Protect Your PCs from Windows 7's Zero-Day Exploit

A new zero-day bug has hit Windows 7. Here's how to keep it from harming your PCs
By Tony Bradley November 12, 2009

It was a notable accomplishment when Windows 7 was not impacted in any way by the vulnerabilities addressed in the six Security Bulletins released by Microsoft for the November Patch Tuesday. It would be even more impressive if Windows 7 proved invulnerable to the zero-day exploit that hit the next day. This newly found bug was discovered by Laurent Gaffie and details were posted on the Full Disclosure mailing list. Microsoft is investigating the reported flaw which basically crashes a Windows 7 system when exploited. The issue is in the SMB (Server Message Block) protocol that forms the backbone of Windows file sharing. When triggered, the flaw results in an infinite loop which renders the computer useless. Tyler Reguly, Lead Security Research Engineer with nCircle, explains "Exploitation of this vulnerability occurs when a user attempts to browse to Windows Share hosted on the malicious server. On Windows 7, the DoS (denial of service) will occur as soon as you type ‘\\\' in the search box. "

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