CWmike writes "Just hours before Adobe is slated to deliver the latest patches for its popular PDF viewer, ScanSafe announced that by its counting, malicious Adobe Reader documents made up 80% of all exploits at the end of 2009. In the first quarter of 2009, malicious PDF files made up 56% of all exploits tracked by ScanSafe. That figure climbed above 60% in the second quarter, over 70% in the third and finished at 80% in the fourth quarter. Mary Landesman, a ScanSafe senior security researcher, said, 'Attackers are choosing PDFs for a reason. It's not random. They're establishing a preference for Reader exploits.' Exactly why hackers choose Adobe as their prime target is tougher to divine, however. 'Perhaps they are more successful,' she said. 'Or maybe it's because criminal attackers are human, too. We respond when we see a lot of people going after a particular product... We all want to go after that product, too. In the attacker arena, they might be thinking, 'Gee, all these reports of Adobe Reader zero-days, maybe I should get in on them too.'"