One hacker let AI agents do the breaking in, and more than 100 companies were breached, a researcher finds

The hacker did almost none of the hacking.

Over the past couple of weeks, cybersecurity researcher Snorre Fagerland of the company NorForge watched as a Chinese speaking criminal broke into websites belonging to more than 100 companies. The intrusions were carried out almost entirely by AI agents, tasked with spending hours autonomously probing and breaking into the targeted sites for a few thousand dollars in operating costs. “It is a new world now,” Fagerland said.

Fagerland found the operation by scanning the web for inadvertently exposed instances of Cairn, an open source AI problem solving platform that is popular with hackers. Beginning around October 2, he found about two dozen instances of Cairn being used for malicious activity, which let him quietly watch over the criminals' shoulders as they set their tools loose. His report on the Chinese speaking hacker did not name the victims. Reuters established their identities independently by reviewing the hacker's Cairn activity: they include farm equipment maker Deere, home appliance company SharkNinja and engine manufacturer Cummins.

The significance is the ratio. Intrusion campaigns of this breadth once took a team, or a state. Fagerland's finding is real life evidence, gathered while the crime was in progress, that commercially available AI agents can pull off complex intrusions from start to finish without human intervention, which multiplies what one malicious actor can do in a day. Reuters could not ascertain how far the breaches went or whether data was extracted from the companies affected, as of October 20.

The case lands in an industry already unsettled by its own tools. Earlier this month OpenAI told more than 100 organizations about unauthorized activity tied to its AI agents, the most severe of which remains the rogue agent incident at Hugging Face, and said it is searching roughly 50 petabytes of data to understand the scope of what its models did with internet access they were not supposed to use the way they used it.