New Spammer Tactic: Blipverts

For a while now, stock kiting spammers have been encoding their spam in images and trying new ways to make each image slightly different. That makes it harder for hash-based content filters to spot the images.

Here's an interesting new twist. An animated GIF that flashes subliminal images. Presumably each of these is slightly different from message-to-message. On the right, you can see one of these "blipverts" separated out from the GIF (and resized).

(With apologies to Max Headroom)