Three weaknesses in Tomcat's implementation of DIGEST
authentication were identified and resolved:
- Tomcat tracked client rather than server nonces and nonce count.
- When a session ID was present, authentication was bypassed.
- The user name and password were not checked before when indicating
that a nonce was stale.
These issues reduced the security of DIGEST authentication making
replay attacks possible in some circumstances.
The first issue was identified by Tilmann Kuhn. The second and third
issues were identified by the Tomcat security team during the code
review resulting from the first issue.