[Full-disclosure] AST-2012-002: Remote Crash Vulnerability in Milliwatt Application



Asterisk Project Security Advisory - AST-2012-002

Product Asterisk
Summary Remote Crash Vulnerability in Milliwatt Application
Nature of Advisory Exploitable Stack Buffer Overflow with locally
defined data
Susceptibility Remote Unauthenticated Sessions
Severity Minor
Exploits Known No
Reported On 03/14/2012
Reported By Russell Bryant
Posted On 03/15/2012
Last Updated On March 15, 2012
Advisory Contact Matt Jordan <mjordan AT digium DOT com>
CVE Name

Description An attacker can cause Asterisk to crash in one of two ways:

1. A dialplan uses the Milliwatt application with 'o'
option

2. The internal_timing opion in asterisk.conf is off

3. The attacker sends a large audio packet. The number of
samples in the audio packet determines the number of
internal data samples that are copied into the buffer. This
overruns the buffer, potentially causing a crash.

OR

1. A diaplan uses the Milliwatt application with the 'o'
option

2. The attacker negotiates a media format with a sampling
rate greater than 32kHz. The application will attempt to
generate an audio packet using the sample rate of the
negotiated format, where the sample rate will require a
number of data points greater then the size of the buffer.
Again, the the application copies a number of internal data
samples into the buffer that are greater then the size of
the buffer, potentially causing a crash.

Note that the latter attack vector is only possible in
Asterisk 10, as it supports codecs with a sample rate
greater then 32kHz.

Resolution Upgrade to one of the versions of Asterisk listed in the
"Corrected In" section, or apply a patch specified in the
"Patches" section.

Affected Versions
Product Release Series
Asterisk Open Source 1.4.x All Versions
Asterisk Open Source 1.6.2.x All Versions
Asterisk Open Source 1.8.x All Versions
Asterisk Open Source 10.x All Versions

Corrected In
Product Release
Asterisk Open Source 1.4.44
Asterisk Open Source 1.6.2.23
Asterisk Open Source 1.8.10.1
Asterisk Open Source 10.2.1

Patches
SVN URL Revision
http://downloads.asterisk.org/pub/security/AST-2012-002-1.4.diff v1.4
http://downloads.asterisk.org/pub/security/AST-2012-002-1.6.2.diff v1.6.2
http://downloads.asterisk.org/pub/security/AST-2012-002-1.8.diff v1.8
http://downloads.asterisk.org/pub/security/AST-2012-002-10.diff v10

Links https://issues.asterisk.org/jira/browse/ASTERISK-19541

Asterisk Project Security Advisories are posted at
http://www.asterisk.org/security

This document may be superseded by later versions; if so, the latest
version will be posted at http://downloads.digium.com/pub/security/.pdf
and http://downloads.digium.com/pub/security/.html

Revision History
Date Editor Revisions Made
03/15/2012 Matt Jordan Initial Release

Asterisk Project Security Advisory - AST-2012-002
Copyright (c) 2012 Digium, Inc. All Rights Reserved.
Permission is hereby granted to distribute and publish this advisory in its
original, unaltered form.

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