Authentication cache in Active Directory Jenkins Plugin allows logging in with any password

Jenkins Active Directory Plugin implements two separate modes: Integration with ADSI on Windows, and an OS agnostic LDAP-based mode. Optionally, to reduce lookup time, a cache can be configured to remember user lookups and user authentications.

In Active Directory Plugin prior to 2.20 and 2.16.1, when run in Windows/ADSI mode, the provided password was not used when looking up an applicable cache entry. This allows attackers to log in as any user using any password while a successful authentication of that user is still in the cache.

As a workaround for this issue, the cache can be disabled.

Active Directory Plugin 2.20 and 2.16.1 includes the provided password in cache entry lookup.

Additionally, the Java system property hudson.plugins.active_directory.CacheUtil.noCacheAuth can be set to true to no longer cache user authentications.