On 2007-07-26 Johnny Wong wrote:
Over the past few months, we have faced situations where user PCs
were infected with virus when they connect to network mapped drives.
What happened was that the virus creates "autorun.inf" in the root of
the shared network drive, so users who double-click the drive in
Explorer, the autorun.inf executes the linked virus-infected
executable. Evem though the user PCs have anti-virus installed, the
incidents we faced so far, the virus was not detectable. It was
realised later that the virus was a new strain.
We have tried to disable the mapped-drives autorun feature (based on
registry key settings); however, it was not foolproof because the
autorun.inf was still able to execute in some cases. We found later
from Microsoft's KB (http://support.microsoft.com/kb/933008) that
this registry setting may not work. So we did not roll out this
registry settings to the users.
Anyone of you facing the same situation as me? I can only think of
the following solutions:
- keep AV signatures updated - this is not foolproof because most of
the time, the virus writers are leading the game. So we can only try
to send the first specimen we find ASAP to the AV vendors so that
they could develop signatures for them. Guessed by that time, a
number of users would have been infected.
- run a task on the file server that regularly checks for presence of
autorun.inf in the root of the shared folders, and if found, rename
or delete them. Implementation of this task will impact the
performance of the server when it hosts a lot of shared folders.
Please share your workarounds if you have any.
Disable autorun via group policy for all drives. Problem solved.
Autorun is evil(tm).
Regards
Ansgar Wiechers
--
"All vulnerabilities deserve a public fear period prior to patches
becoming available."
--Jason Coombs on Bugtraq
