Vulnerability · Published Dec 14, 2023 · Assigned by GitHub_M
CVE-2023-49786Asterisk susceptible to Denial of Service via DTLS Hello packets during call initiation
High 7.5
In plain English
A high-severity security flaw in asterisk from asterisk. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 5.3% (higher than 93% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
Asterisk is an open source private branch exchange and telephony toolkit. In Asterisk prior to versions 18.20.1, 20.5.1, and 21.0.1; as well as certified-asterisk prior to 18.9-cert6; Asterisk is susceptible to a DoS due to a race condition in the hello handshake phase of the DTLS protocol when handling DTLS-SRTP for media setup. This attack can be done continuously, thus denying new DTLS-SRTP encrypted calls during the attack. Abuse of this vulnerability may lead to a massive Denial of Service on vulnerable Asterisk servers for calls that rely on DTLS-SRTP. Commit d7d7764cb07c8a1872804321302ef93bf62cba05 contains a fix, which is part of versions 18.20.1, 20.5.1, 21.0.1, amd 18.9-cert6.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.20 | asterisk | 20.5.1-r0 | ALPINE-CVE-2023-49786 |
| Alpine:v3.21 | asterisk | 20.5.1-r0 | ALPINE-CVE-2023-49786 |
| Alpine:v3.22 | asterisk | 20.5.1-r0 | ALPINE-CVE-2023-49786 |
| Alpine:v3.23 | asterisk | 20.5.1-r0 | ALPINE-CVE-2023-49786 |
| Alpine:v3.24 | asterisk | 20.5.1-r0 | ALPINE-CVE-2023-49786 |
| Debian:14 | asterisk | 1:20.5.1~dfsg+~cs6.13.40431414-1 | DEBIAN-CVE-2023-49786 |
| Ubuntu:22.04:LTS | asterisk | no fix listed | UBUNTU-CVE-2023-49786 |
| Ubuntu:24.04:LTS | asterisk | no fix listed | UBUNTU-CVE-2023-49786 |
| Ubuntu:25.10 | asterisk | no fix listed | UBUNTU-CVE-2023-49786 |
| Ubuntu:26.04:LTS | asterisk | no fix listed | UBUNTU-CVE-2023-49786 |
| Ubuntu:26.10 | asterisk | no fix listed | UBUNTU-CVE-2023-49786 |
Affected products (as reported)
Weakness: CWE-703 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
References
- https://github.com/asterisk/asterisk/security/advisories/GHSA-hxj9-xwr8-w8pq x_refsource_CONFIRM
- https://github.com/asterisk/asterisk/commit/d7d7764cb07c8a1872804321302ef93bf62cba05 x_refsource_MISC
- https://github.com/EnableSecurity/advisories/tree/master/ES2023-01-asterisk-dtls-hello-race x_refsource_MISC
- http://www.openwall.com/lists/oss-security/2023/12/15/7
- http://packetstormsecurity.com/files/176251/Asterisk-20.1.0-Denial-Of-Service.html
- http://seclists.org/fulldisclosure/2023/Dec/24
- https://lists.debian.org/debian-lts-announce/2023/12/msg00019.html