In 2016 bots, scripted software programs that perform automated tasks, surpassed human beings as the primary users of the Internet, according to research from Imperva, a cybersecurity firm based in Redwood Shores, Calif. By the company’s measure, 52% of all Internet traffic was attributable to these software drones last year.

PerimeterX CEO Omri Iluz founded the cybersecurity company in 2014 in order to tackle the problem of automated bot attacks. Even he did not foresee how bad it would become, he said, citing social media spammers gaming trending news topics during the recent presidential election.

“Fake news at its core of distribution is an army of bots,” Iluz tells Fortune. “If you control a million voices, you can get anything to the top of the news.”

PerimeterX said Tuesday it had raised $23 million in new funding to take on the challenge. The company has raised a total of $34.5 million in three rounds to date.

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PerimeterX tracks the behavior of website visitors and uses artificial intelligence algorithms to determine which are bots and should be blocked. “Between a user and an application, we’re able to identify clear heuristics about what is a good intention and what is a malicious intention,” Iluz says.

By parsing patterns of activity, the company’s “bot defender” product aims to determine who is, for example, merely trying to buy something from an online shop versus who is trying to scrape the price of every item on a list. Cybercriminals rack up billions of dollars through bot-orchestrated account takeovers, click fraud, extortion schemes related to distributed denial of service attacks, and other bot-oriented scams every year.

Joydeep Bhattacharyya, partner at Canaan Partners who led the latest funding deal, said that he decided to invest after having the founders of Skycure, a mobile cybersecurity company based in Israel that was recently acquired by Symantec (SYMC), help him perform due diligence on the crew. He was pleased with the outcome.

“What PerimeterX is doing is serving as both an alarm system and the cops in the digital world,” Bhattacharyya says. “Every B2C [business to consumer] website today needs this.”

Given the extent of the bot threat, there’s no doubt PerimterX has its work cut out for it.

Existing backers Vertex Ventures and Data Collective also participated in the deal.