According to researchers at Adometry (formerly Click Forensics), the attack, called "ad hijacking," uses similar malware and infection delivery methods to create a network of computers aimed at committing advertising fraud through different kinds advertisements and channels.
"In the past, advertising fraudsters have mainly set their sights on the search advertising industry," said Paul Pellman, CEO of Adometry. "This is the first attack we’ve seen that coordinates advertising fraud across many different online ad channels." Rather than requiring a user to download malware via a fake antivirus program, Adometry says the ad hijacking malware injects itself into the rootkit of a user’s computer through an advertisement on a popular website. Once it infects the computer, the malware receives instructions from a host to perform multiple kinds of advertising fraud, including search hijacking, display advertising impression inflation, and video advertising fraud.
In some cases, the malware conducts "search hijacking," Adometry says. When a user enters an organic search term, the malware program redirects the browser through different ad networks and arbitrage companies. Visitors can end up on sites they had no intention of visiting, and advertisers pay for unintentional and invalid clicks.
In other cases, visitors can reach their intended destination after being rerouted through several arbitrage networks, resulting in advertisers paying for audiences they would otherwise have for free, Adometry says. In addition, the malware program can be instructed to auto-click on specific ads on certain publisher sites and networks -- even when a browser session is inactive.
The malware can also conduct "video ad fraud," in which it hijacks an organic search and redirects the user’s browser to a Web page that displays a video ad. The video plays and the advertiser is charged for the impression, which can command premiums of $30 to $50 per thousand impressions (CPM).
In addition, ad hijacking can be used to inflate display advertising impression figures, Adometry says. "Hidden in the background from the user, the malware can direct the computer’s browser to various publisher pages that show display ads in order to generate fraudulent ad impressions," the researchers say. "The user never sees these impressions, but advertisers pay full price for seemingly valid impressions because a 'real' visitor generated the traffic."
Adometry has been tracking the exploit since November. "While difficult to quantify, the frequency with which lab machines were infected indicates that tens or hundreds of thousands of computers are likely infected, generating millions of invalid clicks and advertising impressions per month," the researchers say. Most antivirus programs do not eradicate the infection, they note.
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