Title

The Tomcat server must generate a unique session identifier for each session. (Cat II impact)

Discussion

Unique session IDs are the opposite of sequentially generated session IDs, which can be easily guessed by an attacker. Unique session identifiers help to reduce predictability of session identifiers. Unique session IDs address man-in-the-middle attacks, including session hijacking or insertion of false information into a session. If the attacker is unable to identify or guess the session information related to pending application traffic, they will have more difficulty in hijacking the session or otherwise manipulating valid sessions. Application servers must generate a unique session identifier for each application session so as to prevent session hijacking.

Check Content

Reveiew the Tomcat server.xml configuration: Determine if the randomClass attribute is not commented out and has a value. If the randomClass attribute is commented out or missing, this is a finding. Determine if the sessionIdLength attribute is 16 (default) or higher. If the sessionIdLength is commented out, missing, or not 16 or greater, this is a finding.

Fix Text

Configure the application server to generate a unique session identifier for each session.

Additional Identifiers

Rule ID: SV-71825r3_rule

Vulnerability ID: V-57549

Group Title:

Expert Comments

CCIs tied to check.

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