Asterisk Multiple Vulnerabilities (AST-2016-001 - AST-2016-003) (BEAST)
High Nessus Plugin ID 88715
Synopsis
A telephony application running on the remote host is affected by multiple vulnerabilities.
Description
According to its SIP banner, the version of Asterisk running on the remote host is affected by the following vulnerabilities :
- An information disclosure vulnerability, known as BEAST, exists in the SSL 3.0 and TLS 1.0 protocols due to a flaw in the way the initialization vector (IV) is selected when operating in cipher-block chaining (CBC) modes. A man-in-the-middle attacker can exploit this to obtain plaintext HTTP header data, by using a blockwise chosen-boundary attack (BCBA) on an HTTPS session, in conjunction with JavaScript code that uses the HTML5 WebSocket API, the Java URLConnection API, or the Silverlight WebClient API. (CVE-2011-3389)
- An integer overflow condition exists in sip.conf due to improper validation of user-supplied input when handling 'timert1' values. A remote attacker can exploit this to cause a denial of service.
- An unspecified flaw exists due to improper handling of FAT data in UDPTL packets. A remote attacker can exploit this to cause a denial of service.
Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.
Solution
Upgrade to Asterisk version 11.21.1 / 13.7.1 / 11.6-cert12 / 13.1-cert3. Alternatively, apply the appropriate patch referenced in the vendor advisories.