Related topics

MS probes bug that turns PCs into 'public file servers'

Unwanted promotion for older Windows boxes

Microsoft has begun investigating a flaw in IE that most affects older versions of Windows, and turns vulnerable systems into a "public file server".

The vulnerability means that hackers might be able to access files with an already known filename and location, providing they can trick users into visiting a maliciously constructed website. For this approach to work, the Protected Mode feature - which runs by default in Vista, Windows 7, and Windows Server 2008 - needs to be absent or disabled.

The bug is therefore much more of a potential concern for XP and Windows 2000 shops, whose users are potentially in the firing line even if they are running IE 8. The vulnerability has not become the target for active hacker exploitation and is unrelated to the IE flaw linked to attacks on Google and other hi-tech firms back in December.

Given the lack of active attacks, an out of sequence patch is highly unlikely. It's far more probable that Redmond will publish an update in March rather than in next Tuesday's Patch Tuesday, which doesn't allow anything like enough time to develop a patch, much less test it.

Microsoft's advisory, published on Wednesday, explains the issue in greater depth. Redmond's investigation of the bug follows a presentation of the flaw by Jorge Luis Alvarez Medina of Core Security Technologies, at the Black Hat security conference in Washington this week.

His description of the flaw, as something that "turns your personal computer into a public file server", is far more eye-catching than Redmond's description of the risk as an "information disclosure" bug.

Our earlier interview with Medina where he explains the latest IE years, the latest of several Core has reported to Microsoft over the years, can be found here. ®

Sponsored: Driving business with continuous operational intelligence