Vulnerability identifier: #VU55294

Vulnerability risk: Medium

CVSSv3.1: 6.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-32558

CWE-ID: CWE-20

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 perform a denial of service (DoS) attack.

The vulnerability exists due to insufficient validation of user-supplied input within the IAX2 channel driver chan_iax2.c. A remote attacker can send a packet that contains an unsupported media format and perform a denial of service (DoS) attack.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Asterisk Open Source: 18.0.0 rc1 - 18.5.0 rc1, 17.0.0 - 17.9.3, 16.2.0 rc1 - 16.19.0 rc1, 13.23.0 rc1 - 13.38.2

Certified Asterisk: 16.3-cert1 - 16.8-cert9

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External links
http://downloads.asterisk.org/pub/security/AST-2021-008.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.