Arch Linux: 201606-12 Medium: Lib32-GnuTLS Arbitrary File Overwrite

Arch Linux Security Advisory ASA-201606-12
=========================================
Severity: Medium
Date    : 2016-06-10
CVE-ID  : CVE-2016-4456
Package : lib32-gnutls
Type    : arbitrary file overwrite
Remote  : No
Link    : https://wiki.archlinux.org/title/CVE

Summary
======
The package lib32-gnutls before version 3.4.13-1 is vulnerable to
arbitrary file overwrite.

Resolution
=========
Upgrade to 3.4.13-1.

# pacman -Syu "lib32-gnutls>=3.4.13-1"

The problem has been fixed upstream in version 3.4.13.

Workaround
=========
None.

Description
==========
Setuid programs using GnuTLS could potentially allow an attacker to
overwrite and corrupt arbitrary files in the filesystem. This issue was
introduced in GnuTLS 3.4.12 with the GNUTLS_KEYLOGFILE environment
variable handling via getenv() and fixed in GnuTLS 3.4.13 by switching
to secure_getenv() where available.

Impact
=====
A local attacker is able to overwrite arbitrary files with a setuid
program using GnuTLS by setting the GNUTLS_KEYLOGFILE environment
variable.

References
=========
https://access.redhat.com/security/cve/CVE-2016-4456
http://gnutls.org/security.html#GNUTLS-SA-2016-1