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05 Jan 2006

Microsoft releases critical WMF vulnerability fix early

Sophos warns that hackers are actively exploiting security hole

Microsoft has described the vulnerability as critical
Microsoft has described the WMF vulnerability as critical.

Experts at SophosLabs™, Sophos's global network of virus, spyware and spam analysis centers, have advised computer users to apply a critical Microsoft security patch which protects against a vulnerability in the way Windows handles WMF graphic files. Sophos has seen over 200 different attempts to infect innocent computer users using the flaw which has been public knowledge since late December 2005.

Unusually, Microsoft has issued the critical security update outside of its normal monthly update cycle. Originally Microsoft had indicated that it would not be issuing the patch until Tuesday 10 January, causing some in the security community to express concern that hackers would have a significant opportunity to infect internet users.

"It's good news that Microsoft has been able to issue this patch sooner rather than later. This flaw in Microsoft's software is very dangerous, and is being actively exploited by hackers to distribute malware. It's critical that businesses and home users protect against flaws like this as a matter of priority," said Graham Cluley, senior technology consultant for Sophos. "Our advice to companies and home users to waste no time in implementing this patch."

Home users of Microsoft Windows can visit to have their systems scanned for critical Microsoft security vulnerabilities.

Experts at Sophos are reminding users that hackers are continuing to actively exploit the security hole, even though a fix is now available.

In the latest sighted attacks emails with the subject line "Happy New Year 2" have been spammed out, pointing users to a website pretending to be an online e-card from However, the link really points to a malicious website based in the Netherlands.

"Hackers are in a race against time to infect as many computers as possible through the WMF security hole before companies have a chance to put the patch in place," explained Cluley. "Everyone should apply the patch as soon as possible, and defend their networks with up-to-date anti-virus and anti-spam software."

Happy New Year emails are being sent that pretend to point to an online greeting, but really send users to a malicious website

Happy New Year emails are being sent that pretend to point to an online greeting, but really send users to a malicious website.

Sophos suggests that every IT manager responsible for security should consider subscribing to vulnerability mailing lists such as that operated by Microsoft at

Sophos continues to recommend companies protect their desktops and servers with automatically updated anti-virus protection.

About Sophos

More than 100 million users in 150 countries rely on Sophos as the best protection against complex threats and data loss. Sophos is committed to providing complete security solutions that are simple to deploy, manage, and use and that deliver the industry's lowest total cost of ownership. Sophos offers award-winning encryption, endpoint security, web, email, mobile and network security solutions backed by SophosLabs - a global network of threat intelligence centers.

Sophos is headquartered in Boston, US and Oxford, UK. More information is available at