A classic post over at the F-Secure blog where some muppet "hacker" accidentally emailed out their malware generation tool and put it right into the hands of anti-virus researchers. To quote F-Secure, Hey, thanks. Keep up the good work.
On a more serious note, this tool is used to generate trojanised PDF files. So go and check that your version of Adobe Reader is up to date right now before doing anything else..