Dear ladies and gentleman,

I have a question about the linux clamscan permissions.

By starting the clamscan from the linux desktop user - for example [user1] - it 
seems that clamscan gets the permissions as it was [user1], because it can 
remove infected files.

Therefore, if this was right, it would also have the privileges to write files.

By, for example, using third party virus signatures provided by Fangfrisch 
there could be the risk for a maliciously crafted signature file that is then 
downloaded by Fangfrisch or freshclam-service.

Because of the write/delete permissions clamscan seems to have, maliciously 
crafted code could be executed within the [user1] by clamscan.

Is there by any means a chance to give clamscan only read, but not write 
permissions, so that data could be crawled by clamscan but no arbitrary code 
executed could be written to the file system?

I acutally built a work around with a completely restricted user I have called 
[clamscan], who then is executed in the [user1] shell by su clamscan -s 
/bin/bash. Folders/files to be scanned are set to user1:clamscan by chown and 
0750 by chmod, so clamscan executed by
[clamscan] can only read but not write and [clamscan] itself has no write 
privileges in his own home folders. Works fine, but it's not just scanning some 
files by "hit and done".

When scanning external drives I have found a way, too, but it is very time 
consuming and only works with ext (FAT has no rights, NTFS can't be mounted by 
non-administrators and the users option in fstab doesn't seem to work with 
NTFS).

Therefore restricting clamav-clamscan's abilities would be the easiest solution.


Any help is appreciated very much.


Sincerely,

Michael
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