Asterisk Project Security Advisory – AST-2018-009

Asterisk Project Security Advisory – AST-2018-009

Product Asterisk
Summary Remote crash vulnerability in HTTP websocket upgrade
Nature of Advisory Denial Of Service
Susceptibility Remote Unauthenticated Sessions
Severity Moderate
Exploits Known No
Reported On August 16, 2018
Reported By Sean Bright
Posted On
Last Updated On September 20, 2018
Advisory Contact Rmudgett AT digium DOT com
CVE Name CVE-2018-17281

Description There is a stack overflow vulnerability in the module of Asterisk that allows an
attacker to crash Asterisk via a specially crafted HTTP
request to upgrade the connection to a websocket. The
attackeras request causes Asterisk to run out of stack
space and crash.

Resolution Disable HTTP websocket access by not loading the module or upgrade Asterisk to a fixed

Affected Versions
Product Release
Asterisk Open Source 13.x All releases
Asterisk Open Source 14.x All releases
Asterisk Open Source 15.x All releases
Certified Asterisk 13.21 All releases

Corrected In
Product Release
Asterisk Open Source 13.23.1, 14.7.8, 15.6.1
Certified Asterisk 13.21-cert3

SVN URL Revision Asterisk
13 Asterisk
14 Asterisk
15 Certified


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Revision History
Date Editor Revisions Made
August 31, 2018 Richard Mudgett Initial revision
September 20, 2018 Richard Mudgett Added CVE name.

Asterisk Project Security Advisory – AST-2018-009
Copyright A(c) 2018 Digium, Inc. All Rights Reserved.
Permission is hereby granted to distribute and publish this advisory in its
original, unaltered form.