Input validation error in asterisk (Alpine package)

1) Input validation error

EUVDB-ID: #VU50966

Risk: Medium

CVSSv4.0: 6.6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2021-26717

CWE-ID: CWE-20 - Improper input validation

Exploit availability: No

Description

The vulnerability allows a remote non-authenticated attacker to perform a denial of service (DoS) attack.

An issue was discovered in Sangoma Asterisk 16.x before 16.16.1, 17.x before 17.9.2, and 18.x before 18.2.1 and Certified Asterisk before 16.8-cert6. When re-negotiating for T.38, if the initial remote response was delayed just enough, Asterisk would send both audio and T.38 in the SDP. If this happened, and the remote responded with a declined T.38 stream, then Asterisk would crash.

Mitigation

Install update from vendor's website.

Vulnerable software versions

asterisk (Alpine package): 16.6.2-r0 - 16.14.1-r0

CPE2.3

• cpe:2.3:o:alpine:asterisk_alpine_package:16.6.2-r0:*:*:*:*:alpine_linux:*:3.11
• cpe:2.3:o:alpine:asterisk_alpine_package:16.7.0-r0:*:*:*:*:alpine_linux:*:3.11
• cpe:2.3:o:alpine:asterisk_alpine_package:16.14.1-r0:*:*:*:*:alpine_linux:*:3.11

External links

https://git.alpinelinux.org/aports/commit/?id=2a8bd0c3ec7d7286dd026c2535f523ce889ecda4
https://git.alpinelinux.org/aports/commit/?id=8b4dd3e383247c88e9ff182557e096d12a052634
https://git.alpinelinux.org/aports/commit/?id=9d426cf7a7701ee6707224d3e9f6d07553a56de1

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.