FreeBSD : FreeBSD -- Incorrect error handling in PAM policy parser (6e8f9003-6007-11e6-a6c3-14dae9d210b8)

Medium Nessus Plugin ID 92903


The remote FreeBSD host is missing one or more security-related updates.


The OpenPAM library searches for policy definitions in several locations. While doing so, the absence of a policy file is a soft failure (handled by searching in the next location) while the presence of an invalid file is a hard failure (handled by returning an error to the caller).

The policy parser returns the same error code (ENOENT) when a syntactically valid policy references a non-existent module as when the requested policy file does not exist. The search loop regards this as a soft failure and looks for the next similarly-named policy, without discarding the partially-loaded configuration.

A similar issue can arise if a policy contains an include directive that refers to a non-existent policy. Impact : If a module is removed, or the name of a module is misspelled in the policy file, the PAM library will proceed with a partially loaded configuration. Depending on the exact circumstances, this may result in a fail-open scenario where users are allowed to log in without a password, or with an incorrect password.

In particular, if a policy references a module installed by a package or port, and that package or port is being reinstalled or upgraded, there is a brief window of time during which the module is absent and policies that use it may fail open. This can be especially damaging to Internet-facing SSH servers, which are regularly subjected to brute-force scans.


Update the affected packages.

See Also

Plugin Details

Severity: Medium

ID: 92903

File Name: freebsd_pkg_6e8f9003600711e6a6c314dae9d210b8.nasl

Version: $Revision: 2.1 $

Type: local

Published: 2016/08/12

Modified: 2016/08/12

Dependencies: 12634

Risk Information

Risk Factor: Medium


Base Score: 5.1

Temporal Score: 4.4

Vector: CVSS2#AV:N/AC:H/Au:N/C:P/I:P/A:P

Temporal Vector: CVSS2#E:ND/RL:OF/RC:C

Vulnerability Information

CPE: p-cpe:/a:freebsd:freebsd:FreeBSD, cpe:/o:freebsd:freebsd

Required KB Items: Host/local_checks_enabled, Host/FreeBSD/release, Host/FreeBSD/pkg_info, Settings/ParanoidReport

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 2016/08/11

Vulnerability Publication Date: 2014/06/03

Reference Information

CVE: CVE-2014-3879

BID: 67808

FreeBSD: SA-14:13.pam