Firewall Security Requirements Guide

Overview

Version	Date	Finding Count (34)			Downloads
3	2024-12-04	CAT I (High): 3	CAT II (Medium): 29	CAT III (Low): 2	Excel JSON XML

Stig Description

This Security Requirements 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: disa.stig_spt@mail.mil.

Classified	Public	Sensitive
I - Mission Critical Classified	I - Mission Critical Public	I - Mission Critical Sensitive	II - Mission Critical Classified	II - Mission Critical Public	II - Mission Critical Sensitive	III - Mission Critical Classified	III - Mission Critical Public	III - Mission Critical Sensitive

Findings - All

Finding ID	Severity	Title	Description
V-206701	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 obtainable on the Internet and in hacker groups. Without filtering enabled...
V-206694	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 sources and only those ports, protocols, or services that are permitted and operationally necessary. As...
V-206674	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 authorizations for controlling the flow of traffic. The firewall that filters traffic outbound to interconnected networks with different security policies...
V-263649	Medium	The firewall must be configured to establish organization-defined alternate communications paths for system operations organizational command and control.	An incident, whether adversarial- or nonadversarial-based, can disrupt established communications paths used for system operations and organizational command and control. Alternate communications paths reduce the risk of all communications paths being affected by the same incident. To compound the problem, the inability of organizational officials to obtain timely information about...
V-263648	Medium	The firewall must be configured to implement physically or logically separate subnetworks to isolate organization-defined critical system components and functions.	Separating critical system components and functions from other noncritical system components and functions through separate subnetworks may be necessary to reduce susceptibility to a catastrophic or debilitating breach or compromise that results in system failure. For example, physically separating the command and control function from the in-flight entertainment function through...
V-263647	Medium	The firewall must be configured to employ organization-defined controls by type of denial-of-service (DoS) to achieve the DoS objective.	DoS events may occur due to a variety of internal and external causes, such as an attack by an adversary or a lack of planning to support organizational needs with respect to capacity and bandwidth. Such attacks can occur across a wide range of network protocols (e.g., IPv4, IPv6). A...
V-223013	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. DDoS attacks frequently leverage IP source address spoofing to...
V-223012	Medium	The firewall must be configured to inspect all inbound and outbound IPv6 traffic for unknown or out-of-order extension headers.
V-223011	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 attacks by restricting the types of commands allowed for the applications. Application inspection all enforces conformance against published RFCs....
V-206714	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 different security levels maintains separation between resources (particularly stored data) of...
V-206713	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 objects that are controlled by security policy and bound to security...
V-206708	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 housed at a Network Operations Center (NOC) that is located locally or remotely at...
V-206707	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 routed via the same links and nodes as that used...
V-206704	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 implemented on devices, such as firewalls, that control the flow of network traffic ensure the...
V-206703	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 filters control the flow of network traffic, ensure the flow of traffic is only...
V-206700	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 conveyed in a variety of ways, including via a regularly monitored console,...
V-206699	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. The DoD requires centralized management of all network component audit record content. Network...
V-206698	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 system or a component of the system. Preserving...
V-206696	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 system available but with a reduced security protection...
V-206695	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 the SA and protocols must be approved by the IA staff before entering the enclave. Firewall...
V-206693	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 and will eventually black hole production traffic....
V-206692	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 to users. Installation of a firewall at key boundaries in...
V-206690	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 required to perform the content filtering and other necessary core functionality for each...
V-206688	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 protect audit information from unauthorized modification. This can be achieved through...
V-206687	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 protect audit information from unauthorized modification. This can be achieved through...
V-206685	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 improves delivery...
V-206682	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 success or failure and event-specific results. They also provide a...
V-206680	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 security personnel to know where events occurred, such as network element components,...
V-206679	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, it is essential for security personnel to know when flow control events...
V-206678	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, time stamps, source and destination addresses, user/process identifiers, event descriptions, success/fail...
V-206676	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 information systems by an authorized user (or an information system) communicating through an...
V-206675	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 assessments, or mission conditions. Changing conditions include changes in the threat environment and detection of potentially harmful or...
V-206711	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 Indicators of Compromise (IOCs), which require real-time alerts. These messages should...
V-206681	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 know the source of the event. In addition to logging...