Check %ENV. There should be the name of the user and domain that they're authenticated in if it's using HTTP basic or digest authentication.

It's been so long since I've done it that I can't remember what the fields are named.

Apache sets the login username to the ENV variable REMOTE_USER. Using this I was able to do a LDAP search for the details.

Thanks everyone.

You might use Apache::Session to remember details about a session. Apache has no way to tell if some HTTP request comes from the same person that authenticated previously or from a new person. You need session-ids (for example stored in a cookie on the client browser) to connect the independent requests of a session with each other

LDAP authentication is handled simply by binding to the directory as the user you are attempting to authenticate. Other than the uesrname they entered there isn't any other information available about them. If you want to get information about them from the LDAP directory, the usual way to do that is to create a role account that the application can use to connect to the directory and query it for that information.