CVE-2023-49786 Information

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.

Reference

https://github.com/asterisk/asterisk/security/advisories/GHSA-hxj9-xwr8-w8pq https://github.com/asterisk/asterisk/commit/d7d7764cb07c8a1872804321302ef93bf62cba05 https://github.com/EnableSecurity/advisories/tree/master/ES2023-01-asterisk-dtls-hello-race