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SYNTHESIS OF THE VULNERABILITY

When the ncpmount and ncpumount tools are installed suid root, a local attacker can use a symbolic link, in order to elevate his privileges, to obtain information or to create a denial of service.

Severity: 2/4

Consequences: administrator access/rights, privileged access/rights, user access/rights, data reading, denial of service of service, denial of service of client

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

 Unix - plateform

DESCRIPTION OF THE VULNERABILITY

The ncpmount and ncpumount utilities are used to mount a remote NCP (NetWare Core Protocol) share in a local directory. These tools are frequently installed suid root.

However, the ncpmount tool does not atomically check the mount directory. A local attacker can therefore:
 call ncpmount to mount a remote share on /home/user/mydir
 during its execution, replace /home/user/mydir by a symbolic link to /privatedirectory
 wait for ncpmount 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.

Moreover, the ncpumount tool does not atomically check the directory to be unmounted. A local attacker can therefore:
 call "ncpumount /home/user/mydir"
 during its execution, replace /home/user/mydir by a symbolic link to /privatedirectory
 wait for ncpumount to unmount /privatedirectory

A local attacker can thus unmount a mount point belonging to another user.

When the ncpmount and ncpumount tools are installed suid root, a local attacker can therefore use a symbolic link, in order to elevate his privileges, to obtain information or to create a denial of service.

CHARACTERISTICS

Identifiers: 532940, CVE-2009-3297, VIGILANCE-VUL-9392

http://vigilance.fr/vulnerability/n...