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Two new WMF bugs found

Two new WMF bugs found

Two more WMF vulnerabilities have been found in the Windows operating system.

Just days after Microsoft patched a critical vulnerability in the way the Windows operating system renders certain types of graphics files, a hacker has published details of two new flaws that affect the same part of the operating system.

The new vulnerabilities were posted to the Bugtraq security mailing list by a hacker going by the name of cocoruder. (http://msgs.securepoint.com/cgi-bin/get/bugtraq0601/90.html)

All three flaws concern the way Windows renders images in the Windows Metafile (WMF) format used by some CAD (computer-aided design) applications, but these latest flaws are far less serious than the vulnerability that Microsoft patched last week, according to security experts. That vulnerability was serious enough to cause Microsoft to take the unusual step of releasing an early patch to the problem, ahead of its monthly security software update.

While the patched flaw was being exploited by attackers to take control of Windows machines, the latest vulnerabilities appear to pose the risk of simply crashing the WMF-viewing software, typically Internet Explorer. However, users would first need to trick a victim into viewing a specially crafted WMF image in order for this to happen, security experts say.

The vulnerabilities can be found in a number of versions of Windows, including Windows XP, Service Pack 2, Windows Server 2003, Service Pack 1, and Windows 2000, Service Pack 4, according to cocoruder's Bugtraq posting.

Because of the inherent complexity of image formats, there were plenty of opportunities for attackers to find bugs similar to the two that were revealed, senior information security analyst for Cybertrust, Russ Cooper, said.

Cooper said that the new WMF vulnerabilities were not a major cause of concern.

"New malformed images that simply crash things aren't really that important unless they can be shown to cause code to execute," he said. "This is only getting any attention because its WMF and Microsoft just released a WMF patch."

Johannes Ullrich, chief research officer for the SANS Institute, agreed that these type of image problems were fairly common, but he said that the fact that so many WMF vulnerabilities had popped up recently - Microsoft fixed three other WMF bugs in November - indicated that the software vendor could be doing a better job of predicting where its security problems might lie.

Microsoft should have been able to catch these latest flaws and fix them with its November patch, Ullrich said.

"They really seem to have a problem thinking offensively," he said. "If you don't really look for these vulnerabilities with this offensive mindset, but if you instead look at it from a programmers perspective ... you just don't find a lot of these things."

"Every month they have one or two image problems they fix," Ullrich said. "It's actually kind of surprising they don't get exploited more."

A spokesperson from Microsoft was unable to provide comment for this story.


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