Vulnerability identifier: #VU6620

Vulnerability risk: Medium

CVSSv3.1: 7.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: N/A

CWE-ID: CWE-125

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Asterisk Open Source
Server applications / Conferencing, Collaboration and VoIP solutions
Certified Asterisk
Server applications / Conferencing, Collaboration and VoIP solutions

Vendor: Digium (Linux Support Services)

Description
The vulnerability allows a remote attacker to cause DoS condition on the target system.

The weakness exists due to improper memory read. A remote attacker can send a specially crafted packet containing a long CSeq header value along with a Via header with no branch parameter, trigger an out-of-bounds memory read and cause the affected system to crash.

Successful exploitation of the vulnerability results in denial of service.

Mitigation
Update Asterisk to version 13.15.1 and 14.4.1.
Update Certified Asterisk to version 13.13-cert.

Vulnerable software versions

Asterisk Open Source: 13.0.1 - 13.15.0, 14.0 - 14.4.0

Certified Asterisk: 13.13

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External links
http://downloads.asterisk.org/pub/security/AST-2017-003.html

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.