Cisco IOS Switch L2S Security Technical Implementation Guide

Description

This Security Technical Implementation Guide is published as a tool to improve the security of Department of Defense (DoD) information systems. The requirements are derived from the National Institute of Standards and Technology (NIST) 800-53 and related documents. Comments or proposed revisions to this document should be sent via email to the following address: [email protected]

Details

Version / Release: V2R1

Published: 2021-03-26

Updated At: 2021-05-02 20:53:42

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Drop CKL or SCAP (XCCDF) results here.

    Vuln Rule Version CCI Severity Title Description Status Finding Details Comments
    SV-220622r539671_rule CISC-L2-000010 CCI-000381 MEDIUM The Cisco switch must be configured to disable non-essential capabilities. A compromised switch 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
    SV-220623r539671_rule CISC-L2-000020 CCI-000778 HIGH The Cisco switch must uniquely identify all network-connected endpoint devices before establishing any connection. Controlling LAN access via 802.1x authentication can assist in preventing a malicious user from connecting an unauthorized PC to a switch port to inject or receive data from the network without detection.
    SV-220624r539671_rule CISC-L2-000030 CCI-000803 MEDIUM The Cisco switch must authenticate all VLAN Trunk Protocol (VTP) messages with a hash function using the most secured cryptographic algorithm available. VTP provides central management of VLAN domains, thus reducing administration in a switched network. When configuring a new VLAN on a VTP server, the VLAN is distributed through all switches in the domain. This reduces the need to configure the same VLAN
    SV-220625r539671_rule CISC-L2-000040 CCI-001095 MEDIUM The Cisco switch must manage excess bandwidth to limit the effects of packet-flooding types of denial-of-service (DoS) attacks. Denial of service is a condition when a resource is not available for legitimate users. Packet-flooding DDoS attacks are referred to as volumetric attacks and have the objective of overloading a network or circuit to deny or seriously degrade performance,
    SV-220626r539671_rule CISC-L2-000060 CCI-001919 MEDIUM The Cisco switch must be configured for authorized users to select a user session to capture. Without the capability to select a user session to capture/record or view/hear, investigations into suspicious or harmful events would be hampered by the volume of information captured. The volume of information captured may also adversely impact the oper
    SV-220627r539671_rule CISC-L2-000070 CCI-001920 MEDIUM The Cisco switch must be configured for authorized users to remotely view, in real time, all content related to an established user session from a component separate from the Cisco switch. Without the capability to remotely view/hear all content related to a user session, investigations into suspicious user activity would be hampered. Real-time monitoring allows authorized personnel to take action before additional damage is done. The abili
    SV-220628r539671_rule CISC-L2-000080 CCI-001958 MEDIUM The Cisco switch must authenticate all endpoint devices before establishing any connection. Without authenticating devices, unidentified or unknown devices may be introduced, thereby facilitating malicious activity. For distributed architectures (e.g., service-oriented architectures), the decisions regarding the validation of authentication cla
    SV-220629r539671_rule CISC-L2-000090 CCI-002385 LOW The Cisco switch must have Root Guard enabled on all switch ports connecting to access layer switches and hosts. Spanning Tree Protocol (STP) does not provide any means for the network administrator to securely enforce the topology of the switched network. Any switch can be the root bridge in a network. However, a more optimal forwarding topology places the root bri
    SV-220630r539671_rule CISC-L2-000100 CCI-002385 MEDIUM The Cisco switch must have Bridge Protocol Data Unit (BPDU) Guard enabled on all user-facing or untrusted access switch ports. If a rogue switch is introduced into the topology and transmits a BPDU with a lower bridge priority than the existing root bridge, it will become the new root bridge and cause a topology change, rendering the network in a suboptimal state. The STP PortFa
    SV-220631r539671_rule CISC-L2-000110 CCI-002385 MEDIUM The Cisco switch must have Spanning Tree Protocol (STP) Loop Guard enabled. The STP loop guard feature provides additional protection against STP loops. An STP loop is created when an STP blocking port in a redundant topology erroneously transitions to the forwarding state. In its operation, STP relies on continuous reception and
    SV-220632r539671_rule CISC-L2-000120 CCI-002385 MEDIUM The Cisco switch must have Unknown Unicast Flood Blocking (UUFB) enabled. Access layer switches use the Content Addressable Memory (CAM) table to direct traffic to specific ports based on the VLAN number and the destination MAC address of the frame. When a router has an Address Resolution Protocol (ARP) entry for a destination
    SV-220633r539671_rule CISC-L2-000130 CCI-002385 MEDIUM The Cisco switch must have DHCP snooping for all user VLANs to validate DHCP messages from untrusted sources. In an enterprise network, devices under administrative control are trusted sources. These devices include the switches, routers, and servers in the network. Host ports and unknown DHCP servers are considered untrusted sources. An unknown DHCP server on th
    SV-220634r539671_rule CISC-L2-000140 CCI-002385 MEDIUM The Cisco switch must have IP Source Guard enabled on all user-facing or untrusted access switch ports. IP Source Guard provides source IP address filtering on a Layer 2 port to prevent a malicious host from impersonating a legitimate host by assuming the legitimate host's IP address. The feature uses dynamic DHCP snooping and static IP source binding to ma
    SV-220635r539671_rule CISC-L2-000150 CCI-002385 MEDIUM The Cisco switch must have Dynamic Address Resolution Protocol (ARP) Inspection (DAI) enabled on all user VLANs. DAI intercepts ARP requests and verifies that each of these packets has a valid IP-to-MAC address binding before updating the local ARP cache and before forwarding the packet to the appropriate destination. Invalid ARP packets are dropped and logged. DA
    SV-220636r648763_rule CISC-L2-000160 CCI-000366 LOW The Cisco switch must have Storm Control configured on all host-facing switchports. A traffic storm occurs when packets flood a LAN, creating excessive traffic and degrading network performance. Traffic storm control prevents network disruption by suppressing ingress traffic when the number of packets reaches a configured threshold level
    SV-220637r539671_rule CISC-L2-000170 CCI-000366 LOW The Cisco switch must have IGMP or MLD Snooping configured on all VLANs. IGMP and MLD snooping provide a way to constrain multicast traffic at Layer 2. By monitoring the IGMP or MLD membership reports sent by hosts within a VLAN, the snooping application can set up Layer 2 multicast forwarding tables to deliver specific multic
    SV-220638r539671_rule CISC-L2-000180 CCI-000366 MEDIUM The Cisco switch must implement Rapid Spanning Tree Protocol (STP) where VLANs span multiple switches with redundant links. STP is implemented on bridges and switches to prevent Layer 2 loops when a broadcast domain spans multiple bridges and switches and when redundant links are provisioned to provide high availability in case of link failures. Convergence time can be signi
    SV-220639r539671_rule CISC-L2-000190 CCI-000366 MEDIUM The Cisco switch must enable Unidirectional Link Detection (UDLD) to protect against one-way connections. In topologies where fiber optic interconnections are used, physical misconnections can occur that allow a link to appear to be up when there is a mismatched set of transmit/receive pairs. When such a physical misconfiguration occurs, protocols such as STP
    SV-220640r539671_rule CISC-L2-000200 CCI-000366 MEDIUM The Cisco switch must have all trunk links enabled statically. When trunk negotiation is enabled via Dynamic Trunk Protocol (DTP), considerable time can be spent negotiating trunk settings (802.1q or ISL) when a node or interface is restored. While this negotiation is happening, traffic is dropped because the link is
    SV-220641r539671_rule CISC-L2-000210 CCI-000366 MEDIUM The Cisco switch must have all disabled switch ports assigned to an unused VLAN. A disabled port that is assigned to a user or management VLAN may become enabled by accident or by an attacker and as a result may gain access to that VLAN as a member.
    SV-220642r539671_rule CISC-L2-000220 CCI-000366 MEDIUM The Cisco switch must not have the default VLAN assigned to any host-facing switch ports. In a VLAN-based network, switches use the default VLAN (i.e., VLAN 1) for in-band management and to communicate with other networking devices using Spanning-Tree Protocol (STP), Dynamic Trunking Protocol (DTP), VLAN Trunking Protocol (VTP), and Port Aggre
    SV-220643r539671_rule CISC-L2-000230 CCI-000366 MEDIUM The Cisco switch must have the default VLAN pruned from all trunk ports that do not require it. The default VLAN (i.e., VLAN 1) is a special VLAN used for control plane traffic such as Spanning-Tree Protocol (STP), Dynamic Trunking Protocol (DTP), VLAN Trunking Protocol (VTP), and Port Aggregation Protocol (PAgP). VLAN 1 is enabled on all trunks and
    SV-220644r539671_rule CISC-L2-000240 CCI-000366 MEDIUM The Cisco switch must not use the default VLAN for management traffic. Switches use the default VLAN (i.e., VLAN 1) for in-band management and to communicate with directly connected switches using Spanning-Tree Protocol (STP), Dynamic Trunking Protocol (DTP), VLAN Trunking Protocol (VTP), and Port Aggregation Protocol (PAgP)
    SV-220645r539671_rule CISC-L2-000250 CCI-000366 MEDIUM The Cisco switch must have all user-facing or untrusted ports configured as access switch ports. Double encapsulation can be initiated by an attacker who has access to a switch port belonging to the native VLAN of the trunk port. Knowing the victim's MAC address and with the victim attached to a different switch belonging to the same trunk group, the
    SV-220646r539671_rule CISC-L2-000260 CCI-000366 MEDIUM The Cisco switch must have the native VLAN assigned to an ID other than the default VLAN for all 802.1q trunk links. VLAN hopping can be initiated by an attacker who has access to a switch port belonging to the same VLAN as the native VLAN of the trunk link connecting to another switch that the victim is connected to. If the attacker knows the victim’s MAC address, it
    SV-220647r539671_rule CISC-L2-000270 CCI-000366 LOW The Cisco switch must not have any switchports assigned to the native VLAN. Double encapsulation can be initiated by an attacker who has access to a switch port belonging to the native VLAN of the trunk port. Knowing the victim’s MAC address and with the victim attached to a different switch belonging to the same trunk group, t