Microsoft has released an advisory and a stopgap fix for the zero-day vulnerability exploited by the “Duqu” Trojan, a highly targeted malware strain that some security experts say could be the most important cyber espionage threat since Stuxnet.
According to the advisory, the critical vulnerability resides in most supported versions of Windows, including Windows XP, Vista and Windows 7. The problem stems from the way Windows parses certain font types. Microsoft says it is aware of targeted attacks exploiting this flaw, but that it believes few users have been affected.
Nevertheless, the flaw is a dangerous one. Microsoft said that an attacker who successfully exploited this vulnerability could run arbitrary code, install programs; view, change, or delete data; or create new accounts with full user rights. The most likely vehicle for the exploit is a poisoned email attachment.
Microsoft is working on developing an official security update to fix the flaw. For now, it has released a point-and-click Fixit tool that allows Windows users to disable the vulnerable component. Enabling this tweak may cause fonts in some applications to display improperly. If you experience problems after applying the Fixit solution, you can always undo it by clicking “disable” image in the Microsoft advisory and following the prompts.
Update, Nov. 10, 9:22 a.m. ET: As several readers have noted, installing this FixIt may cause Windows Update to repeatedly ask prompt you to install two particular updates: KB972270, and KB982132. Uninstalling the FixIt seems to stop these incessant prompts, although it leaves the vulnerable Windows component exposed.