - Medium - CCI-001097 - V-78263 - SV-92969r1_rule

RMF Control

SC-7

Severity

CCI

Version

SRG-NET-000205-RTR-000013

Vuln IDs

V-78263

Rule IDs

SV-92969r1_rule

When the production network is managed in-band, the management network could be housed at a NOC that is located remotely at single or multiple interconnected sites. NOC interconnectivity, as well as connectivity between the NOC and the managed network, must be enabled using IPsec tunnels to provide the separation and integrity of the managed traffic.

Checks: C-77819r1_chk

This requirement is not applicable for the DoDIN Backbone. Verify that all traffic from the managed network to the management network and vice-versa is secured via IPsec tunnel. If the management traffic is not secured via IPsec tunnel, this is a finding.

Fix: F-84991r1_fix

This requirement is not applicable for the DoDIN Backbone. Ensure that all traffic from the managed network to the management network and vice-versa is secured via IPsec tunnel.

The BGP router must be configured to use a unique key for each autonomous system (AS) that it peers with.

CM-6 - Medium - CCI-000366 - V-78265 - SV-92971r1_rule

RMF Control

CM-6

Severity

CCI

Version

SRG-NET-000025-RTR-000021

Vuln IDs

V-78265

Rule IDs

SV-92971r1_rule

If the same keys are used between eBGP neighbors, the chance of a hacker compromising any of the BGP sessions increases. It is possible that a malicious user exists in one autonomous system who would know the key used for the eBGP session. This user would then be able to hijack BGP sessions with other trusted neighbors.

Checks: C-77821r1_chk

Interview the ISSM and router administrator to determine if unique keys are being used. If unique keys are not being used, this is a finding.

Fix: F-84993r1_fix

Configure all eBGP routers with unique keys for each eBGP neighbor that it peers with.

The BGP router must be configured to reject inbound route advertisements for any Bogon prefixes.

AC-4 - Medium - CCI-001368 - V-78267 - SV-92973r1_rule

RMF Control

AC-4

Severity

CCI

Version

SRG-NET-000018-RTR-000002

Vuln IDs

V-78267

Rule IDs

SV-92973r1_rule

Accepting route advertisements for Bogon prefixes can result in the local autonomous system (AS) becoming a transit for malicious traffic as it will in turn advertise these prefixes to neighbor autonomous systems.

Checks: C-77823r1_chk

Review the router configuration to verify that it will reject routes of any Bogon prefixes. The prefix filter must be referenced inbound on the appropriate BGP neighbor statements. If the router is not configured to reject inbound route advertisements for any Bogon prefixes, this is a finding.

Fix: F-84995r1_fix

Ensure all eBGP routers are configured to reject inbound route advertisements for any Bogon prefixes.

The BGP router must be configured to reject inbound route advertisements for any prefixes belonging to the local autonomous system (AS).

AC-4 - Medium - CCI-001368 - V-78269 - SV-92975r1_rule

RMF Control

AC-4

Severity

CCI

Version

SRG-NET-000018-RTR-000003

Vuln IDs

V-78269

Rule IDs

SV-92975r1_rule

Accepting route advertisements belonging to the local AS can result in traffic looping or being black holed, or at a minimum using a non-optimized path.

Checks: C-77825r1_chk

Review the router configuration to verify that it will reject routes belonging to the local AS. The prefix filter must be referenced inbound on the appropriate BGP neighbor statements. If the router is not configured to reject inbound route advertisements belonging to the local AS, this is a finding.

Fix: F-84997r1_fix

Ensure all eBGP routers are configured to reject inbound route advertisements for any prefixes belonging to the local AS.

The BGP router must be configured to reject inbound route advertisements from a customer edge (CE) router for prefixes that are not allocated to that customer.

AC-4 - Medium - CCI-001368 - V-78271 - SV-92977r1_rule

RMF Control

AC-4

Severity

CCI

Version

SRG-NET-000018-RTR-000004

Vuln IDs

V-78271

Rule IDs

SV-92977r1_rule

As a best practice, a service provider should only accept customer prefixes that have been assigned to that customer and any peering autonomous systems. A multi-homed customer with BGP speaking routers connected to the Internet or other external networks could be breached and used to launch a prefix de-aggregation attack. Without ingress route filtering of customers, the effectiveness of such an attack could impact the entire IP core and its customers.

Checks: C-77827r1_chk

Review the router configuration to verify that there are filters defined to only accept routes for prefixes that belong to specific customers. The prefix filter must be referenced inbound on the appropriate BGP neighbor statement. If the router is not configured to reject inbound route advertisements from each CE router for prefixes that are not allocated to that customer, this is a finding. Note: Routes to PE-CE links within a VPN are needed for troubleshooting end-to-end connectivity across the MPLS/IP backbone. Hence, these prefixes are an exception to this requirement.

Fix: F-84999r1_fix

Configure all eBGP routers to reject inbound route advertisements from a CE router for prefixes that are not allocated to that customer.

The BGP router must be configured to reject outbound route advertisements for any prefixes that do not belong to any customers or the local autonomous system (AS).

AC-4 - Medium - CCI-001368 - V-78273 - SV-92979r1_rule

RMF Control

AC-4

Severity

CCI

Version

SRG-NET-000018-RTR-000005

Vuln IDs

V-78273

Rule IDs

SV-92979r1_rule

Advertisement of routes by an autonomous system for networks that do not belong to any of its customers pulls traffic away from the authorized network. This causes a denial of service (DoS) on the network that allocated the block of addresses and may cause a DoS on the network that is inadvertently advertising it as the originator. It is also possible that a misconfigured or compromised router within the GIG IP core could redistribute IGP routes into BGP, thereby leaking internal routes.

Checks: C-77829r1_chk

Review the router configuration to verify that there is a filter defined to only advertise routes for prefixes that belong to any customers or the local AS. The prefix filter must be referenced outbound on the appropriate BGP neighbor statements. If the router is not configured to reject outbound route advertisements that belong to any customers or the local AS, this is a finding.

Fix: F-85001r1_fix

Configure all eBGP routers to filter outbound route advertisements for prefixes that are not allocated to or belong to any customer or the local AS.

The BGP router must be configured to reject outbound route advertisements for any prefixes belonging to the IP core.

SC-7 - Medium - CCI-001097 - V-78275 - SV-92981r1_rule

RMF Control

SC-7

Severity

CCI

Version

SRG-NET-000205-RTR-000006

Vuln IDs

V-78275

Rule IDs

SV-92981r1_rule

Outbound route advertisements belonging to the core can result in traffic either looping or being black holed, or at a minimum, using a non-optimized path.

Checks: C-77833r1_chk

Review the router configuration to verify that there is a filter defined to block route advertisements for prefixes that belong to the IP core. The prefix filter must be referenced outbound on the appropriate BGP neighbor statements. If the router is not configured to reject outbound route advertisements that belong to the IP core, this is a finding.

Fix: F-85003r1_fix

Configure all eBGP routers to filter outbound route advertisements belonging to the IP core.

The BGP router must be configured to reject route advertisements from BGP peers that do not list their autonomous system (AS) number as the first AS in the AS_PATH attribute.

AC-4 - Low - CCI-000032 - V-78277 - SV-92983r1_rule

RMF Control

AC-4

Severity

CCI

CCI-000032

Version

SRG-NET-000018-RTR-000006

Vuln IDs

V-78277

Rule IDs

SV-92983r1_rule

Verifying the path a route has traversed will ensure the IP core is not used as a transit network for unauthorized or possibly even Internet traffic. All autonomous system boundary routers (ASBRs) must ensure updates received from eBGP peers list their AS number as the first AS in the AS_PATH attribute.

Checks: C-77835r1_chk

Review the router configuration to verify the router is configured to deny updates received from eBGP peers that do not list their AS number as the first AS in the AS_PATH attribute. If the router is not configured to reject updates from peers that do not list their AS number as the first AS in the AS_PATH attribute, this is a finding.

Fix: F-85005r1_fix

Configure all ASBRs to deny updates received from eBGP peers that do not list their AS number as the first AS in the AS_PATH attribute.

The BGP router must be configured to use the maximum prefixes feature to protect against route table flooding and prefix de-aggregation attacks.

SC-5 - Medium - CCI-002385 - V-78279 - SV-92985r1_rule

RMF Control

SC-5

Severity

CCI

Version

SRG-NET-000362-RTR-000117

Vuln IDs

V-78279

Rule IDs

SV-92985r1_rule

The effects of prefix de-aggregation can degrade router performance due to the size of routing tables and also result in black-holing legitimate traffic. Initiated by an attacker or a misconfigured router, prefix de-aggregation occurs when the announcement of a large prefix is fragmented into a collection of smaller prefix announcements. In 1997, misconfigured routers in the Florida Internet Exchange network (AS7007) de-aggregated every prefix in their routing table and started advertising the first /24 block of each of these prefixes as their own. Faced with this additional burden, the internal routers became overloaded and crashed repeatedly. This caused prefixes advertised by these routers to disappear from routing tables and reappear when the routers came back online. As the routers came back after crashing, they were flooded with the routing table information by their neighbors. The flood of information would again overwhelm the routers and cause them to crash. This process of route flapping served to destabilize not only the surrounding network but also the entire Internet. Routers trying to reach those addresses would choose the smaller, more specific /24 blocks first. This caused backbone networks throughout North America and Europe to crash. Maximum prefix limits on peer connections combined with aggressive prefix-size filtering of customers' reachability advertisements will effectively mitigate the de-aggregation risk. BGP maximum prefix must be used on all eBGP routers to limit the number of prefixes that it should receive from a particular neighbor, whether customer or peering AS. Consider each neighbor and how many routes they should be advertising and set a threshold slightly higher than the number expected.

Checks: C-77837r1_chk

Review the router configuration to verify that the number of received prefixes from each eBGP neighbor is controlled. If the router is not configured to control the number of prefixes received from each peer to protect against route table flooding and prefix de-aggregation attacks, this is a finding.

Fix: F-85007r1_fix

Configure all eBGP routers to use the maximum prefixes feature to protect against route table flooding and prefix de-aggregation attacks.

The BGP router must be configured to limit the prefix size on any inbound route advertisement to /24 or the least significant prefixes issued to the customer.

SC-5 - Low - CCI-002385 - V-78281 - SV-92987r1_rule

RMF Control

SC-5

Severity

CCI

Version

SRG-NET-000362-RTR-000118

Vuln IDs

V-78281

Rule IDs

SV-92987r1_rule

Checks: C-77839r1_chk

Review the router configuration to verify that there is a filter to reject inbound route advertisements that are greater than /24 or the least significant prefixes issued to the customer, whichever is larger. If the router is not configured to limit the prefix size on any inbound route advertisement to /24 or the least significant prefixes issued to the customer, this is a finding.

Fix: F-85009r1_fix

Ensure all eBGP routers are configured to limit the prefix size on any route advertisement to /24 or the least significant prefixes issued to the customer.

The BGP router must be configured to use its loopback address as the source address for iBGP peering sessions.

CM-6 - Low - CCI-000366 - V-78283 - SV-92989r1_rule

RMF Control

CM-6

Severity

CCI

Version

SRG-NET-000512-RTR-000001

Vuln IDs

V-78283

Rule IDs

SV-92989r1_rule

Using a loopback address as the source address offers a multitude of uses for security, access, management, and scalability of the BGP routers. It is easier to construct appropriate ingress filters for router management plane traffic destined to the network management subnet since the source addresses will be from the range used for loopback interfaces instead of a larger range of addresses used for physical interfaces. Log information recorded by authentication and syslog servers will record the router’s loopback address instead of the numerous physical interface addresses. When the loopback address is used as the source for eBGP peering, the BGP session will be harder to hijack since the source address to be used is not known globally—making it more difficult for a hacker to spoof an eBGP neighbor. By using traceroute, a hacker can easily determine the addresses for an eBGP speaker when the IP address of an external interface is used as the source address. The routers within the iBGP domain should also use loopback addresses as the source address when establishing BGP sessions.

Checks: C-77841r1_chk

Review the router configuration to verify that a loopback address has been configured. Verify that a loopback interface is used as the source address for all iBGP sessions. If the router does not use its loopback address as the source address for all iBGP sessions, this is a finding.

Fix: F-85011r1_fix

Ensure that the router’s loopback address is used as the source address when originating traffic.

The MPLS router must be configured to use its loopback address as the source address for LDP peering sessions.

CM-6 - Low - CCI-000366 - V-78285 - SV-92991r1_rule

RMF Control

CM-6

Severity

CCI

Version

SRG-NET-000512-RTR-000002

Vuln IDs

V-78285

Rule IDs

SV-92991r1_rule

Using a loopback address as the source address offers a multitude of uses for security, access, management, and scalability of backbone routers. It is easier to construct appropriate ingress filters for router management plane traffic destined to the network management subnet since the source addresses will be from the range used for loopback interfaces instead of from a larger range of addresses used for physical interfaces. Log information recorded by authentication and syslog servers will record the router's loopback address instead of the numerous physical interface addresses.

Checks: C-77843r1_chk

Review the router configuration to determine if it uses its loopback address as the source address for LDP peering sessions. Verify that a loopback address has been configured as shown in the following example: An MPLS router will use the LDP router ID as the source address for LDP hellos and when establishing TCP sessions with LDP peers; hence, it is necessary to verify that the LDP router ID is the same as the loopback address. By default, routers will assign the LDP router ID using the highest IP address on the router, with preference given to loopback addresses. If the router-id command is specified that overrides this default behavior, verify that it is the IP address of the designated loopback interface. If the router is not configured do use its loopback address for LDP peering, this is a finding.

Fix: F-85013r1_fix

Configure MPLS routers to use their loopback address as the source address for LDP peering sessions.

The MPLS router must be configured to synchronize IGP and LDP to minimize packet loss when an IGP adjacency is established prior to LDP peers completing label exchange.

CM-6 - Low - CCI-000366 - V-78287 - SV-92993r1_rule

RMF Control

CM-6

Severity

CCI

Version

SRG-NET-000512-RTR-000003

Vuln IDs

V-78287

Rule IDs

SV-92993r1_rule

Packet loss can occur when an IGP adjacency is established and the router begins forwarding packets using the new adjacency before the LDP label exchange completes between the peers on that link. Packet loss can also occur if an LDP session closes and the router continues to forward traffic using the link associated with the LDP peer rather than an alternate pathway with a fully synchronized LDP session. The MPLS LDP-IGP Synchronization feature provides a means to synchronize LDP with OSPF or IS-IS to minimize MPLS packet loss. When an IGP adjacency is established on a link but LDP-IGP synchronization is not yet achieved or is lost, the IGP will advertise the max-metric on that link.

Checks: C-77845r1_chk

Review the router OSPF or IS-IS configuration. Verify that LDP will synchronize with the link-state routing protocol. If the router is not configured to synchronize IGP and LDP, this is a finding.

Fix: F-85015r1_fix

Configure the MPLS router to synchronize IGP and LDP, minimizing packet loss when an IGP adjacency is established prior to LDP peers completing label exchange.

The MPLS router with RSVP-TE enabled must be configured with message pacing to adjust maximum burst and maximum number of RSVP messages to an output queue based on the link speed and input queue size of adjacent core routers.

SC-5 - Low - CCI-001095 - V-78289 - SV-92995r1_rule

RMF Control

SC-5

Severity

CCI

Version

SRG-NET-000193-RTR-000001

Vuln IDs

V-78289

Rule IDs

SV-92995r1_rule

RSVP-TE can be used to perform constraint-based routing when building LSP tunnels within the network core that will support QoS and traffic engineering requirements. RSVP-TE is also used to enable MPLS Fast Reroute, a network restoration mechanism that will reroute traffic onto a backup LSP in case of a node or link failure along the primary path. When there is a disruption in the MPLS core, such as a link flap or router reboot, the result is a significant amount of RSVP signaling, such as "PathErr" and "ResvErr" messages that need to be sent for every LSP using that link. When RSVP messages are sent out, they are sent either hop by hop or with the router alert bit set in the IP header. This means that every router along the path must examine the packet to determine if additional processing is required for these RSVP messages. If there is enough signaling traffic in the network, it is possible for an interface to receive more packets for its input queue than it can hold, resulting in dropped RSVP messages and hence slower RSVP convergence. Increasing the size of the interface input queue can help prevent dropping packets; however, there is still the risk of having a burst of signaling traffic that can fill the queue. The best solution is RSVP message pacing to control the rate at which RSVP messages are sent so the input queue on the other end of the link is not overloaded.

Checks: C-77847r1_chk

Review the router configuration to verify that the router has been configured to prevent a burst of RSVP traffic engineering signaling messages from overflowing the input queue of any neighbor core router. If the router with RSVP-TE enabled does not have message pacing configured based on the link speed and input queue size of adjacent core routers, this is a finding.

Fix: F-85017r1_fix

Ensure all routers with RSVP-TE enabled have message pacing configured that will adjust maximum burst and maximum number of RSVP messages to an output queue based on the link speed and input queue size of adjacent core routers.

The MPLS edge routers must be configured to have TTL Propagation disabled.

CM-6 - Medium - CCI-000366 - V-78291 - SV-92997r1_rule

RMF Control

CM-6

Severity

CCI

Version

SRG-NET-000512-RTR-000004

Vuln IDs

V-78291

Rule IDs

SV-92997r1_rule

The head end of the label-switched path (LSP), the label edge router (LER) will decrement the IP packet's time-to-live (TTL) value by one and then copy the value to the MPLS TTL field. At each label-switched router (LSR) hop, the MPLS TTL value is decremented by one. The MPLS router that pops the label (either the penultimate LSR or the egress LER) will copy the packet's MPLS TTL value to the IP TTL field and decrement it by one. This TTL propagation is the default behavior. Because the MPLS TTL is propagated from the IP TTL, a traceroute will list every hop in the path, be it routed or label switched, thereby exposing core nodes. With TTL propagation disabled, LER decrements the IP packet's TTL value by one and then places a value of 255 in the packet's MPLS TTL field, which is then decremented by one as the packet passes through each LSR in the MPLS core. Because the MPLS TTL never drops to zero, none of the LSP hops triggers an ICMP TTL exceeded message and consequently, these hops are not recorded in a traceroute. Hence, nodes within the MPLS core cannot be discovered by an attacker.

Checks: C-77849r1_chk

Review the router configuration to verify that TTL propagation is disabled. If the router is not configured to disable TTL propagation, this is a finding.

Fix: F-85019r1_fix

Configure LERs to disable TTL propagation.

The PE router must be configured to have each Virtual Routing and Forwarding (VRF) instance bound to the appropriate physical or logical interfaces to maintain traffic separation between all MPLS L3VPNs.

CM-6 - High - CCI-000366 - V-78293 - SV-92999r1_rule

RMF Control

CM-6

Severity

CCI

Version

SRG-NET-000512-RTR-000005

Vuln IDs

V-78293

Rule IDs

SV-92999r1_rule

The primary security model for an MPLS VPN infrastructure is traffic separation. Each CE-facing interface can only be associated to one VRF; that alone is the fundamental framework for traffic separation. Once a packet from the connecting CE reaches the PE router, a forwarding decision is made based on the forwarding table belonging to the VRF. The next hop will always point to another PE. As the packet traverses the label-switched path (LSP) between the two PE routers, it is encapsulated with a VPN header - the inner MPLS label mapping to the associated VPN. The provider must guarantee the customer that data plane and control plane traffic from one VPN does not leak into another VPN or into the core, and that core traffic must not leak into any VPN. There is, however, the possibility of providing customer interconnections as well as the construction of an extranet to provide customers the ability to share common resources. Nevertheless, assuming correct operation and configuration of the MPLS core, the principles of separation prevail: VPNs are fully separated from each other so that intrusion from other VPNs or the core cannot occur. However, it is obvious that the greatest threat to the security model is human engineering; that is, misconfiguration of PE routers. For example, a customer-facing interface could be associated with the wrong VRF, prohibiting that site access to its proper VPN while providing access to another and vice versa.

Checks: C-77851r1_chk

Review the design plan for deploying L3VPN and VRF-lite. Review all CE-facing interfaces and verify that the proper VRF is defined. If any VRFs are not bound to the appropriate physical or logical interface, this is a finding.

Fix: F-85021r1_fix

Configure the PE router to have each VRF bound to the appropriate physical or logical interfaces to maintain traffic separation between all MPLS L3VPNs.

The PE router must be configured to have each Virtual Routing and Forwarding (VRF) instance with the appropriate Route Target (RT).

CM-6 - High - CCI-000366 - V-78295 - SV-93001r1_rule

RMF Control

CM-6

Severity

CCI

Version

SRG-NET-000512-RTR-000006

Vuln IDs

V-78295

Rule IDs

SV-93001r1_rule

The primary security model for an MPLS L3VPN as well as a VRF-lite infrastructure is traffic separation. Each interface can only be associated to one VRF, which is the fundamental framework for traffic separation. Forwarding decisions are made based on the routing table belonging to the VRF. Control of what routes are imported into or exported from a VRF is based on the RT. It is critical that traffic does not leak from one COI tenant or L3VPN to another; hence, it is imperative that the correct RT is configured for each VRF.

Checks: C-77853r1_chk

Verify that the correct RT is configured for each VRF. Review the design plan for MPLS/L3VPN and VRF-lite to determine what RTs have been assigned for each VRF. Review the route-target import, route-target, or route-target export statements under each configured VRF and verify that the correct RTs have been defined for each VRF. Note: Import and export route-maps are normally used when finer granularity is required. If there are VRFs configured with the wrong RT, this is a finding.

Fix: F-85023r1_fix

Configure all J-PE routers to have the correct VRF defined with the appropriate RT.

The PE router must be configured to have each VRF with the appropriate Route Distinguisher (RD).

CM-6 - Medium - CCI-000366 - V-78297 - SV-93003r1_rule

RMF Control

CM-6

Severity

CCI

Version

SRG-NET-000512-RTR-000007

Vuln IDs

V-78297

Rule IDs

SV-93003r1_rule

An RD provides uniqueness to the customer address spaces within the MPLS L3VPN infrastructure. The concept of the VPN-IPv4 and VPN-IPv6 address families consists of the RD prepended before the IP address. Hence, if the same IP prefix is used in several different L3VPNs, it is possible for BGP to carry several completely different routes for that prefix, one for each VPN. Since VPN-IPv4 addresses and IPv4 addresses are different address families, BGP never treats them as comparable addresses. The purpose of the RD is to create distinct routes for common IPv4 address prefixes. On any given PE router, a single RD can define a VRF in which the entire address space may be used independently, regardless of the makeup of other VPN address spaces. Hence, it is imperative that a unique RD is assigned to each L3VPN and that the proper RD is configured for each VRF.

Checks: C-77855r1_chk

Review the RDs that have been assigned for each VRF according to the plan provided by the ISSM. Review all VRFs configured on CE-facing interfaces and verify that the proper RD has been configured for each. If the wrong RD has been configured for any VRF, this is a finding.

Fix: F-85025r1_fix

Configure the correct RD for each VRF.

The PE router providing MPLS Layer 2 Virtual Private Network (L2VPN) services must be configured to authenticate targeted Label Distribution Protocol (LDP) sessions used to exchange virtual circuit (VC) information using a FIPS-approved message authentication code algorithm.

IA-3 - Medium - CCI-001958 - V-78299 - SV-93005r1_rule

RMF Control

IA-3

Severity

CCI

CCI-001958

Version

SRG-NET-000343-RTR-000001

Vuln IDs

V-78299

Rule IDs

SV-93005r1_rule

LDP provides the signaling required for setting up and tearing down pseudowires (virtual circuits used to transport Layer 2 frames) across an MPLS IP core network. Using a targeted LDP session, each PE router advertises a virtual circuit label mapping that is used as part of the label stack imposed on the frames by the ingress PE router during packet forwarding. Authentication provides protection against spoofed TCP segments that can be introduced into the LDP sessions.

Checks: C-77857r1_chk

Review the router configuration to determine if LDP messages are being authenticated for the targeted LDP sessions. If authentication is not being used for the LDP sessions using a FIPS-approved message authentication code algorithm, this is a finding.

Fix: F-85027r1_fix

Implement authentication for all targeted LDP sessions using a FIPS-approved message authentication code algorithm.

The PE router providing MPLS Virtual Private Wire Service (VPWS) must be configured to have the appropriate virtual circuit identification (VC ID) for each attachment circuit.

CM-6 - High - CCI-000366 - V-78301 - SV-93007r1_rule

RMF Control

CM-6

Severity

CCI

Version

SRG-NET-000512-RTR-000008

Vuln IDs

V-78301

Rule IDs

SV-93007r1_rule

VPWS is an L2VPN technology that provides a virtual circuit between two PE routers to forward Layer 2 frames between two customer-edge routers or switches through an MPLS-enabled IP core. The ingress PE router (virtual circuit head-end) encapsulates Ethernet frames inside MPLS packets using label stacking and forwards them across the MPLS network to the egress PE router (virtual circuit tail-end). During a virtual circuit setup, the J-PE routers exchange VC label bindings for the specified VC ID. The VC ID specifies a pseudowire associated with an ingress and egress PE router and the customer-facing attachment circuits. To guarantee that all frames are forwarded onto the correct pseudowire and to the correct customer and attachment circuits, it is imperative that the correct VC ID is configured for each attachment circuit.

Checks: C-77859r1_chk

Review the ingress and egress PE router configuration for each virtual circuit that has been provisioned. Verify that the correct and unique VCID has been configured for the appropriate attachment circuit. If the correct VC ID has not been configured on both routers, this is a finding. Note: Ethernet over MPLS in VLAN mode transports Ethernet traffic from a source 802.1Q VLAN to a destination 802.1Q VLAN over a core MPLS network. The VC ID must be unique and the same on each end as it is used to connect the endpoints of the VC.

Fix: F-85029r1_fix

Assign globally unique VC IDs for each virtual circuit and configure the attachment circuits with the appropriate VC ID. Configure the same VC ID on both ends of the VC.

The PE router providing Virtual Private LAN Services (VPLS) must be configured to have all attachment circuits defined to the virtual forwarding instance (VFI) with the globally unique VPN ID assigned for each customer VLAN.

CM-6 - High - CCI-000366 - V-78303 - SV-93009r1_rule

RMF Control

CM-6

Severity

CCI

Version

SRG-NET-000512-RTR-000009

Vuln IDs

V-78303

Rule IDs

SV-93009r1_rule

VPLS defines an architecture that delivers Ethernet multipoint services over an MPLS network. Customer Layer 2 frames are forwarded across the MPLS core via pseudowires using IEEE 802.1q Ethernet bridging principles. A pseudowire is a virtual bidirectional connection between two attachment circuits (virtual connections between PE and CE routers). A pseudowire contains two unidirectional label-switched paths (LSP) between two PE routers. Each MAC virtual forwarding table instance (VFI) is interconnected using pseudowires provisioned for the bridge domain, thereby maintaining privacy and logical separation between each VPLS bridge domain. The VFI specifies the pseudowires associated with connecting PE routers and the customer-facing attachment circuits belonging to a given VLAN. Resembling a Layer 2 switch, the VFI is responsible for learning MAC addresses and providing loop-free forwarding of customer traffic to the appropriate end nodes. Each VPLS domain is identified by a globally unique VPN ID; hence, VFIs of the same VPLS domain must be configured with the same VPN ID on all participating PE routers. To guarantee traffic separation for all customer VLANs and that all packets are forwarded to the correct destination, it is imperative that the correct attachment circuits are associated with the appropriate VFI and that each VFI is associated to the unique VPN ID assigned to the customer VLAN.

Checks: C-77861r1_chk

Review the implementation plan and the VPN IDs assigned to customer VLANs for the VPLS deployment. Review the PE router configuration to verify that customer attachment circuits (i.e., VLANs) are associated to the appropriate VFI. If the attachment circuits have not been bound to VFI configured with the assigned VPN ID for each VLAN, this is a finding.

Fix: F-85031r1_fix

Assign globally unique VPN IDs for each customer VLAN using VPLS for carrier Ethernet services between multiple sites, and configure the attachment circuits to the appropriate VFI.

The PE router must be configured to enforce the split-horizon rule for all pseudowires within a Virtual Private LAN Services (VPLS) bridge domain.

CM-6 - Low - CCI-000366 - V-78305 - SV-93011r1_rule

RMF Control

CM-6

Severity

CCI

Version

SRG-NET-000512-RTR-000010

Vuln IDs

V-78305

Rule IDs

SV-93011r1_rule

A virtual forwarding instance (VFI) must be created on each participating PE router for each customer VLAN using VPLS for carrier Ethernet services. The VFI specifies the VPN ID of a VPLS domain, the addresses of other PE routers in the domain, and the type of tunnel signaling and encapsulation mechanism for each peer PE router. The set of VFIs formed by the interconnection of the emulated VCs is called a VPLS instance, which forms the logic bridge over the MPLS core network. The PE routers use the VFI with a unique VPN ID to establish a full mesh of emulated virtual circuits or pseudowires to all the other PE routers in the VPLS instance. The full-mesh configuration allows the PE router to maintain a single broadcast domain. With a full-mesh configuration, signaling and packet replication requirements for each provisioned virtual circuit on a PE can be high. To avoid the problem of a packet looping in the provider core, thereby adding more overhead, the PE devices must enforce a split-horizon principle for the emulated virtual circuits; that is, if a packet is received on an emulated virtual circuit, it is not forwarded on any other virtual circuit.

Checks: C-77863r1_chk

Review the PE router configuration to verify that split horizon is enabled. If it is disabled, this is a finding. Note: In a ring VPLS, split horizon is disabled so that a PE router can forward a packet received from one pseudowire to another pseudowire. To prevent the consequential loop, at least one span in the ring would not have a pseudowire for any given VPLS instance.

Fix: F-85033r1_fix

Enable split horizon on all PE routers deploying VPLS in a full-mesh configuration.

The PE router providing Virtual Private LAN Services (VPLS) must be configured to have traffic storm control thresholds on CE-facing interfaces.

SC-5 - Medium - CCI-001095 - V-78307 - SV-93013r1_rule

RMF Control

SC-5

Severity

CCI

Version

SRG-NET-000193-RTR-000002

Vuln IDs

V-78307

Rule IDs

SV-93013r1_rule

A traffic storm occurs when packets flood a VPLS bridge, creating excessive traffic and degrading network performance. Traffic storm control prevents VPLS bridge disruption by suppressing traffic when the number of packets reaches configured threshold levels. Traffic storm control monitors incoming traffic levels on a port and drops traffic when the number of packets reaches the configured threshold level during any one-second interval.

Checks: C-77865r1_chk

Review the router configuration to verify that storm control is enabled on CE-facing interfaces deploying VPLS. If storm control is not enabled at a minimum for broadcast traffic, this is a finding. Note: The threshold level can be from 0 to 100 percent of the link's bandwidth, where "0" suppresses all traffic. Most FastEthernet switching modules do not support multicast and unicast traffic storm control.

Fix: F-85035r1_fix

Configure storm control for each VPLS bridge domain. Base the suppression threshold on expected traffic rates plus some additional capacity. For example, if the peak broadcast traffic that is acceptable for a port is 10 percent, a threshold of 15 percent might be appropriate.

The PE router must be configured to implement Internet Group Management Protocol (IGMP) or Multicast Listener Discovery (MLD) snooping for each Virtual Private LAN Services (VPLS) bridge domain.

SC-5 - Low - CCI-002385 - V-78309 - SV-93015r1_rule

RMF Control

SC-5

Severity

CCI

Version

SRG-NET-000362-RTR-000119

Vuln IDs

V-78309

Rule IDs

SV-93015r1_rule

IGMP snooping provides a way to constrain multicast traffic at Layer 2. By monitoring the IGMP membership reports sent by hosts within the bridge domain, the snooping application can set up Layer 2 multicast forwarding tables to deliver traffic only to ports with at least one interested member within the VPLS bridge, thereby significantly reducing the volume of multicast traffic that would otherwise flood an entire VPLS bridge domain. The IGMP snooping operation applies to both access circuits and pseudowires within a VPLS bridge domain.

Checks: C-77867r1_chk

Review the router configuration to verify that IGMP or MLD snooping has been configured for IPv4 and IPv6 multicast traffic respectively for each VPLS bridge domain (VFI instance). If the router is not configured to implement IGMP or MLD snooping for each VPLS bridge domain, this is a finding.

Fix: F-85037r1_fix

Configure IGMP or MLD snooping for IPv4 and IPv6 multicast traffic respectively for each VPLS bridge domain.

The PE router must be configured to limit the number of MAC addresses it can learn for each Virtual Private LAN Services (VPLS) bridge domain.

SC-5 - Medium - CCI-001094 - V-78311 - SV-93017r1_rule

RMF Control

SC-5

Severity

CCI

CCI-001094

Version

SRG-NET-000192-RTR-000002

Vuln IDs

V-78311

Rule IDs

SV-93017r1_rule

VPLS defines an architecture that delivers Ethernet multipoint services over an MPLS network. Customer Layer 2 frames are forwarded across the MPLS core via pseudowires using IEEE 802.1q Ethernet bridging principles. A pseudowire is a virtual bidirectional connection between two attachment circuits (virtual connections between PE and CE routers). A pseudowire contains two unidirectional label-switched paths (LSP). Each MAC forwarding table instance is interconnected using domain-specific LSPs, thereby maintaining privacy and logical separation between each VPLS domain. When a frame arrives on a bridge port (pseudowire or attachment circuit) and the source MAC address is unknown to the receiving PE router, the source MAC address is associated with the pseudowire or attachment circuit and the forwarding table is updated accordingly. Frames are forwarded to the appropriate pseudowire or attachment circuit according to the forwarding table entry for the destination MAC address. Ethernet frames sent to broadcast and unknown destination addresses must be flooded out to all interfaces for the bridge domain; hence, a PE router must replicate packets across both attachment circuits and pseudowires. A malicious attacker residing in a customer network could launch a source MAC address spoofing attack by flooding packets to a valid unicast destination, each with a different MAC source address. The PE router receiving this traffic would try to learn every new MAC address and would quickly run out of space for the VFI forwarding table. Older, valid MAC addresses would be removed from the table, and traffic sent to them would have to be flooded until the storm threshold limit is reached. Hence, it is essential that a limit is established to control the number of MAC addresses that will be learned and recorded into the forwarding table for each bridge domain.

Checks: C-77869r1_chk

Review the PE router configuration to determine if a MAC address limit has been set for each bridge domain. If a limit has not been configured, this is a finding.

Fix: F-85039r1_fix

Configure a MAC address learning limit for each VPLS bridge domain.

The PE router must be configured to block any traffic that is destined to IP core infrastructure.

SC-7 - High - CCI-001097 - V-78313 - SV-93019r1_rule

RMF Control

SC-7

Severity

CCI

Version

SRG-NET-000205-RTR-000007

Vuln IDs

V-78313

Rule IDs

SV-93019r1_rule

IP/MPLS networks providing VPN and transit services must provide, at the least, the same level of protection against denial-of-service (DoS) attacks and intrusions as Layer 2 networks. Although the IP core network elements are hidden, security should never rely entirely on obscurity. IP addresses can be guessed. Core network elements must not be accessible from any external host. Protecting the core from any attack is vital for the integrity and privacy of customer traffic as well as the availability of transit services. A compromise of the IP core can result in an outage or, at a minimum, non-optimized forwarding of customer traffic. Protecting the core from an outside attack also prevents attackers from using the core to attack any customer. Hence, it is imperative that all routers at the edge deny traffic destined to any address belonging to the IP core infrastructure.

Checks: C-77871r1_chk

Review the router configuration to verify that an ingress ACL is applied to all CE-facing interfaces. Verify that the ingress ACL rejects and logs packets destined to the IP core address block. If the PE router is not configured to block any traffic with a destination address assigned to the IP core infrastructure, this is a finding. Note: Internet Control Message Protocol (ICMP) echo requests and traceroutes will be allowed to the edge from external adjacent peers.

Fix: F-85041r1_fix

Configure protection for the IP core to be implemented at the edges by blocking any traffic with a destination address assigned to the IP core infrastructure.

The PE router must be configured with Unicast Reverse Path Forwarding (RPF) loose mode on all CE-facing interfaces.

SC-7 - Medium - CCI-001097 - V-78315 - SV-93021r1_rule

RMF Control

SC-7

Severity

CCI

Version

SRG-NET-000205-RTR-000008

Vuln IDs

V-78315

Rule IDs

SV-93021r1_rule

The uRPF feature is a defense against spoofing and denial-of-service (DoS) attacks by verifying if the source address of any ingress packet is reachable. To mitigate attacks that rely on forged source addresses, all provider edge routers must enable uRPF loose mode to guarantee that all packets received from a CE router contain source addresses that are in the route table.

Checks: C-77873r1_chk

Review the router configuration to determine if uRPF loose mode is enabled on all CE-facing interfaces. If uRPF loose mode is not enabled on all CE-facing interfaces, this is a finding.

Fix: F-85043r1_fix

Enable uRPF loose mode on all CE-facing interfaces.

The PE router must be configured to ignore or block all packets with any IP options.

SC-7 - Medium - CCI-002403 - V-78317 - SV-93023r1_rule

RMF Control

SC-7

Severity

CCI

Version

SRG-NET-000195-RTR-000085

Vuln IDs

V-78317

Rule IDs

SV-93023r1_rule

Packets with IP options are not fast switched and therefore must be punted to the router processor. Hackers who initiate denial-of-service (DoS) attacks on routers commonly send large streams of packets with IP options. Dropping the packets with IP options reduces the load of IP options packets on the router. The end result is a reduction in the effects of the DoS attack on the router and on downstream routers.

Checks: C-77875r1_chk

Review the router configuration to determine if it will block all packets with IP options. If the router is not configured to drop all packets with IP options, this is a finding.

Fix: F-85045r1_fix

Configure the router to drop all packets with IP options.

The PE router must be configured to enforce a Quality-of-Service (QoS) policy in accordance with the QoS DoDIN Technical Profile.

SC-5 - Low - CCI-001095 - V-78319 - SV-93025r1_rule

RMF Control

SC-5

Severity

CCI

Version

SRG-NET-000193-RTR-000113

Vuln IDs

V-78319

Rule IDs

SV-93025r1_rule

Different applications have unique requirements and toleration levels for delay, jitter, bandwidth, packet loss, and availability. To manage the multitude of applications and services, a network requires a QoS framework to differentiate traffic and provide a method to manage network congestion. The Differentiated Services Model (DiffServ) is based on per-hop behavior by categorizing traffic into different classes and enabling each node to enforce a forwarding treatment to each packet as dictated by a policy. Packet markings such as IP Precedence and its successor, Differentiated Services Code Points (DSCP), were defined along with specific per-hop behaviors for key traffic types to enable a scalable QoS solution. DiffServ QoS categorizes network traffic, prioritizes it according to its relative importance, and provides priority treatment based on the classification. It is imperative that end-to-end QoS is implemented within the IP core network to provide preferred treatment for mission-critical applications.

Checks: C-77877r1_chk

Review the router configuration and verify that a QoS policy has been configured to provide preferred treatment for mission-critical applications in accordance with the QoS DoDIN Technical Profile. Verify that the class-maps are configured to match on DSCP, protocols, or access control lists (ACLs) that identify traffic types based on ports. Verify that the policy-map is configured to set DSCP values for the defined class-maps in accordance with the QoS DoDIN Technical Profile. Verify that an input service policy is bound to all CE-facing interfaces. If the router is not configured to enforce a QoS policy in accordance with the QoS DoDIN Technical Profile, this is a finding.

Fix: F-85047r1_fix

Configure a QoS policy on each router in accordance with the QoS DoDIN Technical Profile.

The PE or P router must be configured to implement a Quality-of-Service (QoS) policy in accordance with the QoS DoDIN Technical Profile.

SC-5 - Low - CCI-001095 - V-78321 - SV-93027r1_rule

RMF Control

SC-5

Severity

CCI

Version

SRG-NET-000193-RTR-000114

Vuln IDs

V-78321

Rule IDs

SV-93027r1_rule

Checks: C-77879r1_chk

Review the router configuration and verify that a QoS policy has been configured to provide preferred treatment for mission-critical applications in accordance with the QoS DoDIN Technical Profile. Verify that the class-maps are configured to match on DSCP values that have been set at the edges. Verify that the policy map is configured to reserve the bandwidth for each traffic type as specified via the class-maps. Verify that an output service policy is bound to all interfaces. If the router is not configured to implement a QoS policy in accordance with the QoS DoDIN Technical Profile, this is a finding.

Fix: F-85049r1_fix

Configure a QoS policy on each router in accordance with the QoS DoDIN Technical Profile.

The PE router must be configured to enforce a Quality-of-Service (QoS) policy so that all customer traffic receives forwarding treatment as specified in the service level agreement (SLA).

SC-5 - Medium - CCI-001095 - V-78323 - SV-93029r1_rule

RMF Control

SC-5

Severity

CCI

Version

SRG-NET-000193-RTR-000109

Vuln IDs

V-78323

Rule IDs

SV-93029r1_rule

QoS enables DISA to offer value-added IP services in accordance with SLAs, ensuring that customer requirements can be met while providing a method to provision the edge and core to accommodate those requirements. The IP core will recognize and provide forwarding treatment of customer traffic according to the Differentiated Services Code Points (DSCP). Customers marking traffic within their DiffServ domain will be required to comply with the DSCP classification that has been approved by the DOD QoS Working Group. Non-compliance could enable a customer or even an attacker to rob bandwidth from other customers or mission-critical services.

Checks: C-77881r1_chk

Review the router configuration verify that the class-maps are configured to match on DSCP, protocols, or access control lists (ACLs) that identify traffic types based on ports. Verify that the policy-map is configured to set DSCP values for the defined class-maps in accordance with the customer SLA. Verify that an input service policy is bound to all CE-facing interfaces. If the PE router does not enforce a QoS policy to ensure that all customer traffic receives forwarding treatment as specified in the SLA, this is a finding.

Fix: F-85051r1_fix

The ISSM will ensure QoS policies are configured on all the PE routers so all customer traffic receives forwarding treatment as specified in the SLA.

The router must be configured to enforce a Quality-of-Service (QoS) policy to limit the effects of packet flooding denial-of-service (DoS) attacks.

SC-5 - Medium - CCI-001095 - V-78325 - SV-93031r1_rule

RMF Control

SC-5

Severity

CCI

Version

SRG-NET-000193-RTR-000112

Vuln IDs

V-78325

Rule IDs

SV-93031r1_rule

DoS is a condition when a resource is not available for legitimate users. Packet flooding distributed denial-of-service (DDoS) attacks are referred to as volumetric attacks and have the objective of overloading a network or circuit to deny or seriously degrade performance, which denies access to the services that normally traverse the network or circuit. Volumetric attacks have become relatively easy to launch using readily available tools such as Low Orbit Ion Cannon or botnets. Measures to mitigate the effects of a successful volumetric attack must be taken to ensure that sufficient capacity is available for mission-critical traffic. Managing capacity may include, for example, establishing selected network usage priorities or quotas and enforcing them using rate limiting, Quality of Service (QoS), or other resource reservation control methods. These measures may also mitigate the effects of sudden decreases in network capacity that are the result of accidental or intentional physical damage to telecommunications facilities (such as cable cuts or weather-related outages).

Checks: C-77883r1_chk

Review the router configuration and interview the System Administrator to verify that a mechanism for traffic prioritization and bandwidth reservation exists. This arrangement must ensure that sufficient capacity is available for mission-critical traffic and enforce the traffic priorities specified by the Combatant Commands/Services/Agencies. If no such scheme exists or it is not configured, this is a finding.

Fix: F-85053r1_fix

Implement a mechanism for traffic prioritization and bandwidth reservation. This mechanism must enforce the traffic priorities specified by the Combatant Commands/Services/Agencies.

The multicast Rendezvous Point (RP) router must be configured to limit the multicast forwarding cache so that its resources are not saturated by managing an overwhelming number of Protocol Independent Multicast (PIM) and Multicast Source Discovery Protocol (MSDP) source-active entries.

SC-5 - Low - CCI-002385 - V-78327 - SV-93033r1_rule

RMF Control

SC-5

Severity

CCI

Version

SRG-NET-000362-RTR-000120

Vuln IDs

V-78327

Rule IDs

SV-93033r1_rule

MSDP peering between networks enables sharing of multicast source information. Enclaves with an existing multicast topology using PIM-SM can configure their RP routers to peer with MSDP routers. As a first step of defense against a denial-of-service (DoS) attack, all RP routers must limit the multicast forwarding cache to ensure that router resources are not saturated managing an overwhelming number of PIM and MSDP source-active entries.

Checks: C-77885r1_chk

Review the router configuration to determine if forwarding cache thresholds are defined. If the RP router is not configured to limit the multicast forwarding cache to ensure that its resources are not saturated, this is a finding.

Fix: F-85055r1_fix

Configure MSDP-enabled RP routers to limit the multicast forwarding cache for source-active entries.

The multicast Designated Router (DR) must be configured to rate limit the number of Protocol Independent Multicast (PIM) Register messages it will allow for each source-group (S, G) entry.

SC-5 - Medium - CCI-002385 - V-78329 - SV-93035r1_rule

RMF Control

SC-5

Severity

CCI

Version

SRG-NET-000362-RTR-000121

Vuln IDs

V-78329

Rule IDs

SV-93035r1_rule

When a new source starts transmitting in a PIM Sparse Mode network, the DR will encapsulate the multicast packets into register messages and forward them to the RP using unicast. This process can be taxing on the CPU for both the DR and the RP if the source is running at a high data rate and there are many new sources starting at the same time. This scenario can potentially occur immediately after a network failover. The rate limit for the number of register messages should be set to a relatively low value based on the known number of multicast sources within the multicast domain.

Checks: C-77887r1_chk

Review the configuration of the DR to verify that it is rate limiting the number of multicast register messages. If the DR is not limiting multicast register messages, this is a finding.

Fix: F-85057r1_fix

Configure the DR to rate limit the number of multicast register messages it will allow for each (S, G) entry.

The multicast Designated Router (DR) must be configured to filter the Internet Group Management Protocol (IGMP) and Multicast Listener Discovery (MLD) Report messages to allow hosts to join only multicast groups that have been approved by the organization.

SC-7 - Low - CCI-002403 - V-78331 - SV-93037r1_rule

RMF Control

SC-7

Severity

CCI

Version

SRG-NET-000364-RTR-000114

Vuln IDs

V-78331

Rule IDs

SV-93037r1_rule

Real-time multicast traffic can entail multiple large flows of data. Large unicast flows tend to be fairly isolated (i.e., someone doing a file download here or there), whereas multicast can have broader impact on bandwidth consumption, resulting in extreme network congestion. Hence, it is imperative that there is multicast admission control to restrict which multicast groups hosts are allowed to join via IGMP or MLD.

Checks: C-77889r1_chk

Review the configuration of the DR to verify that it is filtering IGMP or MLD report messages, allowing hosts to join only those groups that have been approved. If the DR is not filtering IGMP or MLD report messages, this is a finding.

Fix: F-85059r1_fix

Configure the DR to filter the IGMP and MLD report messages to allow hosts to join only those multicast groups that have been approved.

The multicast Designated Router (DR) must be configured to filter the Internet Group Management Protocol (IGMP) and Multicast Listener Discovery (MLD) Report messages to allow hosts to join a multicast group only from sources that have been approved by the organization.

SC-7 - Medium - CCI-002403 - V-78333 - SV-93039r1_rule

RMF Control

SC-7

Severity

CCI

Version

SRG-NET-000364-RTR-000115

Vuln IDs

V-78333

Rule IDs

SV-93039r1_rule

Checks: C-77893r1_chk

Review the configuration of the DR to verify that it is filtering IGMP or MLD report messages, allowing hosts to only join multicast groups from sources that have been approved. If the DR is not filtering IGMP or MLD report messages, this is a finding.

Fix: F-85063r1_fix

Configure the DR to filter the IGMP and MLD report messages to allow hosts to join only those multicast groups from sources that have been approved.

The multicast Designated Router (DR) must be configured to limit the number of mroute states resulting from Internet Group Management Protocol (IGMP) and Multicast Listener Discovery (MLD) Host Membership Reports.

SC-5 - Medium - CCI-002385 - V-78335 - SV-93041r1_rule

RMF Control

SC-5

Severity

CCI

Version

SRG-NET-000362-RTR-000122

Vuln IDs

V-78335

Rule IDs

SV-93041r1_rule

The current multicast paradigm can let any host join any multicast group at any time by sending an IGMP or MLD membership report to the DR. In a Protocol Independent Multicast (PIM) Sparse Mode network, the DR will send a PIM Join message for the group to the RP. Without any form of admission control, this can pose a security risk to the entire multicast domain - specifically the multicast routers along the shared tree from the DR to the RP that must maintain the mroute state information for each group join request. Hence, it is imperative that the DR is configured to limit the number of mroute state information that must be maintained to mitigate the risk of IGMP or MLD flooding.

Checks: C-77895r1_chk

Review the DR configuration to verify that it is limiting the number of mroute states via IGMP or MLD. If the DR is not limiting multicast join requests via IGMP or MLD, this is a finding. Note: If both global and per-interface state limiters are configured, the limits configured for per-interface state limiters are still enforced but are constrained by the global limit.

Fix: F-85065r1_fix

Configure the DR on a global or interface basis to limit the number of mroute states resulting from IGMP or MLD membership reports.

The multicast Designated Router (DR) must be configured to increase the shortest-path tree (SPT) threshold or set it to infinity to minimalize source-group (S, G) state within the multicast topology where Any Source Multicast (ASM) is deployed.

SC-5 - Medium - CCI-002385 - V-78337 - SV-93043r1_rule

RMF Control

SC-5

Severity

CCI

Version

SRG-NET-000362-RTR-000123

Vuln IDs

V-78337

Rule IDs

SV-93043r1_rule

ASM can have many sources for the same groups (many-to-many). For many receivers, the path via the RP may not be ideal compared with the shortest path from the source to the receiver. By default, the last-hop router will initiate a switch from the shared tree to a source-specific SPT to obtain lower latencies. This is accomplished by the last-hop router sending an (S, G) Protocol Independent Multicast (PIM) Join toward S (the source). When the last-hop router begins to receive traffic for the group from the source via the SPT, it will send a PIM Prune message to the RP for the (S, G). The RP will then send a Prune message toward the source. The SPT switchover becomes a scaling issue for large multicast topologies that have many receivers and many sources for many groups because (S, G) entries require more memory than (*, G). Hence, it is imperative to minimize the amount of (S, G) state to be maintained by increasing the threshold that determines when the SPT switchover occurs.

Checks: C-77897r1_chk

Review the multicast last-hop router configuration to verify that the SPT switchover threshold is increased (default is "0") or set to infinity (never switch over). If any multicast router is not configured to increase the SPT threshold or set to infinity to minimalize (S, G) state, this is a finding.

Fix: F-85067r1_fix

Configure the multicast router to increase the SPT threshold or set it to infinity to minimalize (S, G) state within the multicast topology where ASM is deployed.

The Multicast Source Discovery Protocol (MSDP) router must be configured to only accept MSDP packets from known MSDP peers.

SC-7 - Medium - CCI-002403 - V-78339 - SV-93045r1_rule

RMF Control

SC-7

Severity

CCI

Version

SRG-NET-000364-RTR-000116

Vuln IDs

V-78339

Rule IDs

SV-93045r1_rule

MSDP peering with customer network routers presents additional risks to the DISN Core, whether from a rogue or misconfigured MSDP-enabled router. To guard against an attack from malicious MSDP traffic, the receive path or interface filter for all MSDP-enabled RP routers must be configured to only accept MSDP packets from known MSDP peers.

Checks: C-77899r1_chk

Review the router configuration to determine if there is a receive path or interface filter to only accept MSDP packets from known MSDP peers. If the router is not configured to only accept MSDP packets from known MSDP peers, this is a finding.

Fix: F-85069r1_fix

Ensure the receive path or interface filter for all MSDP routers only accepts MSDP packets from known MSDP peers.

The Multicast Source Discovery Protocol (MSDP) router must be configured to authenticate all received MSDP packets.

IA-3 - Medium - CCI-001958 - V-78341 - SV-93047r1_rule

RMF Control

IA-3

Severity

CCI

CCI-001958

Version

SRG-NET-000343-RTR-000002

Vuln IDs

V-78341

Rule IDs

SV-93047r1_rule

MSDP peering with customer network routers presents additional risks to the core, whether from a rogue or misconfigured MSDP-enabled router. MSDP password authentication is used to validate each segment sent on the TCP connection between MSDP peers, protecting the MSDP session against the threat of spoofed packets being injected into the TCP connection stream.

Checks: C-77901r1_chk

Review the router configuration to determine if received MSDP packets are authenticated. If the router does not require MSDP authentication, this is a finding.

Fix: F-85071r1_fix

Ensure all MSDP packets received by an MSDP router are authenticated.

The Multicast Source Discovery Protocol (MSDP) router must be configured to filter received source-active multicast advertisements for any undesirable multicast groups (e.g., auto-RP, source-specific, link-local, black listed, etc.) and Bogon sources.

AC-4 - Low - CCI-001368 - V-78343 - SV-93049r1_rule

RMF Control

AC-4

Severity

CCI

Version

SRG-NET-000018-RTR-000007

Vuln IDs

V-78343

Rule IDs

SV-93049r1_rule

The interoperability of BGP extensions for interdomain multicast routing and MSDP enables seamless connectivity of multicast domains between autonomous systems. MP-BGP advertises the unicast prefixes of the multicast sources used by Protocol Independent Multicast (PIM) routers to perform RPF checks and build multicast distribution trees. MSDP is a mechanism used to connect multiple PIM sparse-mode domains, allowing RPs from different domains to share information about active sources. When RPs in peering multicast domains hear about active sources, they can pass on that information to their local receivers, thereby allowing multicast data to be forwarded between the domains. Configuring an import policy to block multicast advertisements for reserved, martian, single-source multicast, and any other undesirable multicast groups, as well as any source-group (S, G) states with Bogon source addresses, would assist in avoiding unwanted multicast traffic from traversing the core.

Checks: C-77903r1_chk

Review the router configuration to determine if there is import policy to block source-active multicast advertisements for reserved, Martian, single-source multicast, and any other undesirable multicast groups, as well as any (S, G) states with Bogon source addresses. Verify that an inbound source-active filter is bound to each MSDP peer. Review the access lists referenced by the source-active filter to verify that bad multicast groups, auto-RP, single source multicast (SSM) groups, and advertisements from Bogon sources are blocked. If the router is not configured with an import policy to block undesirable SA multicast advertisements, this is a finding.

Fix: F-85073r1_fix

Ensure all MSDP routers implement an import policy to block multicast advertisements for reserved, martian, single-source multicast, and any other undesirable multicast groups, as well as any (S, G) states with Bogon source addresses.

The Multicast Source Discovery Protocol (MSDP) router must be configured to filter source-active multicast advertisements to external MSDP peers to avoid global visibility of local-only multicast sources and groups.

AC-4 - Low - CCI-001368 - V-78345 - SV-93051r1_rule

RMF Control

AC-4

Severity

CCI

Version

SRG-NET-000018-RTR-000008

Vuln IDs

V-78345

Rule IDs

SV-93051r1_rule

To avoid global visibility of local information, there are a number of source-group (S, G) states in a PIM-SM domain that must not be leaked to another domain, such as multicast sources with private address, administratively scoped multicast addresses, and the auto-RP groups (224.0.1.39 and 224.0.1.40). Allowing a multicast distribution tree, local to the core, to extend beyond its boundary could enable local multicast traffic to leak into other autonomous systems and customer networks.

Checks: C-77905r1_chk

Review the router configuration to determine if there is export policy to block local source-active multicast advertisements. Verify that an outbound source-active filter is bound to each MSDP peer. Review the access lists referenced by the source-active filters and verify that MSDP source-active messages being sent to MSDP peers do not leak advertisements that are local. If the router is not configured with an export policy to block local source-active multicast advertisements, this is a finding.

Fix: F-85075r1_fix

Ensure an export policy is implemented on all MSDP routers to avoid global visibility of local multicast (S, G) states.

The MSDP router must be configured to limit the amount of source-active messages it accepts on per-peer basis.

AC-4 - Low - CCI-001368 - V-78347 - SV-93053r1_rule

RMF Control

AC-4

Severity

CCI

Version

SRG-NET-000018-RTR-000009

Vuln IDs

V-78347

Rule IDs

SV-93053r1_rule

To reduce any risk of a denial-of-service (DoS) attack from a rogue or misconfigured MSDP router, the router must be configured to limit the number of source-active messages it accepts from each peer.

Checks: C-77907r1_chk

Review the router configuration to determine if it is configured to limit the amount of source-active messages it accepts on a per-peer basis. If the router is not configured to limit the source-active messages it accepts, this is a finding.

Fix: F-85077r1_fix

Configure the MSDP router to limit the amount of source-active messages it accepts from each peer.

The Multicast Source Discovery Protocol (MSDP) router must be configured to use its loopback address as the source address when originating MSDP traffic.

CM-6 - Low - CCI-000366 - V-78349 - SV-93055r1_rule

RMF Control

CM-6

Severity

CCI

Version

SRG-NET-000512-RTR-000011

Vuln IDs

V-78349

Rule IDs

SV-93055r1_rule

Using a loopback address as the source address offers a multitude of uses for security, access, management, and scalability of MSDP routers. It is easier to construct appropriate ingress filters for router management plane traffic destined to the network management subnet since the source addresses will be from the range used for loopback interfaces instead of a larger range of addresses used for physical interfaces. Log information recorded by authentication and syslog servers will record the router’s loopback address instead of the numerous physical interface addresses.

Checks: C-77909r1_chk

Review the router configuration to verify that a loopback address has been configured. Verify that a loopback interface is used as the source address for all MSDP packets generated by the router. If the router does not use its loopback address as the source address when originating MSDP traffic, this is a finding.

Fix: F-85079r1_fix

Ensure that the router’s loopback address is used as the source address when originating traffic.

The router must be configured to only permit management traffic that ingresses and egresses the OOBM interface.

SC-7 - Medium - CCI-001097 - V-78351 - SV-93057r1_rule

RMF Control

SC-7

Severity

CCI

Version

SRG-NET-000205-RTR-000012

Vuln IDs

V-78351

Rule IDs

SV-93057r1_rule

The OOBM access switch will connect to the management interface of the managed network elements. The management interface can be a true OOBM interface or a standard interface functioning as the management interface. In either case, the management interface of the managed network element will be directly connected to the OOBM network. An OOBM interface does not forward transit traffic, thereby providing complete separation of production and management traffic. Since all management traffic is immediately forwarded into the management network, it is not exposed to possible tampering. The separation also ensures that congestion or failures in the managed network do not affect the management of the device. If the device does not have an OOBM port, the interface functioning as the management interface must be configured so that management traffic does not leak into the managed network and that production traffic does not leak into the management network.

Checks: C-77911r1_chk

Step 1: Verify that the managed interface has an inbound and outbound ACL configured. Step 2: Verify that the ingress ACL blocks all transit traffic—that is, any traffic not destined to the router itself. In addition, traffic accessing the managed router should be originated at the NOC. Note that the destination used by any host within the management network to access the managed router must be via the management interface. The loopback should not be a valid address since these prefixes would not be advertised into the management network IGP domain. This could only be possible if the managed network elements had an IGP adjacency with the managed network, which should not be the case. Step 3: Verify that the egress ACL blocks any traffic not originated by the managed router. In addition, traffic egressing the management interface must be destined to the NOC. Caveat: This requirement is only applicable if the management interface connected to the OOBM access switch is a routed interface. If the management interface is a true OOBM interface, this requirement is not applicable. If the router does not restrict traffic that ingresses and egresses the management interface, this is a finding.

Fix: F-85081r1_fix

If the management interface is a routed interface, it must be configured with both an ingress and egress ACL. The ingress ACL should block any transit traffic, while the egress ACL should block any traffic that was not originated by the managed network device.

The out-of-band management (OOBM) gateway router must be configured to block any traffic destined to itself that is not sourced from the OOBM network or the NOC.

SC-7 - Medium - CCI-001097 - V-78357 - SV-93063r1_rule

RMF Control

SC-7

Severity

CCI