Microsoft is rushing to fix a flaw introduced by the company's latest security update to Internet Explorer--a flaw that opens Windows users to attack, a security firm said on Tuesday.
The flaw, initially thought to only crash Internet Explorer, actually allows an attacker to run code on computers running Windows 2000 and Windows XP Service Pack 1 that have applied the August cumulative update to Internet Explorer 6 Service Pack 1, security firm eEye Digital Security asserted. The update, released on August 8, fixed eight security holes but also introduced a bug of its own, according to Marc Maiffret, chief hacking officer for the security firm, which notified Microsoft last week that the issue is exploitable.
By the following day, network administrators and users began complaining that the update, MS06-042 , caused Internet Explorer to crash when browsing some sites. Three days later, security researchers at eEye discovered that the issue could be used to not just crash the browser, but to compromise PCs running Windows XP SP1 and Windows 2000. Other security researchers have also reported the issue to Microsoft, Maiffret said.
"This information is definitely out in the underground," Maiffret said. "Because of all the discussions on security mailing lists, they know that this is a bug. Any half-decent researcher knows that this is an exploitable bug."
News source: Security Focus (full article)