SYNTHESIS OF THE VULNERABILITY

When the mount.cifs tool is installed suid root, a local attacker can use a symbolic link, in order to elevate his privileges or to obtain information.

Severity: 2/4

Consequences: administrator access/rights, privileged access/rights, user access/rights, data reading

Provenance: user shell

Means of attack: 1 attack

Ability of attacker: technician (2/4)

Confidence: confirmed by the editor (5/5)

Diffusion of the vulnerable configuration: high (3/3)

Creation date: 29/01/2010

IMPACTED PRODUCTS

 Samba

DESCRIPTION OF THE VULNERABILITY

The mount.cifs utility of the Samba suite is used to mount a remote CIFS/SMB share in a local directory. This tool is frequently installed suid root.

However, this tool does not atomically check the mount directory. A local attacker can therefore:

 call mount.cifs to mount a remote share on /home/user/mydir
 during its execution, replace /home/user/mydir by a symbolic link to /privatedirectory
 wait for mount.cifs to mount the share on /privatedirectory

So, by modifying/reading the content of the share on the remote server, the local attacker can modify/read to content of /privatedirectory.

When the mount.cifs tool is installed suid root, a local attacker can therefore use a symbolic link, in order to elevate his privileges or to obtain information.

CHARACTERISTICS

Identifiers: 532940, 6853, BID-37992, CVE-2009-3297, VIGILANCE-VUL-9390

http://vigilance.fr/vulnerability/S...