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Windows SMB Subject to Denial-of-Service Attack

Microsoft is continuing to investigate holes in its Server Message Block (SMB) file-sharing protocol used in Windows.

Late Friday, Microsoft put out a yet another Security Advisory, saying it was looking into "new public reports of a denial-of-service vulnerability" in SMB.

The reported exploits touch SMBv1 and SMBv2 on Windows 7 and Windows Server 2008 R2 operating systems, according to the software giant.

Vista, Windows Server 2008, XP, Windows Server 2003 and Windows 2000 are not affected.

"Microsoft is aware of public, detailed exploit code that would cause a system to stop functioning or become unreliable," said Dave Forstrom, a spokesman for Microsoft Trustworthy Computing. "If exploited, this DoS vulnerability would not allow an attacker to take control of, or install malware on, the customer's system but could cause the affected system to stop responding until manually restarted."

Last Friday's advisory is the second such advisory since Redmond released one in September. This also marks the second time in as many months that news about vulnerabilities in the SMB program has emerged.

Forstrom said the default firewall settings on Windows 7 will help block attempts to exploit this latest DoS issue.

He added that while Microsoft is not currently aware of active attacks, customers should "review and implement the workarounds outlined in the advisory until a comprehensive security update is released."

About the Author

Jabulani Leffall is an award-winning journalist whose work has appeared in the Financial Times of London, Investor's Business Daily, The Economist and CFO Magazine, among others.

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