It took less than 24 hours for attackers to crank out proof-of-concept code targeting the one critical vulnerability disclosed -- and patched -- Tuesday morning by Microsoft, security researchers warned.
To call attention to the added danger, Symantec also raised the vulnerability's threat score from Tuesday's initial 7.1 (out of a possible 10) to 8.5 today.
The Windows 2000 bug -- the only one rated critical of the four patched Tuesday -- is in Windows Agent, the component that drives the operating system's interactive animated help characters. The best known, and in its time, most detested, character was dubbed "Clippy," a.k.a. the Office Assistant, a bouncy paperclip designed to answer users' questions about Microsoft Office. The Redmond, Wash. developer disabled Clippy by default as of Office XP, and put it to rest when Office 2007 debuted earlier this year.
Symantec advised users who were unable to immediately apply the patch to disable their browser's script-handling capabilities. "A successful exploit requires the execution of active content," its advisory said. "To mitigate against this and other latent vulnerabilities, disable support for active content in the browser."
VeriSign Inc. iDefense, which was credited by Microsoft for reporting the bug, also posted an advisory today; in it, the security vendor spells out how to set the "kill bit" in the Windows registry to disable the Agent ActiveX control.
Microsoft has posted its technical write-up of the Agent vulnerability in the MS07-051 security bulletin.
Tuesday's update is also a replacement for an earlier April fix of Agent, an indication that the company's developers didn't find all the bugs in the component five months ago.
This story, "Exploit Code for Microsoft Agent Bug Appears" was originally published by Computerworld.