Pump and Dump scam emails are slowly replacing the traditional text and images spam emails that used to fill our inboxes. In the past few days, there has been a resurgence in the number of such scams hitting our inboxes. The Pump and Dump scam is pretty simple to understand.
Criminals identify a small genuine company with (a) some 'apparent' potential (b) a real background (c) a listing on a stock exchange. After having purchased large amounts of the company's stock at rock bottom prices, they wait for shares prices to go up before selling theirs. The latest twist in the PnD saga is the fact the fraudsters are now turning to Adobe Acrobat's popular Portable Document Format (PDF) to trick spam filters.
There are 3 possible explanations as to why PnD emails now sport PDF attachement rather than images : firstly, PDF documents do carry more status than more common graphic files. Most whitepapers, Case studies and reports are published in PDF format due to the fact that PDF is a universal, multiplatform and aesthetically pleasant format.
Secondly, spam filters are probably better trained now to identify Image spam emails than ever before, which therefore encourage scammers migrating from one format to another.
Lastly, and probably a more insidious reason, is that scammers might be trying to pit email service providers against their customers over content filtering, with the hope that the latter will call their providers and ask for less aggressive content filtering. And that's what happened to me earlier this week, much to my chagrin.
So are PDF scammers going to win this round? Well, Sophos says that there's a huge PDF spam wave coming our way. Let's just cross our fingers.