Title

The ALG must invalidate session identifiers upon user logout or other session termination. (Cat II impact)

Discussion

Captured sessions can be reused in "replay" attacks. This requirement limits the ability of adversaries from capturing and continuing to employ previously valid session IDs. Session IDs are tokens generated by web applications to uniquely identify an application user's session. Unique session identifiers or IDs are the opposite of sequentially generated session IDs, which can be easily guessed by an attacker. Unique session IDs help to reduce predictability of said identifiers. When a user logs out, or when any other session termination event occurs, the network element must terminate the user session to minimize the potential for an attacker to hijack that particular user session. ALGs act as an intermediary for application; therefore, session control is part of the function provided. This requirement focuses on communications protection at the application session, versus network packet level.

Check Content

Verify the ALG invalidates session identifiers upon user logout or other session termination. If the ALG does not invalidate session identifiers upon user logout or other session termination, this is a finding.

Fix Text

Configure ALG to invalidate session identifiers upon user logout or other session termination.

Additional Identifiers

Rule ID: SV-68863r1_rule

Vulnerability ID: V-54617

Group Title: SRG-NET-000231-ALG-000114

Expert Comments

CCIs tied to check.

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