Google and the FBI have busted a major ad-fraud operation that hijacked almost two million devices.

A 13-count indictment unsealed on Tuesday brings charges against eight people surrounding their involvement in a digital advertising fraud scheme referred to as '3ve' and Methbot.

Not only did the scammers siphon off millions of dollars from the advertising industry, but at the height of its operation, 3ve infected about 1.7 million computers, 5,000 counterfeit websites and about 60,000 accounts with ad companies.

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A 13-count indictment unsealed on Tuesday brings charges against eight people surrounding their involvement in digital advertising fraud schemes referred to as '3ve' and 'Methbot'

WHAT ARE 3VE AND METHBOT? Methbot was a sprawling advertising fraud scheme. It involved scammers collecting false clicks on ad campaigns by linking them to false IP addresses. The operation netted the scammers as much as $5 million a day. Security vendor WhiteOps eventually shut the scheme down in 2016. Similarly, 3ve was an ad fraud operation that distributed malware on millions of devices to generate fake clicks on ad campaigns. Scammers infected some 2 million devices and created 60,000 fake accounts with digital ad companies. It raked in an alleged $29 million. Advertisement

The defendants listed in the indictment include eight nationals from Russia and Kazakhstan, while five other suspects are said to be at large.

Among the charges listed are wire fraud, computer intrusion, aggravated identity theft and money laundering, according to the indictment.

'As alleged in court filings, the defendants in this case used sophisticated computer programming and infrastructure around the world to exploit the digital advertising industry through fraud,' U.S. Attorney Richard Donoghue said in a statement.

'This case sends a powerful message that this Office, together with our law enforcement partners, will use all our available resources to target and dismantle these costly schemes and bring their perpetrators to justice, wherever they are.'

'3ve' hoped to siphon off as much as $250 billion from the ad industry.

It was unsuccessful in those efforts, but still managed to bring in an alleged $29 million.

Meanwhile, Methbot raked in about $7 million, which resulted in the schemes scamming companies out of a whopping $36 million.

Google said it created a working group comprised of Department of Homeland Security, the FBI, security software vendors and law enforcement officials to tackle the operation

The scams were first discovered by officials in 2016 and they quickly became a 'very complex, ever-shifting maze,' according to the FBI.

They spread malware packages to infect PCs in emails and downloaded files. As a result, the bots would click on ads, generating fake ad dollars for the scammers.

'3ve operated on a massive scale: at its peak, it controlled over one million IPs from both residential botnet infections and corporate IP spaces, primarily in North America and Europe (for comparison, this is more than the number of broadband subscriptions in Ireland),' Google wrote in a paper describing the findings.

'It featured several unique sub-operations, each of which constituted a sophisticated ad fraud scheme in its own right.

'Shortly after we began to identify the massive infrastructure (comprised of thousands of servers across many data centers) used to host 3ve's operation, we found similar activity happening within a network of malware-infected residential computers,' the firm continued.

3ve spread malware packages to infect PCs in emails and downloaded files. As a result, the bots would click on ads, generating fake ad dollars for the scammers

Not only did the scammers siphon off millions of dollars from the advertising industry, but at the height of its operation, 3ve infected about 1.7 million computers, 5,000 counterfeit websites and about 60,000 accounts with ad companies

In some cases, average internet users encountered these fake ads.

The scammers went to great lengths to have their bots simulate real internet activity, by having them open and play videos, among other things.

Some of the defendants outlined in the indictment were involved in Methbot, which was reportedly shut down in December 2016, as well as 3ve, which continued running until October 2018.

Google said it created a working group comprised of Department of Homeland Security, the FBI, security software vendors and law enforcement officials to tackle the operation.

'We had to shut the operation down for good, which called for greater, more calculated measures,' Google explained.

'To that end, it was critical that we played the long game, endeavoring to have a more permanent, more powerful impact against this and future ad fraud operations.'