One hacker and AI agents: more than 100 breached sites for about $5,000

On October 19, Reuters published an investigation into an attack carried out almost entirely by AI agents. It is based on a report by Snorre Fagerland, a researcher at NorForge.

According to NorForge, a Chinese-speaking attacker used Cairn, an open-source AI agent platform: you give it a goal, and the agents find their own way to it. The campaign targeted online stores in the US, Canada, Australia and Japan. The agents tried to break into more than 1,200 sites and, by the researcher's estimate, got into more than 100. The instructions for the whole campaign fit in fewer than 100 Chinese characters. Judging by the worker name in the tasks, the agents ran through Claude Code on DeepSeek's low-cost V4.1 Flash model, though this is NorForge's assumption.

What the agents did

The agents looked for a way to run code on a site and then planted a hidden file upload form. The researchers believe the aim was long-term access to store and payment systems. A successful attack took just under 23 hours on average.

Reuters named Deere, SharkNinja and Cummins among the victims. Deere and SharkNinja said they had dealt with the threat; at SharkNinja a standalone support site was hit. Cummins is investigating a possible attack on a vendor's website. Reuters could not establish whether any data was taken.

Fagerland roughly estimates model costs at about $5,000, or around $50 per successful breach. The campaign was exposed by Cairn control panels left open on the internet: NorForge found them with ordinary internet scanning.

The point is not the dollar amount but the scale one person can now reach. A campaign like this used to take a team and weeks of work. Now a short instruction and a budget comparable to a laptop were enough.

For businesses the lesson is practical: any site reachable from the internet is a target, not only big companies. Forgotten support sites, old admin panels, vendor services: an agent will check them all. But it works both ways: the same scanning tools helped researchers find the campaign. This continues the topic I wrote about yesterday.

Sources: Reuters, The Next Web.