Title

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

Discussion

Application protocol anomaly detection examines application layer protocols such as SMTP 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 SMTP proxy must be included in the ALG. This ALG will be configured to inspect inbound and outbound SMTP and Extended SMTP communications traffic to detect protocol anomalies such as malformed message and command insertion attacks.

Check Content

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

Fix Text

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

Additional Identifiers

Rule ID: SV-68703r1_rule

Vulnerability ID: V-54457

Group Title: SRG-NET-000512-ALG-000064

Expert Comments

CCIs tied to check.

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