The security releases of Asterisk 11.25.2, 13.17.1, 14.6.1, 11.6-cert17, and 13.13-cert5 are now available, and are ready for immediate download at:
The release of these versions resolves the following security vulnerabilities:
AST-2017-005 (applied to all released versions): The “strictrtp” option in rtp.conf enables a feature of the RTP stack that learns the source address of media for a session and drops any packets that do not originate from the expected address. This option is enabled by default in Asterisk 11 and above. The “nat” and “rtp_symmetric” options for chan_sip and chan_pjsip respectively enable symmetric RTP support in the RTP stack. This uses the source address of incoming media as the target address of any sent media. This option is not enabled by default but is commonly enabled to handle devices behind NAT.
A change was made to the strict RTP support in the RTP stack to better tolerate late media when a reinvite occurs. When combined with the symmetric RTP support this introduced an avenue where media could be hijacked. Instead of only learning a new address when expected the new code allowed a new source address to be learned at all times.
If a flood of RTP traffic was received the strict RTPsupport would allow the new address to provide media and with symmetric RTP enabled outgoing traffic would be sent to this new address, allowing the media to be hijacked. Provided the attacker continued to send traffic they would continue to receive traffic as well.
- AST-2017-006 (applied to all released versions): The app_minivm module has an “externnotify” program configuration option that is executed by the MinivmNotify dialplan application. The application uses the caller-id name and number as part of a built string passed to the OS shell for interpretation and execution. Since the caller-id name and number can come from an untrusted source, a crafted caller-id name or number allows an arbitrary shell command injection.
- AST-2017-007 (applied only to 13.17.1 and 14.6.1): A carefully crafted URI in a From, To or Contact header could cause Asterisk to crash.
For a full list of changes in the current releases, please see the ChangeLogs:
The security advisories are available at:
Thank you for your continued support of Asterisk!