Reauthentication concepts

Security Verify Access WebSEAL can force a user to perform an additional login (reauthentication) to ensure that a user who is accessing a protected resource is the same person who initially authenticated at the start of the session. Forced reauthentication provides additional protection for sensitive resources in the secure domain.

Reauthentication can be activated by:

• A protected object policy (POP) on the protected object.
• Expiration of the inactivity timeout value of a WebSEAL session cache entry.

Reauthentication is supported by the following WebSEAL authentication methods:

• Forms (user name and password) authentication
• External authentication interface

In addition, a custom user name and password module can be written to support reauthentication. Reauthentication assumes the user has initially logged in to the secure domain and that a valid session (credential) exists for the user. The reauth-at-any-level option in the [reauthentication] stanza of the WebSEAL configuration file determines how WebSEAL handles a reauthentication operation:

• If the value for this option is no, the user must login using the same identity, authentication method, and authentication level that generated the existing credential. WebSEAL preserves the user's original session information, including the credential, during reauthentication. The credential is not replaced during reauthentication.

• If the value for this option is yes, the user must use the same identity but can be authenticated using a different authentication method or level from that which is currently held by the user. In this case, the user's credential can change one or more times during the lifetime of the user's session, and the user's credential is updated upon successful reauthentication. Note that this might have several consequences that must be carefully considered. If the credential changes during the course of an established session, then operations that utilize credential attributes, such as authorization decisions and auditing, might return different results mid-session. Care must be taken to ensure a consistent user experience and to account for these types of changes in audit records.

During reauthentication, WebSEAL also caches the request that prompted the reauthentication. Upon successful reauthentication, the cached data is used to rebuild the request. See Server-side request caching.

If reauthentication fails, WebSEAL returns the login prompt again. If reauthentication succeeds, but the ACL check fails for that resource, a 403 error ("Forbidden") is returned and the user is denied access to the requested resource.

In either case, the user is not logged off (the exception to this outcome is when the max-login-failures policy limit has been reached). Using a still valid credential, the user can terminate the reauthentication process (by requesting another URL) and still participate in the secure domain by accessing other resources that do not require reauthentication.

A configuration option exists that requires WebSEAL to remove the user's session cache entry and log the user out when the reauthentication attempts reach the max-login-failures policy limit.

Another configuration option is available to reset the lifetime timer of WebSEAL session cache entries. In addition, a grace period can be configured to allow sufficient time for the reauthentication process to complete before the lifetime timeout of a session cache entry expires.

Parent topic: Reauthentication