User not Identified by TSA or only Default CFS Policy Applied to User

03/26/2020 22 8753

DESCRIPTION:

No users are identified by the TSA (Terminal Service Agent) on a particular terminal server or the users are identified correctly but only the default CFS policy is applied.

CAUSE:

The web request of the user is proxied by a web filter service on the terminal server.

One example for this is the Sophos web filter included in the Sophos endpoint protection.

Because of the proxy the connection will be incorrectly identified as originating from the user that the proxy runs under (usually local system account) instead of the actual user that tries to view a web page.

To identify this issue do the following:

1. Enable verbose logging on the SonicWall Terminal Service Agent for the particular terminal server
2. Login a user on the terminal server
3. Try to browse to a website that no other user will currently use (ideally one with only a single IP, for example www.cork.ie which resolves to 89.185.146.136 at this time)
4. Open the Terminal Service Agent and view the logs
5. In the logs, search for the IP of the website that you tried to access
6. You should see which user was identified for this particular connection
7. If this user is not the user actually trying to access the website, chances are that the connection was proxied

RESOLUTION:

Disable the proxy functionality of your endpoint protection suite.