The Tag Barnakle malvertising group is hacking into Revive ad servers to inject and deliver malicious advertisements on unwary visitors. Most online publishers use hosted ad server platforms such as Google Ad Manager to deliver their ads. Confiant security researcher Eliya Stein told BleepingComputer that fake Adobe Flash player updates install the Shalyer Trojan or other botnet bundlers onto Mac users’ Mac computers. In one compromised RTB ad provider, Confiant saw up to 1.25MM malicious ad impressions being pushed out in a single day.
Source: https://www.bleepingcomputer.com/news/security/revive-ad-servers-being-hacked-to-distribute-malicious-ads/