IE Harbors Yet Another Bug

The flaw is in an ActiveX control included with Windows 2000, Windows XP, and Windows Server, said Symantec. As with another still-unfixed vulnerability disclosed two weeks ago, the control -- WebViewFolderIcon -- can be exploited to overflow Internet Explorer's buffer, then introduce malicious code to the compromised PC. US-CERT, the federal cyber-alert agency, also issued a warning.

HD Moore of Metasploit first reported the vulnerability in July as part of his "Month of Browser Bug" project. Then, however, Moore's proof-of-concept code only demonstrated a denial-of-service that crashed the browser.

"Now that a functional exploit is available, an official patch from Microsoft will likely appear at some point in the future," Symantec said in an alert to customers.

That may be whistling in the dark, however, since Microsoft has several outstanding vulnerabilities to contend with, including the earlier ActiveX flaw and one publicized Wednesday in Microsoft Office's presentation software, PowerPoint.

Microsoft has not posted an advisory for the new flaw, and Symantec and US-CERT only suggested that users either disable Active Scripting in IE or set the "kill bit" for the ActiveX control. The latter, however, is somewhat technical and if done incorrectly, can damage the operating system.