Hacker Used AI Agents to Breach Over 100 Company Websites for About $5,000, Report Says

A Chinese-speaking hacker broke into the websites of more than 100 companies, including farm equipment maker Deere, home appliance company SharkNinja and engine manufacturer Cummins, while doing almost none of the work personally, according to research reported by Reuters.

The hacker outsourced the intrusion campaign almost entirely to artificial intelligence, tasking AI agents with spending hours autonomously probing and breaking into targeted sites, said Snorre Fagerland, principal threat researcher at cybersecurity firm NorForge.

Fagerland provided his report to Reuters ahead of its publication on Monday. He said he began finding instances of malicious use of Cairn, an open-source AI problem-solving platform, around Oct. 2 while scanning the web for inadvertently exposed installations. About two dozen instances were being used for malicious activity, which let him watch the attackers operate.

How the campaign worked

Beginning Sept. 25, the hacker set the AI agents loose against e-commerce websites in the United States, Canada, Australia and Japan. The agents attempted to break into more than 1,200 sites, Fagerland said, with successful intrusions typically taking about 23 hours of probing for weaknesses.

The hacker’s instructions were brief, describing the preferred intrusion tactics in fewer than 100 Chinese characters, Reuters reported. A typical task told the agents to find a way to run code on a shop and then plant a web shell uploader, which attackers can later swap for something more damaging.

Fagerland estimated the campaign used a mix of China’s DeepSeek and Anthropic’s Claude Code and chewed through roughly $5,000 worth of AI tokens, or about $50 per successful hack.

“It’s a new world now,” Fagerland said. He told Reuters the case was real-life evidence that commercially available AI agents could carry out complex intrusions from start to finish without human intervention.

“It’s not straightforward to come up with solutions like that,” Fagerland said of the techniques he saw. “It’s not script kiddie stuff.”

What the targeted companies said

Fagerland’s report did not name the victims, but Reuters established their identities by independently reviewing the hacker’s Cairn activity. Reuters said it could not determine how much data, if any, was taken.

Deere told Reuters it had taken “necessary remediation actions” and had “no indication that sensitive information was accessed.” SharkNinja said the intrusion hit a standalone site carrying only product support information and that the threat had been contained. Cummins said it was “investigating the report of a potential cyber-attack on a website operated by one of our third-party vendors.” Two smaller businesses also acknowledged being compromised, Reuters reported.

Other hackers Fagerland observed were running similar AI-driven campaigns. One stole a trove of credit card data, and another tried to get AI agents to rob a cryptocurrency exchange, Reuters reported.

Cairn’s author, who posts under the handle “le1xia0,” acknowledged a Reuters request for comment but did not answer its questions, Reuters said. In a recent post on X, the author said the platform was “an innovative type of multi-agent architecture and was not designed for hacking attacks. If it is used to carry out harmful hacking attacks, that is not my intention.”

Reporting based on coverage by Reuters.