Microsoft Warns of Zeroday XML Core Services Vulnerability

During their already busy Patch Day, Microsoft snuck out a security advisory warning their customers that attackers are  exploiting a previously undiscovered vulnerability in XML Core Services to launch drive-by download attacks in the wild.

Microsoft’s XML Core Services (MSXML)  is basically a component that helps Windows, Internet Explorer, and other Microsoft products to handle XML content. XML Core Services ships with various versions of Windows, and many other Microsoft products. If you have a Windows computer, you probably have XML Core Services installed.

According to the security advisory, XML Core Services suffers from an unpatched memory corruption vulnerability, which attackers can exploit to execute code on your machine. The attacker only has to lure you to a web site containing maliciously crafted code for his attack to succeed.

Since Microsoft first learned of this vulnerability through actual attacks in the wild, they haven’t had time to create and release a full patch yet. However, they have released what they call a “Fixit“, which is supposed to block this particular attack vector. If you manage a Microsoft network, I recommend you apply this Fixit on your Windows machines.

I’ll be sure to update you when Microsoft releases the real patch in the weeks or months to come. — Corey Nachreiner, CISSP (@SecAdept)

About Corey Nachreiner

Corey Nachreiner has been with WatchGuard since 1999 and has since written more than a thousand concise security alerts and easily-understood educational articles for WatchGuard users. His security training videos have generated hundreds of letters of praise from thankful customers and accumulated more than 100,000 views on YouTube and Google Video. A Certified Information Systems Security Professional (CISSP), Corey speaks internationally and is often quoted by other online sources, including C|NET, eWeek, and Slashdot. Corey enjoys "modding" any technical gizmo he can get his hands on, and considers himself a hacker in the old sense of the word.


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