Permissions, Privileges, and Access Controls in FreeBSD

1) Permissions, Privileges, and Access Controls

EUVDB-ID: #VU42700

Risk: Medium

CVSSv3.1: 5.7 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2013-4851

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 vfs_hang_addrlist function in sys/kern/vfs_export.c in the NFS server implementation in the kernel in FreeBSD 8.3 and 9.x through 9.1-RELEASE-p5 controls authorization for host/subnet export entries on the basis of group information sent by the client, which allows remote attackers to bypass file permissions on NFS filesystems via crafted requests.

Mitigation

Install update from vendor's website.

Vulnerable software versions

FreeBSD: 8.3 - 9.1

External links

http://svnweb.freebsd.org/base?view=revision&revision=244226
http://www.freebsd.org/security/advisories/FreeBSD-SA-13:08.nfsserver.asc
http://www.securityfocus.com/bid/61484

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.