Microsoft Windows SMB NULL Session Authentication
Medium Nessus Plugin ID 26920
Synopsis
It is possible to log into the remote Windows host with a NULL session.
Description
The remote host is running Microsoft Windows. It is possible to log into it using a NULL session (i.e., with no login or password).
Depending on the configuration, it may be possible for an unauthenticated, remote attacker to leverage this issue to get information about the remote host.
Solution
Apply the following registry changes per the referenced Technet advisories :
Set :
- HKLM\SYSTEM\CurrentControlSet\Control\LSA\RestrictAnonymous=1
- HKLM\SYSTEM\CurrentControlSet\Services\lanmanserver\parameters\restrictnullsessaccess=1
Remove BROWSER from :
- HKLM\SYSTEM\CurrentControlSet\Services\lanmanserver\parameters\NullSessionPipes
Reboot once the registry changes are complete.