ASTERWEB Blog

Product Asterisk
Summary RTP/RTCP information leak
Nature of Advisory Unauthorized data disclosure
Susceptibility Remote Unauthenticated Sessions
Severity Critical
Exploits Known Yes
Reported On September 1, 2017
Reported By Klaus-Peter Junghanns
Posted On September 19, 2017
Last Updated On September 19, 2017
Advisory Contact Richard Mudgett
CVE Name CVE-2017-14099

Description This is a follow up advisory to AST-2017-005.

Insufficient RTCP packet validation could allow reading
stale buffer contents and when combined with the “nat” and
“symmetric_rtp” options allow redirecting where Asterisk
sends the next RTCP report.

The RTP stream qualification to learn the source address of
media always accepted the first RTP packet as the new
source and allowed what AST-2017-005 was mitigating. The
intent was to qualify a series of packets before accepting
the new source address.

Resolution The RTP/RTCP stack will now validate RTCP packets before
processing them. Packets failing validation are discarded.
RTP stream qualification now requires the intended series of
packets from the same address without seeing packets from a
different source address to accept a new source address.

Affected Versions
Product Release
Series
Asterisk Open Source 11.x All Releases
Asterisk Open Source 13.x All Releases
Asterisk Open Source 14.x All Releases
Certified Asterisk 11.6 All Releases
Certified Asterisk 13.13 All Releases

Corrected In
Product Release
Asterisk Open Source 11.25.3, 13.17.2, 14.6.2
Certified Asterisk 11.6-cert18, 13.13-cert6

Patches
SVN URL Revision
http://downloads.asterisk.org/pub/security/AST-2017-008-11.diff Asterisk
11
http://downloads.asterisk.org/pub/security/AST-2017-008-13.diff Asterisk
13
http://downloads.asterisk.org/pub/security/AST-2017-008-14.diff Asterisk
14
http://downloads.asterisk.org/pub/security/AST-2017-008-11.6.diff Certified
Asterisk
11.6
http://downloads.asterisk.org/pub/security/AST-2017-008-13.13.diff Certified
Asterisk
13.13

Links https://issues.asterisk.org/jira/browse/ASTERISK-27274

https://issues.asterisk.org/jira/browse/ASTERISK-27252

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This document may be superseded by later versions; if so, the latest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/AST-2017-008.pdf and
http://downloads.digium.com/pub/security/AST-2017-008.html

Product Asterisk
Summary Remote Crash Vulerability in res_pjsip
Nature of Advisory Denial of Service
Susceptibility Remote Unauthenticated Sessions
Severity Moderate
Exploits Known No
Reported On August 30, 2017
Reported By Ross Beer
Posted On
Last Updated On August 30, 2017
Advisory Contact George Joseph
CVE Name

Description A carefully crafted URI in a From, To or Contact header
could cause Asterisk to crash.

Resolution Patched pjsip_message_ip_updater to properly ignore the
trigger URI.

Affected Versions
Product Release Series
Asterisk Open Source 13.15.0
Asterisk Open Source 14.4.0

Corrected In
Product Release
Asterisk Open Source 13.17.1, 14.6.1

Patches
SVN URL Revision
http://downloads.asterisk.org/pub/security/AST-2017-007-13.diff Asterisk
13
http://downloads.asterisk.org/pub/security/AST-2017-007-14.diff Asterisk
14

Links https://issues.asterisk.org/jira/browse/ASTERISK-27152

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

Product Asterisk
Summary Shell access command injection in app_minivm
Nature of Advisory Unauthorized command execution
Susceptibility Remote Authenticated Sessions
Severity Moderate
Exploits Known No
Reported On July 1, 2017
Reported By Corey Farrell
Posted On
Last Updated On July 11, 2017
Advisory Contact Richard Mudgett
CVE Name

Description The app_minivm module has an “externnotify” program
configuration option that is executed by the MinivmNotify
dialplan application. The application uses the caller-id
name and number as part of a built string passed to the OS
shell for interpretation and execution. Since the caller-id
name and number can come from an untrusted source, a
crafted caller-id name or number allows an arbitrary shell
command injection.

Resolution Patched Asterisk’s app_minivm module to use a different
system call that passes argument strings in an array instead
of having the OS shell determine the application parameter
boundaries.

Affected Versions
Product Release
Series
Asterisk Open Source 11.x All releases
Asterisk Open Source 13.x All releases
Asterisk Open Source 14.x All releases
Certified Asterisk 11.6 All releases
Certified Asterisk 13.13 All releases

Corrected In
Product Release
Asterisk Open Source 11.25.2, 13.17.1, 14.6.1
Certified Asterisk 11.6-cert17, 13.13-cert5

Patches
SVN URL Revision
http://downloads.asterisk.org/pub/security/AST-2017-006-11.diff Asterisk
11
http://downloads.asterisk.org/pub/security/AST-2017-006-13.diff Asterisk
13
http://downloads.asterisk.org/pub/security/AST-2017-006-14.diff Asterisk
14
http://downloads.asterisk.org/pub/security/AST-2017-006-11.6.diff Certified
Asterisk
11.6
http://downloads.asterisk.org/pub/security/AST-2017-006-13.13.diff Certified
Asterisk
13.13

Links https://issues.asterisk.org/jira/browse/ASTERISK-27103

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/AST-2017-006.pdf and
http://downloads.digium.com/pub/security/AST-2017-006.html

Product Asterisk
Summary Media takeover in RTP stack
Nature of Advisory Unauthorized data disclosure
Susceptibility Remote Unauthenticated Sessions
Severity Critical
Exploits Known No
Reported On May 17, 2017
Reported By Klaus-Peter Junghanns
Posted On
Last Updated On August 30, 2017
Advisory Contact Joshua Colp
CVE Name

Description The "strictrtp" option in rtp.conf enables a feature of the
RTP stack that learns the source address of media for a
session and drops any packets that do not originate from
the expected address. This option is enabled by default in
Asterisk 11 and above.

The "nat" and "rtp_symmetric" options for chan_sip and
chan_pjsip respectively enable symmetric RTP support in the
RTP stack. This uses the source address of incoming media
as the target address of any sent media. This option is not
enabled by default but is commonly enabled to handle
devices behind NAT.

A change was made to the strict RTP support in the RTP
stack to better tolerate late media when a reinvite occurs.
When combined with the symmetric RTP support this
introduced an avenue where media could be hijacked. Instead
of only learning a new address when expected the new code
allowed a new source address to be learned at all times.

If a flood of RTP traffic was received the strict RTP
support would allow the new address to provide media and
with symmetric RTP enabled outgoing traffic would be sent
to this new address, allowing the media to be hijacked.
Provided the attacker continued to send traffic they would
continue to receive traffic as well.

Resolution The RTP stack will now only learn a new source address if it
has been told to expect the address to change. The RTCP
support has now also been updated to drop RTCP reports that
are not regarding the RTP session currently in progress. The
strict RTP learning progress has also been improved to guard
against a flood of RTP packets attempting to take over the
media stream.

Affected Versions
Product Release
Series
Asterisk Open Source 11.x 11.4.0
Asterisk Open Source 13.x All Releases
Asterisk Open Source 14.x All Releases
Certified Asterisk 11.6 All Releases
Certified Asterisk 13.13 All Releases

Corrected In
Product Release
Asterisk Open Source 11.25.2, 13.17.1, 14.6.1
Certified Asterisk 11.6-cert17, 13.13-cert5

Patches
SVN URL Revision
http://downloads.asterisk.org/pub/security/AST-2017-005-11.diff Asterisk
11
http://downloads.asterisk.org/pub/security/AST-2017-005-13.diff Asterisk
13
http://downloads.asterisk.org/pub/security/AST-2017-005-14.diff Asterisk
14
http://downloads.asterisk.org/pub/security/AST-2017-005-11.6.diff Certified
Asterisk
11.6
http://downloads.asterisk.org/pub/security/AST-2017-005-13.13.diff Certified
Asterisk
13.13

Links https://issues.asterisk.org/jira/browse/ASTERISK-27013

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/AST-2017-005.pdf and
http://downloads.digium.com/pub/security/AST-2017-005.html

Product Asterisk
Summary Memory exhaustion on short SCCP packets
Nature of Advisory Denial of Service
Susceptibility Remote Unauthenticated Sessions
Severity Critical
Exploits Known No
Reported On April 13, 2017
Reported By Sandro Gauci
Posted On
Last Updated On April 13, 2017
Advisory Contact George Joseph <gjoseph AT digium DOT com>
CVE Name

Description A remote memory exhaustion can be triggered by sending an
SCCP packet to Asterisk system with “chan_skinny†enabled
that is larger than the length of the SCCP header but
smaller than the packet length specified in the header. The
loop that reads the rest of the packet doesn’t detect that
the call to read() returned end-of-file before the expected
number of bytes and continues infinitely. The “partial
data†message logging in that tight loop causes Asterisk to
exhaust all available memory.

Resolution If support for the SCCP protocol is not required, remove or
disable the module.

If support for SCCP is required, an upgrade to Asterisk will
be necessary.

Affected Versions
Product Release Series
Asterisk Open Source 11.x Unaffected
Asterisk Open Source 13.x All versions
Asterisk Open Source 14.x All versions
Certified Asterisk 13.13 All versions

Corrected In
Product Release
Asterisk Open Source 13.15.1, 14.4.1
Certified Asterisk 13.13-cert4

Patches
SVN URL Revision

Links

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
13 April 2017 George Joseph Initial report created

Asterisk Project Security Advisory -
Copyright © 2017 Digium, Inc. All Rights Reserved.
Permission is hereby granted to distribute and publish this advisory in its
original, unaltered form.