Over the last couple of days we've been noticing a few pharmacy spam mails which are a bit different. Somebody seems to have replaced the original graphical content with an alert highlighting that such messages are malicious.
So far we have counted three (ab)used image hosting services for this spam:
A quick analysis of these showed that #1 currently serves all the replaced images, #2 serves all original spammers images and #3 seems to have removed the offensive content immediately, good work!
At the moment, we don't have any further information about the source/background of the warning replacements - this gives us plenty of opportunity to use our imaginations when thinking about what's actually going on. A few of the key words and concepts we're considering are: white hats, rival spammers, compromised hosting service(s). Not an exhaustive list, but more of a launch pad for further theories and research!