Override or set authenticated user in Apache 2.4 in conf

[Jan Cartman <knacktus@xxxxxxxxxxxxxx>]

Hi all,

 

I need to override the current authenticated user, e.g.

 

Joe Smith ABC fhjsdj342

to

fhjsdj342

As you can see, there's a fixed scheme (last token).

The new user id is needed for authorization.

I appreciate any hints or comments. But here are some more concrete questions:

1. Is the authenticated user stored in any way usable in the config? I know, for logging it can be received by %u. Then, there's the Apache variable REMOTE_USER, but as far as I understand this is intended to be used by CGI or SSI scripts and not for Rewrite or similiar?
2. If it is possible to modify the authenticated user, where would be the place to do so? Is it possible and reasonable to do it in a rewrite block?

Cheers,

Jan