Permissions, Privileges, and Access Controls in FreeBSD

1) Permissions, Privileges, and Access Controls

EUVDB-ID: #VU42540

Risk: Medium

CVSSv3.1: 4.4 [CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:L/E:U/RL:O/RC:C]

CVE-ID: CVE-2013-5710

CWE-ID: CWE-264 - Permissions, Privileges, and Access Controls

Exploit availability: No

Description

The vulnerability allows a remote non-authenticated attacker to read and manipulate data.

The nullfs implementation in sys/fs/nullfs/null_vnops.c in the kernel in FreeBSD 8.3 through 9.2 allows local users with certain permissions to bypass access restrictions via a hardlink in a nullfs instance to a file in a different instance.

Mitigation

Install update from vendor's website.

Vulnerable software versions

FreeBSD: 8.0 - 9.2

External links

http://secunia.com/advisories/54861
http://svnweb.freebsd.org/base?view=revision&revision=255442
http://www.debian.org/security/2013/dsa-2769
http://www.freebsd.org/security/advisories/FreeBSD-SA-13:13.nullfs.asc
http://www.securitytracker.com/id/1029015

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

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