One hacker used AI agents to break into more than 100 company websites

Reuters reported Monday that a Chinese-speaking hacker broke into sites belonging to more than 100 companies, including Deere, SharkNinja and Cummins, and AI agents did almost all of the work. NorForge researcher Snorre Fagerland watched it happen through control panels for Cairn, an open-source AI agent platform, that the attackers had left open on the web. The agents tried more than 1,200 sites, and a successful break-in typically took about 23 hours. Fagerland estimates the campaign cost about $5,000 in AI tokens, roughly $50 per successful hack. NorForge found more than 20 exposed Cairn panels it believes are malicious. It says the agents appear to have run DeepSeek's cheap V4.1 Flash model inside a Claude Code-style setup.

What this means for you: a serious break-in attempt now costs pocket change, so small online shops are worth an attacker's time. Keep store platforms such as Magento patched, lock down admin panels and anything else exposed to the internet, and rotate reused passwords and API keys. The companies say the damage was limited. Deere saw "no indication that sensitive information was accessed," SharkNinja says a standalone support site was hit and the threat contained, and Cummins is investigating a site run by a vendor. Reuters couldn't confirm how much data was taken. Cairn's creator says the tool wasn't built for hacking.