Mittwald says an attacker entered his MCP server for AI and compromised 56 projects

Mittwald CM Service, a German agency web hosting company, has on its blog that an attacker exploited a vulnerability on its MCP (Model Context Protocol) server, the tool that allows customers to connect AI assistants to its mStudio management platform. According to the company, it forensically analyzed 56 committed projects and treats all data as committed since October 27.

According to Mittwald's chronology, the attacker first tested the vulnerability on the night of October 21, moved as a normal user from October 23 and targeted it on October 27 at 15:03, after registering a new account. The company detected the abnormal behavior on November 4, blocked the attacker's first account at 11:11, disconnected the MCP server and came to temporarily shut down access to mStudio and SSH access to the projects. Mittwald says the customers’ websites remained accessible throughout the incident.

The company says its records show that the attacker advanced through the system “extremely fast,” with just seconds between steps that would take a person a lot more, which according to Mittwald indicates the use of AI tools.The Record notes that Mittwald has not provided other evidence of that AI intervention and that he did not immediately respond to whether he could distinguish it from the use of conventional scripts.

According to Mittwald, mStudio and SSH accesses were back available on November 7, the websites blocked for caution are still blocked for now and no more activity of the attacker has been detected. The company says it has informed competent authorities, works with external forensics and announces a detailed report for this week. It has not been specified whether the failure was in Mittwald’s own code or in MCP’s open-source libraries.