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Submitted by: Bill Hickey
NCVA List Master
NRT-0327 Microsoft Scrambles to fix Windows XP Weaknesses:
Escalating attacks that use PDF files attached to emails to exploit a serious Windows XP weakness have prompted Microsoft to issue an urgent call to its developers to devise a fix. "We currently have teams worldwide who are working around the clock to develop an update of appropriate quality for broad distribution," Bill Sisk, a member of Microsoft's security response team wrote in a blog post Thursday. "Because ShellExecute is a core part of Windows, our development and testing teams are taking extra care to minimize application compatibility issues." In the meantime, users should take extra care when receiving email attachments, even when delivered from known sources, and when visiting familiar or unknown web sites, Sisk said.
Sisk's warning is being prompted by a flurry of spam-carrying rigged PDF files that exploit the vulnerability. Based on reports by independent researchers, the emails appear to be on the rise. According to Ken Dunham, director of global response for iSIGHT Partners, one source of his intercepted more than 75,000 hostile PDF attachments in the past few days, a rate that translates to one sample every 10 seconds.
"Multiple private sources are now reporting a high volume of emails containing hostile PDF attachments," Dunham wrote in an email. F-Secure is also reporting malware- tainted PDF files are "being spammed heavily through email."
For more than three months, Microsoft's security pros maintained that weaknesses resulting when third-party applications passed malicious uniform resource identifiers (URIs) to Internet Explorer were "not a vulnerability in a Microsoft product." As such, Redmond maintained, responsibility for plugging the hole lay elsewhere.
Two weeks ago, Microsoft apparently reversed itself on this position, saying for the first time that the URI-handling weakness was an issue that it had to address. This change in perspective came as it became increasingly clear that the URI-handling weakness was doomed to repeat itself over and over on countless third-party applications. As Sisk put it, "...these third party updates do not resolve the vulnerability - they just close an attack vector."
(The Register 26OCT07)
Last Modified: Saturday, 03-Nov-2007 10:21:30 EDT
