Yahoo Posts Exploit Fix for Messenger Flaws

By Lisa Vaas  |  Posted 2007-06-08 Print this article Print

The exploit code can take advantage of boundary errors in two ActiveX controls in Yahoo Messenger's Webcam Upload and Webcam Viewer to hijack customer systems.

Exploit code is out for critical Yahoo Messenger flaws found by eEye Digital Security earlier this week. (eEyes original security advisory is here.)

Both of the flaws, which allow for system hijacking, are boundary errors in two ActiveX controls in Yahoo Messengers Webcam Upload and Webcam Viewer.
Security researchers say that they expect attacks using the flaws to arrive soon. That makes prompt patching critical.
Yahoo has an update available, Version, to fix the vulnerability, posted at The company provided this statement on the issue: "The Yahoo Messenger team recently learned of a buffer overflow security issue in an ActiveX control. Upon learning of this issue, we began working towards a resolution and implemented a fix to Yahoo Messengers software download. We are encouraging all Yahoo Messenger users to download the latest version ( available at" Yahoo also plans to introduce a new version of its IM client over the "next several weeks" which users will be prompted to download upon signing into the service. The innocuous proof of concept code merely run Windows calculator, but the code poster—whose handle is "Danny"—says its "trivial" to change the shellcode. (Proof of concept code, or PoC, is often used as a synonym for a zero-day exploit that doesnt fully exploit a new vulnerability but provides code that shows how an exploit could be done). The exploit code is posted here on Neohapsis Archives. "Great results! very relible, runs calc.exe, replace with shellcode of your choice!!!" Danny wrote. Check out eWEEK.coms Security Center for the latest security news, reviews and analysis. And for insights on security coverage around the Web, take a look at eWEEKs Security Watch blog.
Lisa Vaas is News Editor/Operations for and also serves as editor of the Database topic center. Since 1995, she has also been a Webcast news show anchorperson and a reporter covering the IT industry. She has focused on customer relationship management technology, IT salaries and careers, effects of the H1-B visa on the technology workforce, wireless technology, security, and, most recently, databases and the technologies that touch upon them. Her articles have appeared in eWEEK's print edition, on, and in the startup IT magazine PC Connection. Prior to becoming a journalist, Vaas experienced an array of eye-opening careers, including driving a cab in Boston, photographing cranky babies in shopping malls, selling cameras, typography and computer training. She stopped a hair short of finishing an M.A. in English at the University of Massachusetts in Boston. She earned a B.S. in Communications from Emerson College. She runs two open-mic reading series in Boston and currently keeps bees in her home in Mashpee, Mass.

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