Security Basics: Re: Disabling autorun for mapped network drives

[Ansgar -59cobalt- Wiechers <bugtraq () planetcobalt net>]

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."
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