According to Reuters, financial firms have been warned about the possibility of al Qaeda cyber attacks. CNN did a short blurb to chime in. And the SANS Internet Storm Center stated it this way: US DHS banking alert.

And I quote Johannes Ullrich (SANS): "My short take on it: Make sure you follow best practices and keep your guard up. Its probably not going to be Al Qaeda, but someone will probe your defense tomorrow as they did today. And whatever helps against them will help if Al Qaeda should launch a cyber attack after all."