#VU44516 Path traversal in FreeBSD - CVE-2011-4122

Vulnerability identifier: #VU44516

Vulnerability risk: High

CVSSv4.0: 7.3 [CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P/U:Amber]

CVE-ID: CVE-2011-4122

CWE-ID: CWE-22

Exploitation vector: Local

Exploit availability: Yes

Vulnerable software:
FreeBSD
Operating systems & Components / Operating system

Vendor: FreeBSD Foundation

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

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

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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.