The "active exploit" takes advantage of a vulnerability in QuickTime v.7.x that could lead to users downloading Trojan software. The vulnerability reportedly lies in a boundary error when QuickTime processes Real Time Streaming Protocol (RTSP) replies.
Hamada said the exploit code was found on a compromised porn site that redirects users to a site hosting malicious software called "Downloader." Downloader is a Trojan that causes compromised machines to download other malicious software from the Internet. Symantec rates Downloader as "very low" risk.
Symantec is advising concerned IT professionals to:
Look for a patch for this nasty soon.