Microsoft's security team is investigating a security vulnerability in older versions of Windows that allows attackers to execute malware on end user machines.
The bug combines scripts based on Microsoft's Visual Basic language with Windows help files for Internet Explorer. It makes it possible for an attacker hosting a malicious website to remotely run arbitrary code by convincing the user to press the computer's F1 key in response to a popup window.
The vulnerability doesn't threaten users of Windows 7, Windows Server 2008, and Windows Vista, Microsoft's Jerry Bryant wrote here, and so far, there are no reports of attacks that exploit the weakness.
The attack was described on Friday by Maurycy Prodeus of iSec Security Research. The vulnerability is the result of the passing a samba share as a helpfile parameter, he said. The researcher also warned there is a stack based buffer overflow in the winhelp32.exe file when parameters are too long.
Microsoft plans to issue guidance once its investigation is completed, Bryant said. ®