We'll have to wait and see if other 'fatal' combinations exist

Dec 21, 2011 08:21 GMT  ·  By

A hacker known as w3bd3vil posted a message on Twitter a couple of days ago claiming that he found a vulnerability in the 64-bit version of Windows 7 that could be taken advantage of using Apple’s popular web browser Safari.

“<iframe height='18082563'></iframe> causes a BSoD on win 7 x64 via Safari. Lol!” said the hacker in a tweet.

In a later tweet he provides further explanations, stating that the NtGdiDrawStream which is called multiple times is causing a “not so interesting crash.”

Researchers from Secunia confirm the accuracy of the hacker’s findings, reporting that the flaw can be utilized by a hacker to take over a machine.

“The vulnerability is caused due to an error in win32k.sys and can be exploited to corrupt memory via e.g. a specially crafted web page containing an IFRAME with an overly large 'height' attribute viewed using the Apple Safari browser. Successful exploitation may allow execution of arbitrary code with kernel-mode privileges,” reads Secunia’s report.

Unfortunately, the vulnerability is confirmed on a fully patched Windows 7 Professional 64-bit and other versions may also be affected by the security hole, which means that now the ball is in Microsoft’s court.

According to ThreatPost, Microsoft hasn’t confirmed the weakness, but the issue is being looked into.

“We are currently examining the issue and will take appropriate action to help ensure the customers are protected,” said Jerry Bryant, group manager of response communications in Microsoft's Trustworthy Computing Group.

So far, the attack method seems to work only on Safari, but it may later turn out that other web browsers can be utilized to launch a successful malicious operation.

The combination of Safari and Windows 7 is not very common, a potential attack being able to target only a limited number of users. Hopefully, in the meantime Microsoft will come forward with a quick fix to resolve the issue.