Microsoft on Sunday confirmed it's investigating an unpatched bug in VBScript that hackers could exploit to plant malware on Windows XP machines running Internet Explorer (IE).

The flaw could be used by attackers to inject malicious code onto victims' PCs, said Maurycy Prodeus, the Polish security analyst with iSEC Security Research who revealed the vulnerability and posted attack code on Friday.

Users running IE7 or the newer IE8 are at risk, said Prodeus.

Microsoft noted it's already on the case. "Microsoft is investigating new public claims of a vulnerability involving the use of VBScript and Windows Help files within Internet Explorer," said Jerry Bryant, a senior manager with the Microsoft Security Response Center (MSRC), in an e-mail Sunday. *The current state of our investigations shows that Windows Vista, Windows 7, Windows Server 2008, and Windows Server 2008 R2, are not affected."

More: http://www.computerworld.com/s/article/9163298/