Internet Explorer on WinXP SP2 Vulnerable to Attack (again)

A zero-day vulnerability in Microsoft's dominant Internet Explorer browser is being used in drive-by attacks against fully patched Windows XP SP2 systems, according to warnings from anti-virus vendors..

McAfee was the first to raise the alert for the attacks, warning that the exploit simply requires that a user is lured to a maliciously rigged Web page:

Preliminary tests demonstrate that Internet Explorer 6 and 7 running on a fully patched Windows XP SP2 are vulnerable to this attack. Windows XP SP0 and SP1 do not appear to be vulnerable, nor does Firefox 2.0. Exploitation happens completely silently.

According to McAfee researcher Craig Schmugar, the flaw exists in the way IE handles malformed .ani files. (The .ani file format is used to read and store Windows Animated Cursors) and can be easily placed on an attacker's Web site to trigger the vulnerability).

Multiple sources in the anti-malware community have confirmed McAfee's discovery, which includes the use of arbitrary .exe files and Trojan downloaders.