Online advertisements can be an annoying interruption to our normal browsing habits. However, they are often necessary because they serve as the primary funding source for the otherwise free websites we use daily. Ever wonder how those ads end up on your screen? Well, there’s a fascinating supply chain behind the ads, and it’s interesting to pick apart.
Typically, a website that serves ads does not hand-pick the specific advertisements displayed on its platform. Instead, it chooses ad categories to block, allocates ad space, and then displays whichever ads its advertising vendor provides. Advertisement vendors are responsible for sourcing advertisers and websites to display their advertisements. But what if those advertisers aren't legitimate? What if they're threat actors or scammers looking to lure potential victims with seemingly legitimate software or help fixing your computer? This malicious use of ads is referred to as malvertizing.
