Pdf spamming
Although spammers registered considerable success with image spam (picture, right) the anti-spam software industry had not lost the battle and quickly came out with new counter-measures to stop image spam. Realizing that filters had a problem with images, the answer was to hit spammers at source – that is where the email originated from. This new approach had an immediate positive result and considerably decreased the effectiveness of image spam and gave back to email users some control over their mailbox. As with every cat-and-mouse game, spammers had to respond and in June 2007, they came up with a new technique that is not only ingenious but even more problematic than image spam. Instead of embedding the image within the email itself, they ‘repackaged’ it within an attachment using one of the most common file formats in use today – a PDF file.