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: V1R3

Published: 2018-12-24

Updated At: 2019-01-27 11:43:22

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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-94117r1_rule SRG-NET-000235-FW-000160 CCI-001190 MEDIUM The firewall must fail closed if the firewall filtering function is nonfunctional. While failure to an open state may ensure users are not inconvenienced, it also circumvents a critical security network function that guards against direct and indirect network attacks. Allow traffic to flow without filtering or inspection puts the entire
    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-94121r1_rule SRG-NET-000202-FW-000039 CCI-001109 HIGH The firewall must be configured to use 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. 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-94123r1_rule SRG-NET-000132-FW-000026 CCI-000382 MEDIUM The firewall must be configured to prohibit or restrict the use of functions, ports, protocols, and/or services on the network segment in accordance as defined in the Ports, Protocols, and Services Management (PPSM) CAL and vulnerability assessments. Some ports, protocols, or services have well-known exploits or security weaknesses that can be leveraged in an attack against the enclave and put it at immediate risk. These ports, protocols, and services must be prohibited or restricted in the packet or
    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-94131r1_rule SRG-NET-000061-FW-000002 CCI-000067 MEDIUM The firewall that filters traffic from the wireless 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-94155r1_rule SRG-NET-000088-FW-000018 CCI-000139 MEDIUM The firewall must be configured to send a real-time alert to the ISSO and SA (at a minimum) in the event of an audit processing failure on the firewall itself. It is critical for the appropriate personnel to be aware if a system is at risk of failing to process traffic logs as required. Without this notification, the security personnel may be unaware of an impending failure of the audit capability and system ope
    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-94159r1_rule SRG-NET-000098-FW-000021 CCI-000162 MEDIUM The firewall must protect traffic log records from unauthorized access while in transit to the central audit server. Auditing and logging are key components of any security architecture. Logging the actions of specific events provides a means to investigate an attack, recognize resource utilization or capacity thresholds, or identify an improperly configured firewall. T
    SV-94161r1_rule SRG-NET-000098-FW-000022 CCI-000162 MEDIUM The firewall must protect traffic log records from unauthorized read access while stored locally. Auditing and logging are key components of any security architecture. Logging the actions of specific events provides a means to investigate an attack, recognize resource utilization or capacity thresholds, or identify an improperly configured firewall. T
    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-94169r1_rule SRG-NET-000235-FW-000133 CCI-001190 MEDIUM The firewall must fail to a secure state if the firewall filtering functions fail unexpectedly. Firewalls that fail suddenly and with no incorporated failure state planning may leave the hosting system available but with a reduced security protection. Failure to a known safe state helps prevent systems from failing to a state that may cause unauthor
    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-94173r1_rule SRG-NET-000362-FW-000159 CCI-002385 MEDIUM The perimeter firewall must be configured for service redundancy, load balancing, or other organization-defined safeguards to limit the effects of types of denial-of-service (DoS) attacks on the network. As a critical security system, perimeter firewalls must be safeguarded with redundancy measures. If the network does not provide safeguards against DoS attacks, network resources will be unavailable to users. Service redundancy techniques reduce the susce
    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-94179r2_rule SRG-NET-000364-FW-000033 CCI-002403 MEDIUM The firewall must establish ingress filters that block inbound packets where the destination is an IP address assigned to the management or loopback addresses of the enclave protection devices unless the packet has a source address assigned to the management network or network infrastructure. The firewall must reject requests for access or services where the source address received by the firewall specifies a loopback address. The network loopback address or management IP addresses should never be used as the source IP address of an inbound or
    SV-94181r1_rule SRG-NET-000364-FW-000034 CCI-002403 MEDIUM The firewall must block or restrict inbound IP packets destined to the control plane of the firewall itself. As a critical security system, perimeter firewalls must be safeguarded against direct attacks to the device. The firewall must have a filter that rejects requests for access or services where the source address received by the firewall specifies an extern
    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-94187r1_rule SRG-NET-000364-FW-000037 CCI-002403 MEDIUM The firewall must block outbound IP packets that contain illegitimate packet attributes including, at a minimum, invalid source address or packets that fail minimum length tests (TCP length, UDP length, IP data length) that have undefined protocol numbers, improper use of hop-by-hop header, or IPv6 RH0 header. If outbound communications traffic is not filtered, hostile activity intended to harm other networks may not be detected and prevented.
    SV-94189r1_rule SRG-NET-000365-FW-000038 CCI-001126 MEDIUM The firewall must be configured to fail securely in the event of an operational failure of the firewall filtering or boundary protection function. If a boundary protection device fails in an unsecure manner (open), information external to the boundary protection device may enter, or the device may permit unauthorized information release. Secure failure ensures that when a boundary control device fa
    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-94193r1_rule SRG-NET-000113-FW-000005 CCI-000169 LOW The firewall must be configured to allow the system administrator to select a subset of DoD-required auditable events. The generation of logs with a subset of criteria aide the system administrator, maintainers, and auditors when troubleshooting issues or reviewing the log for trends or security breaches. Traffic log records can be generated from various components with
    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