Title

The ALG that provides intermediary services for HTTP must inspect inbound and outbound HTTP traffic for protocol compliance and protocol anomalies. (Cat II impact)

Discussion

Application protocol anomaly detection examines application layer protocols such as HTTP to identify attacks based on observed deviations in the normal RFC behavior of a protocol or service. This type of monitoring allows for the detection of known and unknown exploits which exploit weaknesses of commonly used protocols. Since protocol anomaly analysis examines the application payload for patterns or anomalies, an HTTP proxy must be included in the ALG. This ALG will be configured to inspect inbound and outbound HTTP communications traffic to detect protocol anomalies such as malformed message and command insertion attacks. All inbound and outbound traffic, including HTTPS, must be inspected. However, the intention of this policy is not to mandate HTTPS inspection by the ALG. Typically, HTTPS traffic is inspected either at the source, destination and/or is directed for inspection by organizationally-defined network termination point.

Check Content

If the ALG does not provide intermediary/proxy services for HTTP communications traffic, this is not applicable. Verify the ALG inspects inbound and outbound HTTP communications traffic for protocol compliance and protocol anomalies. If the ALG does not inspect inbound and outbound HTTP communications traffic for protocol compliance and protocol anomalies, this is a finding.

Fix Text

If the ALG provides intermediary/proxy services for HTTP communications traffic, configure the ALG to inspect inbound and outbound HTTP communications traffic for protocol compliance and protocol anomalies.

Additional Identifiers

Rule ID: SV-68707r1_rule

Vulnerability ID: V-54461

Group Title: SRG-NET-000512-ALG-000066

Expert Comments

CCIs tied to check.

Controls tied to check. These are derived from the CCIs shown above.