K09121542 : BIG-IP SSL/TLS vulnerability CVE-2021-22981

Security Advisory Description

The original TLS protocol includes a weakness in the master secret negotiation that is mitigated by the Extended Master Secret (EMS) extension defined in RFC 7627. TLS connections that do not use EMS are vulnerable to man-in-the-middle attacks during renegotiation. (CVE-2021-22981).

Impact

This vulnerability impacts the BIG-IP data plane. Attackers may set up a second Transport Layer Security (TLS) session with the same master secrets to carry out man-in-the-middle attacks (Triple Handshake attack) during TLS renegotiation.

For more information on BIG-IP support for RFC 7627: Transport Layer Security (TLS) Session Hash and Extended Master Secret Extension, refer to K66202244: Support for RFC 7627 extended master secret extension.