Firewall Security Requirements Guide

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]

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Version / Release: V1R5

Published: 2020-06-03

Updated At: 2020-08-15 20:22:16

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    Vuln Rule Version CCI Severity Title Description Status Finding Details Comments
    SV-94115r1_rule SRG-NET-000019-FW-000003 CCI-001414 HIGH The firewall must be configured to use filters that use packet headers and packet attributes, including source and destination IP addresses and ports, to prevent the flow of unauthorized or suspicious traffic between interconnected networks with different security policies (including perimeter firewalls and server VLANs). Information flow control regulates where information is allowed to travel within a network and between interconnected networks. Blocking or restricting detected harmful or suspicious communications between interconnected networks enforces approved authori
    SV-94119r1_rule SRG-NET-000362-FW-000028 CCI-002385 HIGH The firewall must employ filters that prevent or limit the effects of all types of commonly known denial-of-service (DoS) attacks, including flooding, packet sweeps, and unauthorized port scanning. Not configuring a key boundary security protection device such as the firewall against commonly known attacks is an immediate threat to the protected enclave because they are easily implemented by those with little skill. Directions for the attack are obt
    SV-94121r2_rule SRG-NET-000202-FW-000039 CCI-001109 HIGH The firewall must deny network communications traffic by default and allow network communications traffic by exception (i.e., deny all, permit by exception). To prevent malicious or accidental leakage of traffic, organizations must implement a deny-by-default security posture at the network perimeter. Such rulesets prevent many malicious exploits or accidental leakage by restricting the traffic to only known s
    SV-94125r1_rule SRG-NET-000192-FW-000029 CCI-001094 MEDIUM The firewall must block outbound traffic containing denial-of-service (DoS) attacks to protect against the use of internal information systems to launch any DoS attacks against other networks or endpoints. DoS attacks can take multiple forms but have the common objective of overloading or blocking a network or host to deny or seriously degrade performance. If the network does not provide safeguards against DoS attacks, network resources will be unavailable
    SV-94127r1_rule SRG-NET-000193-FW-000030 CCI-001095 MEDIUM The firewall implementation must manage excess bandwidth to limit the effects of packet flooding types of denial-of-service (DoS) attacks. A firewall experiencing a DoS attack will not be able to handle production traffic load. The high utilization and CPU caused by a DoS attack will also have an effect on control keep-alives and timers used for neighbor peering resulting in route flapping a
    SV-94129r1_rule SRG-NET-000061-FW-000001 CCI-000067 MEDIUM The firewall that filters traffic from the VPN access points must be configured with organization-defined filtering rules that apply to the monitoring of remote access traffic. Remote access devices (such as those providing remote access to network devices and information systems) that lack automated capabilities increase risk and make remote user access management difficult at best. Remote access is access to DoD non-public in
    SV-94133r1_rule SRG-NET-000019-FW-000004 CCI-001414 MEDIUM The firewall must immediately use updates made to policy enforcement mechanisms such as firewall rules, security policies, and security zones. Information flow policies regarding dynamic information flow control include, for example, allowing or disallowing information flows based on changes to the Ports, Protocols, Services Management [PPSM] Category Assurance Levels [CAL] list, vulnerability a
    SV-94135r1_rule SRG-NET-000492-FW-000006 CCI-000172 MEDIUM The firewall must generate traffic log records when traffic is denied, restricted, or discarded. Without generating log records that log usage of objects by subjects and other objects, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Security objects are data obj
    SV-94137r1_rule SRG-NET-000493-FW-000007 CCI-000172 MEDIUM The firewall must generate traffic log records when attempts are made to send packets between security zones that are not authorized to communicate. Without generating log records that are specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Access for di
    SV-94139r1_rule SRG-NET-000399-FW-000008 CCI-001462 MEDIUM The firewall must be configured to allow authorized users to record a packet capture based IP, traffic type (TCP, UDP, or ICMP), or protocol. Without the ability to capture, record, and log content related to a user session, investigations into suspicious user activity would be hampered. This configuration ensures the ability to select specific sessions to capture in order to support general a
    SV-94141r1_rule SRG-NET-000074-FW-000009 CCI-000130 MEDIUM The firewall must generate traffic log entries containing information to establish what type of events occurred. Without establishing what type of event occurred, it would be difficult to establish, correlate, and investigate the events leading up to an outage or attack. Audit event content that may be necessary to satisfy this requirement includes, for example, ti
    SV-94143r1_rule SRG-NET-000075-FW-000010 CCI-000131 MEDIUM The firewall must generate traffic log entries containing information to establish when (date and time) the events occurred. Without establishing when 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 of network traffic patterns,
    SV-94145r1_rule SRG-NET-000076-FW-000011 CCI-000132 MEDIUM The firewall must generate traffic log entries containing information to establish the location on the network where the events occurred. 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 securit
    SV-94147r1_rule SRG-NET-000077-FW-000012 CCI-000133 LOW The firewall must generate traffic log entries containing information to establish the source of the events, such as the source IP address at a minimum. 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
    SV-94149r1_rule SRG-NET-000078-FW-000013 CCI-000134 MEDIUM The firewall must generate traffic log entries containing information to establish the outcome of the events, such as, at a minimum, the success or failure of the application of the firewall rule. Without information about the outcome of events, security personnel cannot make an accurate assessment as to whether an attack was successful or if changes were made to the security state of the network. Event outcomes can include indicators of event suc
    SV-94151r1_rule SRG-NET-000333-FW-000014 CCI-001844 MEDIUM The firewall must be configured to send traffic log entries to a central audit server for management and configuration of the traffic log entries. Without the ability to centrally manage the content captured in the traffic log entries, identification, troubleshooting, and correlation of suspicious behavior would be difficult and could lead to a delayed or incomplete analysis of an ongoing attack. T
    SV-94153r1_rule SRG-NET-000335-FW-000017 CCI-001858 MEDIUM If communication with the central audit server is lost, the firewall must generate a real-time alert to, at a minimum, the SCA and ISSO. Without a real-time alert (less than a second), security personnel may be unaware of an impending failure of the audit functions and system operation may be adversely impacted. Alerts provide organizations with urgent messages. Automated alerts can be con
    SV-94157r1_rule SRG-NET-000089-FW-000019 CCI-000140 MEDIUM In the event that communication with the central audit server is lost, the firewall must continue to queue traffic log records locally. It is critical that when the network element is at risk of failing to process traffic logs as required, it takes action to mitigate the failure. Audit processing failures include software/hardware errors, failures in the audit capturing mechanisms, and au
    SV-94159r2_rule SRG-NET-000098-FW-000021 CCI-000162 MEDIUM The firewall must be configured to use TCP when sending log records to the central audit server. If the default UDP protocol is used for communication between the hosts and devices to the Central Log Server, then log records that do not reach the log server are not detected as a data loss. The use of TCP to transport log records to the log servers im
    SV-94163r1_rule SRG-NET-000099-FW-000161 CCI-000163 MEDIUM The firewall must protect the traffic log from unauthorized modification of local log records. If audit data were to become compromised, forensic analysis and discovery of the true source of potentially malicious system activity would be impossible to achieve. To ensure the veracity of audit data, the information system and/or the application must
    SV-94165r1_rule SRG-NET-000100-FW-000023 CCI-000164 MEDIUM The firewall must protect the traffic log from unauthorized deletion of local log files and log records. If audit data were to become compromised, forensic analysis and discovery of the true source of potentially malicious system activity would be impossible to achieve. To ensure the veracity of audit data, the information system and/or the application must
    SV-94167r1_rule SRG-NET-000131-FW-000025 CCI-000381 MEDIUM The firewall must disable or remove unnecessary network services and functions that are not used as part of its role in the architecture. Network devices are capable of providing a wide variety of functions (capabilities or processes) and services. Some of these functions and services are installed and enabled by default. The organization must determine which functions and services are requ
    SV-94169r2_rule SRG-NET-000235-FW-000133 CCI-001190 MEDIUM The firewall must fail to a secure state upon the failure of the following: system initialization, shutdown, or system abort. 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. Network elements that fail suddenly and with no incorporated failure state planning may leave the hosting s
    SV-94171r1_rule SRG-NET-000236-FW-000027 CCI-001665 MEDIUM In the event of a system failure of the firewall function, the firewall must be configured to save diagnostic information, log system messages, and load the most current security policies, rules, and signatures when restarted. Failure to a secure state can address safety or security in accordance with the mission needs of the organization. Failure to a secure state helps prevent a loss of confidentiality, integrity, or availability in the event of a failure of the information s
    SV-94175r1_rule SRG-NET-000364-FW-000031 CCI-002403 MEDIUM The firewall must apply ingress filters to traffic that is inbound to the network through any active external interface. Unrestricted traffic to the trusted networks 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. Firewall filt
    SV-94177r2_rule SRG-NET-000364-FW-000032 CCI-002403 MEDIUM The firewall must apply egress filters to traffic that is outbound from the network through any internal interface. If outbound communications traffic is not filtered, hostile activity intended to harm other networks or packets from networks destined to unauthorized networks may not be detected and prevented. Access control policies and access control lists implemente
    SV-94183r1_rule SRG-NET-000364-FW-000035 CCI-002403 MEDIUM The premise firewall (located behind the premise router) must block all outbound management traffic. The management network must still 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
    SV-94185r1_rule SRG-NET-000364-FW-000036 CCI-002403 MEDIUM The firewall must restrict traffic entering the VPN tunnels to the management network to only the authorized management packets based on destination address. Protect the management network with a filtering firewall configured to block unauthorized traffic. This requirement is similar to the out-of-band management (OOBM) model, when the production network is managed in-band. The management network could also be
    SV-94191r1_rule SRG-NET-000205-FW-000040 CCI-001097 MEDIUM The perimeter firewall must filter traffic destined to the internal enclave in accordance with the specific traffic that is approved and registered in the Ports, Protocols, and Services Management (PPSM) Category Assurance List (CAL), Vulnerability Assessments (VAs) for that the enclave. The enclave's internal network contains the servers where mission-critical data and applications reside. Malicious traffic can enter from an external boundary or originate from a compromised host internally. Vulnerability assessments must be reviewed by
    SV-94195r1_rule SRG-NET-000392-FW-000042 CCI-002664 LOW The firewall must generate an alert that can be forwarded to, at a minimum, the ISSO and ISSM when denial-of-service (DoS) incidents are detected. Without an alert, security personnel may be unaware of major detection incidents that require immediate action, and this delay may result in the loss or compromise of information. The firewall generates an alert that notifies designated personnel of the
    SV-110207r1_rule SRG-NET-000364-FW-000040 CCI-000366 MEDIUM The firewall must be configured to inspect all inbound and outbound traffic at the application layer. Application inspection enables the firewall to control traffic based on different parameters that exist within the packets such as enforcing application-specific message and field length. Inspection provides improved protection against application-based a
    SV-110209r1_rule SRG-NET-000364-FW-000041 CCI-000366 MEDIUM The firewall must be configured to inspect all inbound and outbound IPv6 traffic for unknown or out-of-order extension headers. IPv6 packets with unknown extension headers as well as out-of-order headers can create Denial-of-Service attacks for other networking components as well as host devices. IPv6 inspection can check conformance to RFC 2460 enforcing the order extension heade
    SV-110211r1_rule SRG-NET-000364-FW-000042 CCI-000366 MEDIUM The firewall must be configured to restrict it from accepting outbound packets that contain an illegitimate address in the source address field via an egress filter or by enabling Unicast Reverse Path Forwarding (uRPF). A compromised host in an enclave can be used by a malicious platform to launch cyberattacks on third parties. This is a common practice in "botnets", which are a collection of compromised computers using malware to attack other computers or networks. Deni