Microsoft handed IT administrators a surprise late Thursday -- the much-anticipated patch for a Windows Meta File (WMF) glitch that has already been the target of numerous exploits. The company released the fix at 4 p.m. ET in security bulletin MS06-001.
The Redmond, Wash.-based software giant made the announcement on its TechNet site, in a message otherwise intended as a heads-up on what to expect this coming Patch Tuesday.
The software giant stressed that its monitoring of attack data "continues to indicate that the attacks are limited and are being mitigated both by Microsoft's efforts to shut down malicious Web sites and with up-to-date signatures from antivirus companies."
The patch being released Thursday fixes a design flaw in how Windows handles its image files.
Originally designed to assist when a print job needed to be canceled during spooling, the function has been rigged by malicious coders to compromise machines running Windows XP (including those with the SP 2 patch installed), ME, 2000 and Windows Server 2003 by hiding malicious code on a Web page or e-mail containing .WMF files. Vendors reported last week that the flaw is primarily being used to sneak spyware onto computers.
As for Patch Tuesday, Microsoft said customers can expect two security bulletins for critical vulnerabilities in Windows, Exchange and Office. Users will have to wait until then to learn what the specific flaws are. And while it doesn't expect any more scheduling changes, the company said, "the number of bulletins, products affected, restart information and severities are subject to change until released."