An issue was discovered in Asterisk 13.18.4 and older, 14.7.4 and older, 15.1.4 and older, and 13.18-cert1 and older. A select set of SIP messages create a dialog in Asterisk. Those SIP messages must contain a contact header. For those messages, if the header was not present and the PJSIP channel driver was used, Asterisk would crash. The severity of this vulnerability is somewhat mitigated if authentication is enabled. If authentication is enabled, a user would have to first be authorized before reaching the crash point.

The remote host is affected by the vulnerability described in GLSA-201811-11 (Asterisk: Multiple vulnerabilities)

    Multiple vulnerabilities have been discovered in Asterisk. Please review       the referenced CVE identifiers for details.
  Impact :

    A remote attacker could cause a Denial of Service condition or conduct       information gathering.
  Workaround :

    There is no known workaround at this time.

Update to upstream 14.7.5 release for AST-2017-014/CVE-2017-17850 security issue

Note that Tenable Network Security has extracted the preceding description block directly from the Fedora update system website.
Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

According to its SIP banner, the version of Asterisk running on the remote host is 13.x prior to 13.18.5, 14.x prior to 14.7.5, 15.x prior to 15.1.5, or 13.18 prior to 13.18-cert2. It is therefore, affected by a remote denial of service attack as described in AST-2017-014.

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

The Asterisk project reports :

A select set of SIP messages create a dialog in Asterisk. Those SIP messages must contain a contact header. For those messages, if the header was not present and using the PJSIP channel driver, it would cause Asterisk to crash. The severity of this vulnerability is somewhat mitigated if authentication is enabled. If authentication is enabled a user would have to first be authorized before reaching the crash point.

ID	Name	Product	Family	Severity
119131	GLSA-201811-11 : Asterisk: Multiple vulnerabilities	Nessus	Gentoo Local Security Checks	high
105861	Fedora 27 : asterisk (2017-41242dfe10)	Nessus	Fedora Local Security Checks	high
105545	Asterisk 13.x < 13.18.5 / 14.x < 14.7.5 / 15.x < 15.1.5 / 13.13 < 13.18-cert2 Crash in PJSIP (AST-2017-014)	Nessus	Misc.	high
105448	FreeBSD : asterisk -- Crash in PJSIP resource when missing a contact header (2a3bc6ac-e7c6-11e7-a90b-001999f8d30b)	Nessus	FreeBSD Local Security Checks	high

Detections

Analytics

CVE-2017-17850

high

Tenable Plugins

high

high

high

high