Path traversal in FreeBSD

1) Path traversal

EUVDB-ID: #VU44516

Risk: High

CVSSv3.1: 7.9 [CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:P/RL:U/RC:C]

CVE-ID: CVE-2011-4122

CWE-ID: CWE-22 - Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

Exploit availability: Yes

Description

The vulnerability allows a remote attacker to perform directory traversal attacks.

The vulnerability exists due to input validation error when processing directory traversal sequences in openpam_configure.c in OpenPAM before r478 on FreeBSD 8.1. A remote authenticated attacker can send a specially crafted HTTP request and local users to load arbitrary DSOs and gain privileges via a . (dot dot) in the service_name argument to the pam_start function, as demonstrated by a . in the -c option to kcheckpass.

Mitigation

Cybersecurity Help is currently unaware of any official solution to address this vulnerability.

Vulnerable software versions

FreeBSD: 8.1

External links

http://c-skills.blogspot.com/2011/11/openpam-trickery.html
http://openwall.com/lists/oss-security/2011/12/07/3
http://openwall.com/lists/oss-security/2011/12/08/9
http://osvdb.org/76945
http://secunia.com/advisories/46756
http://secunia.com/advisories/46804
http://stealth.openwall.net/xSports/pamslam
http://trac.des.no/openpam/changeset/478/trunk/lib/openpam_configure.c
http://exchange.xforce.ibmcloud.com/vulnerabilities/71205

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. However, proof of concept for this vulnerability is available.