Spammers use modified PDF files to avoid detection

thefickler writes: In the continuing effort to get more spam past email filters, professional spammers are not only stepping up their use of PDF attachments to deliver their offers of penile implants and cheap pharmaceuticals, but they are also modifying the PDFs to avoid detection. Worse yet, the chief security analyst at MessageLabs, Mark Sunner, has suggested that PDF attachments might soon be used by spammers to delivery malware.