This white paper explains what makes spam such an unbearable problem and how spamming tactics are evolving daily to beat anti-spam software. In the space of two months, spammers have switched from image spam to using PDF, Excel and ZIP file attachments. By using these attachments to send images instead of embedding them in the body of the email message, spammers have taken the cat-and-mouse game with anti-spam software developers to a new level.