Asterisk 13.10.x < 13.11.1 ACK Handling Unrecognized Username NULL Pointer Dereference DoS (AST-2016-006)

Medium Nessus Plugin ID 93533


A telephony application running on the remote host is affected by a denial of service vulnerability.


According to its SIP banner, the version of Asterisk running on the remote host is 13.10.x prior to 13.11.1. It is, therefore, affected by a NULL pointer dereference flaw due to improper handling of ACK packets from an unknown username. An unauthenticated, remote attacker can exploit this to crash the program, resulting in a denial of service. This vulnerability only affects installations using the PJSIP stack; installations using chan_sip are unaffected.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.


Upgrade to Asterisk version 13.11.1.

See Also

Plugin Details

Severity: Medium

ID: 93533

File Name: asterisk_ast_2016_006.nasl

Version: $Revision: 1.6 $

Type: remote

Family: Misc.

Published: 2016/09/15

Modified: 2017/02/16

Dependencies: 63202

Risk Information

Risk Factor: Medium


Base Score: 5

Temporal Score: 4.1

Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:P

Temporal Vector: CVSS2#E:F/RL:OF/RC:ND


Base Score: 7.5

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Vulnerability Information

CPE: cpe:/a:digium:asterisk

Required KB Items: asterisk/sip_detected, Settings/ParanoidReport

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 2016/09/08

Vulnerability Publication Date: 2016/09/08

Reference Information

BID: 92886

OSVDB: 144029