Software Engineering Institute

Yahoo! Messenger is an instant messaging application that is available for Windows, Mac, Unix, web, and mobile systems. Some version of Yahoo! Messenger, such as the Windows and Mac versions, support webcam use. When Yahoo! Messenger views a webcam stream, it makes a connection to port 5100/tcp. The webcam video stream is sent as a JPEG 2000 code stream. Yahoo! Messenger appears to require user interaction to connect a webcam stream.

Yahoo! Messenger contains a heap overflow in the handling of a malformed JPEG 2000 code streams. Exploit code that causes a denial of service is publicly available.

A remote attacker may be able to execute arbitrary code with the privileges of the user running Yahoo! Messenger. This vulnerability may also cause a denial of service by causing Yahoo! Messenger to crash.

Apply an update
This issue is addressed by the Yahoo! Webcam Security Update. Versions of Yahoo! Messenger downloaded after August 21, 2007 contain kdv_v32M.dll version 3.2.0.2 and ywcvwr.dll version 2.0.1.9, which address the vulnerability.

Restrict network access

This vulnerability can be mitigated by blocking outgoing connections to 5100/tcp. This appears to prevent Yahoo! Messenger from connecting to a webcam stream.

Do not accept webcam invitations

Until this vulnerability has been addressed by the vendor, do not accept any Yahoo! Messenger webcam invitations, regardless of the source.