Malvertising is not something organizations normally associate with cyber espionage. But new research from Invincea may change that.
In a report, the security firm outlined an advanced persistent threat (APT) campaign it has dubbed "Operation DeathClick," targeting the US defense industry. Invincea has spotted more than two dozen micro-targeted attacks since September that are linked to the campaign. The objective of these attacks is likely intellectual property theft -- not ad fraud -- leading researchers to believe the perpetrators are advanced threat actors.
Within the last six months, the company has discovered and stopped targeted malvertising attacks against specific companies -- particularly those in the defense industry, according to the report.
"The combination of traditional cyber crime methods (malvertising) with targeted attacks against defense industrials for theft of IP represents another development in the ongoing blending of techniques from cyber crime and advanced threat actors with nation state agendas," the report says.
Traditional malvertising is used for click fraud, says Pat Belcher, director of security analytics at Invincea.
"In this campaign, the attacks appear intended to establish a remote persistent beachhead for the attackers into the defense/aerospace company networks," he says. "The types of malware we've seen in Operation DeathClick are typically backdoor trojans and attempts to enroll hosts in botnets. If a beachhead had been successfully established, the attackers would most likely move laterally across the network and perform other malicious actions, up to and including exfiltration of data."
The campaign uses what Invincea calls a micro-targeting system that utilizes IP address ranges, geographically narrowed-down ZIP codes, and information about user interests to target specific companies, types of companies, and user interests. The attackers are also using real-time bidding (RTB) to guarantee malicious ad delivery to the intended targets of the campaign. In real-time bidding, advertising buyers bid on an impression. If the bid is won, the buyer's ad gets displayed on the publisher's site.
"RTB micro-targeting can easily, and likely has already, replaced watering hole style attacks," says Belcher. "Why bother to compromise specific sites and wait for your target to visit when you can self-host an exploit kit and point a malvertizing cannon at your intended victim directly? It's easier, cheaper, and the likelihood of getting caught is much, much lower."
According to Invincea, the attackers redirect their ads for just minutes at a time and then abandon their exploit kit pages forever. As a result, list-based threat intelligence feeds are ineffective against them. In addition, the domains used do not appear in any proxy blacklist, and the malware droppers delivered by the exploit pages always employ different signatures, thereby evading traditional network and endpoint detection technology.
"Anyone can sign up to participate in real-time bidding anonymously and fund their campaigns from third-party payment providers such as PayPal," Belcher says. "Advertisers, and thus, malvertisers, are able to win bids that will point to normal ad content or redirect to self-hosted landing pages that are only online for minutes at a time."
For each winning ad bid, there is an ad bidder that can be tracked by his unique user ID or campaign profile, he says. However, since anyone can sign up for real-time ad bidding anonymously, the best that could be hoped is known malicious bidders could have their accounts suspended -- but even then, an attacker could re-register and start a new campaign under a different username.
The full report can be read here.