Yahoo patches critical Messenger bug
Yahoo! bug crushers have plugged a serious hole in Yahoo! Messenger that made it possible for bad guys to remotely take control of a user’s machine. The update became available less than 24 hours after an anonymous hacker posted proof-of-concept code that demonstrated how the vulnerability could be exploited. The vulnerability stems from a buffer overflow flaw in the messenger’s ActiveX control. Attackers could use it to remotely execute malicious code, or for other, less serious things, such forcing a user to log out of a chat or instant messaging session or crash Internet Explorer or another application. To carry out the attack, a miscreant must first prompt the victim to visit a booby-trapped website that contains specially crafted html code.
Ironically, Yahoo!’s own discussion of the flaw may have led to the exploit code, according to Marc Maiffret, a researcher at eEye Digital Security, the security firm that discovered the security hole. An advisory eEye posted on Wednesday warned only that “multiple flaws exist within Yahoo! Messenger which allow for remote execution of arbitrary code with minimal user interaction”, eEye refused to say more publicly, out of concern the additional details would enable someone to target the holes. While instant messaging quickly caught on as a favorite communication tool for the teenage set, it’s also become a key tool in the corporate world — speeding inter- and intra-office messages.
Source: eEye, Register
