Race condition in shadow

1) Time-of-check Time-of-use (TOCTOU) Race Condition

EUVDB-ID: #VU59131

Risk: Low

CVSSv3.1: 4.1 [CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2013-4235

CWE-ID: CWE-367 - Time-of-check Time-of-use (TOCTOU) Race Condition

Exploit availability: No

Description

The vulnerability allows a local user to delete or modify arbitrary files on the system.

The vulnerability exists due to a race condition in shadow-utils when executing usermod/userdel operations. A local user with write access to the directory that is being moved or deleted by the usermod/userdel commands can modify or delete arbitrary files on the system.

Successful exploitation of the vulnerability may allow an attacker to corrupt arbitrary files on the system and perform a denial of service (DoS) attack.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

shadow: 4.0.0 - 20001016

External links

http://access.redhat.com/security/cve/cve-2013-4235
http://bugzilla.redhat.com/show_bug.cgi?id=CVE-2013-4235
http://lists.apache.org/thread.html/rf9fa47ab66495c78bb4120b0754dd9531ca2ff0430f6685ac9b07772@%3Cdev.mina.apache.org%3E
http://security-tracker.debian.org/tracker/CVE-2013-4235

Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.