SEPTEMBER 22, 2004 (IDG NEWS SERVICE) - Computer code that takes advantage of a flaw in the way many Microsoft Corp. applications process JPEG images has been published on the Internet and could be a precursor to actual attacks on vulnerable PCs, experts said.

The code was published late last week, only days after Microsoft revealed the "critical" vulnerability and made patches available to fix the problem (see story). A wide range of Microsoft software that processes JPEG images, including versions of its Windows and Office products, is vulnerable.

So far, only "proof-of-concept" code that can cause a vulnerable Web browser to crash or a PC to freeze has been published. A fully developed exploit would allow an attacker to take control of a victim's computer by remotely opening a command prompt or downloading and running malicious software, one expert said yesterday.