The web server must restrict a consistent inbound source IP for the entire user session.

Authenticity protection provides protection against man-in-the-middle attacks/session hijacking and the insertion of false information into sessions.

Application communication sessions are protected utilizing transport encryption protocols, such as TLS. TLS provides web applications with a means to be able to authenticate user sessions and encrypt application traffic. Session authentication can be single (one way) or mutual (two way) in nature. Single authentication authenticates the server for the client, whereas mutual authentication provides a means for both the client and the server to authenticate each other.

This requirement addresses communications protection at the application session, versus the network packet, and establishes grounds for confidence at both ends of communications sessions in ongoing identities of other parties and in the validity of information transmitted. Depending on the required degree of confidentiality and integrity, web services will require the use of TLS mutual authentication (two-way/bidirectional).

Verify the web server limits authenticated user sessions to a consistent inbound IP for the entire user session

If the web server does not limit authenticated user sessions to a consistent inbound IP for the entire user session, this is a finding.

Configure the web server to restrict the user session to a consistent inbound IP for the entire user session.