[arch-security] [ASA-201412-21] glibc: arbitrary code execution

[Levente Polyak]

Arch Linux Security Advisory ASA-201412-21
==========================================

Severity: High
Date    : 2014-12-18
CVE-ID  : CVE-2012-3406 CVE-2014-9402
Package : glibc lib32-glibc
Type    : arbitrary code execution, denial of service
Remote  : Yes
Link    : https://wiki.archlinux.org/index.php/CVE-2014

Summary
=======

The packages glibc and lib32-glibc before version 2.20-5 are vulnerable
to arbitrary code execution and denial of service.

Resolution
==========

Upgrade to 2.20-5.

# pacman -Syu "glibc>=2.20-5"
# pacman -Syu "lib32-glibc>=2.20-5"

The problems have been fixed upstream but no release is available yet.

Workaround
==========

None.

Description
===========

- CVE-2012-3406 (arbitrary code execution)
The vfprintf function in stdio-common/vfprintf.c in GNU C Library does
not "properly restrict the use of" the alloca function when allocating
the SPECS array, which allows context-dependent attackers to bypass the
FORTIFY_SOURCE format-string protection mechanism and cause a denial of
service (crash) or possibly execute arbitrary code via a crafted format
string using positional parameters and a large number of format specifiers.

- CVE-2014-9402 (denial of service)
The nss_dns getnetbyname function will enter an infinite loop if the DNS
backend is activated in the system Name Service Switch configuration and
the DNS resolver receives a positive answer while processing the network
name.

Impact
======

An attacker is able to perform a denial of service attack or execute
arbitrary code via crafted format strings.

References
==========

https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2012-3406
https://access.redhat.com/security/cve/CVE-2014-9402
https://sourceware.org/bugzilla/show_bug.cgi?id=17630
http://www.openwall.com/lists/oss-security/2014/12/18/1

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