New to this? Read it in simple words
- One hacker used AI agents to attack more than 1,200 websites, a researcher says.
- More than 100 companies were broken into, including a site of the farm machine maker Deere.
- The hacker spent about $5,000 on AI, the researcher estimates.
- Deere and SharkNinja say the damage was contained.
- AI agent
- An AI program that carries out tasks by itself, step by step, instead of only answering questions.
- Control panel
- A web page where someone starts tasks and watches how they are going.
- Breach
- When an attacker gets into a computer system without permission.
Cairn is a tool that sends many AI agents to work on tasks at once, and shows their progress in a web panel. Its author says it was not made for hacking. NorForge, a security company in California and Norway, went looking for Cairn panels that anyone could open.
What the researcher found
NorForge published its report on October 19. It found more than 20 open Cairn panels that it judged likely to be used for attacks, in three groups. The largest group, with 14 panels, was run in Chinese and held over 1,100 attack projects.
The campaign began on September 25, Reuters reports. By late last week it had targeted more than 1,200 websites in the US, Canada, Australia and Japan. More than 100 companies were breached, Fagerland told Reuters.
“It’s not script kiddie stuff,” Fagerland told Reuters. A successful attack took a little under 23 hours, according to both Reuters and the report.
From NorForge’s report and Reuters. The breach count and the cost are the researcher’s estimates.
Which AI did the work
Every task in the Chinese-language group ran on a worker named “claudecode_deepseek-v4.1-flash”. NorForge says this could mean Anthropic’s Claude Code tool running DeepSeek’s V4.1 Flash model. That is its reading of a name, not a confirmed fact.
Fagerland estimates the hacker spent about $5,000 on AI fees, or about $50 for each successful break-in. NorForge’s report says its cost figures are uncertain, because it could not see the hacker’s bills.
The author of Cairn wrote on X that the tool was “not designed for hacking attacks”, Reuters reports. Anthropic and DeepSeek have not commented in any of the reports.
What the companies say
NorForge’s report names no victims. Reuters found the names by reviewing the hacker’s records itself.
Deere told Reuters it had “no indication that sensitive information was accessed”. SharkNinja said the attack hit a separate product support website and had been contained.
Cummins said it was looking into a possible attack on a website run by one of its outside vendors, a statement it also gave The Verge. Reuters could not find out whether any data was taken.
Sources
Every fact in this story comes from the sources below. Open them to check our work.
- 1Primary source · October 19, 2026Inside Cairn: Open Windows into massive AI-Driven Cyber Operations NorForge
- 2Research · October 19, 2026Exclusive: How one hacker used AI agents and a few thousand dollars to break into scores of sites Reuters (via AOL)
- 3Research · October 19, 2026A hacker broke into John Deere and SharkNinja with an army of AI agents The Verge
- 4Research · October 19, 2026AI agents broke into 100+ sites for one hacker at $50 each, researcher says The Next Web
The count of more than 100 breaches and the cost are the researcher’s estimates. The victims’ names come from Reuters’ own review and the companies’ statements, and no outlet has confirmed the break-ins separately.
One hacker used AI agents to attack over 1,200 websites and breach more than 100 companies for about $5,000. How we rate the mood