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← Back to Application Layer Gateway Security Requirements Guide

V-205048

CAT II (Medium)

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.

Rule ID

SV-205048r396519_rule

STIG

Application Layer Gateway Security Requirements Guide

Version

V2R3

CCIs

CCI-000366, CCI-001125

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.