AI agents used to breach more than 100 company websites in under a month
AI agents helped a hacker breach over 100 company sites in under a month; Deere and SharkNinja were among targets.
Fagerland found the operation while looking for exposed Cairn installations and discovered about two dozen being used for malicious purposes, TechRadar reported. The autonomous agents tested vulnerabilities, adapted their tactics and established access with minimal human input, according to the report.
Cairn is an open-source, general-purpose AI problem-solving engine designed to help autonomous agents find solutions to complex tasks. Rather than focusing on a single application, it provides a framework that defines goals, explores different approaches and executes actions to try to solve a problem. TechRadar said Cairn is popular in the cybercriminal community, although it is not malicious by design.
According to Fagerland, the 'problem' Cairn was asked to solve was how to run code on a website without signing in. The agents tried SQL injection, file uploads and unsafe handling of stored objects, with the goal of establishing persistent access to shopping and payment systems that could later be used to steal money. Fagerland said the attacker likely used Claude Code with a DeepSeek model, though attribution is difficult. Instructions were generally fewer than 100 Chinese characters. In less than a month, the agents tried more than 1,200 sites, spending an average of 23 hours on each before breaking in or moving on. With about 100 successful break-ins, the hacker paid an estimated $50 in tokens per breach, or about $5,000 in total; Fagerland said the billing figure was an estimate, not confirmed.
Fagerland did not name the victims. Cybersecurity News said they were mainly online stores in the United States, Canada, Australia and Japan. Reuters, after independently reviewing the hacker's Cairn activity, confirmed Deere, the farm equipment maker; SharkNinja, the home appliance company; and Cummins, the engine manufacturer, as targets, TechRadar reported. Two smaller businesses acknowledged being compromised but did not answer Reuters' inquiries, according to the report. Deere said it took 'necessary remediation actions' and saw 'no indication that sensitive information was accessed.' SharkNinja said the breach affected a standalone site carrying product support information only and that the threat had been remediated. Cummins said it was looking into the reports.
No one knows whether the attacker stole sensitive data or how much, according to the report. Fagerland found 'hundreds' of exposed secrets in open panels and was working with Reuters to notify victims.
Fagerland said he was 'impressed' by some of the techniques the agents used. After hitting a dead end against one target, the agents scanned digital records for associated infrastructure and found a public-facing control panel with a 'subtle weakness' in how it processed data. They spent hours on trial and error before executing a malicious command on the website's server, he said. 'It's not straightforward to come up with solutions like that,' Fagerland said. 'It's not script kiddie stuff.'
Business owners were advised to patch public-facing applications, restrict access to admin panels and monitor web directories for unexpected files, according to TechRadar.