German web host breached through AI assistant connector, with attacker possibly using AI tools

Mittwald CM Service, a North Rhine-Westphalia hosting provider for web agencies, disclosed that attackers compromised 56 customer projects and stayed undetected on its systems for eight days. Managing director Robert Meyer said the attackers exploited a flaw in the company's Model Context Protocol (MCP) server, which lets customers connect AI assistants to mStudio, its platform for managing websites and hosting services. It is unclear whether the flaw sat in Mittwald's own code or in the open-source MCP software libraries it relies on.

Meyer said the attacker appeared to use AI tools. Logs showed the intruder moved through the system extremely quickly, sometimes with only seconds between steps that would take a human much longer. However, Mittwald offered no other evidence of AI involvement, and did not immediately explain how it distinguishes AI tools from conventional scripts that also speed up attacks. The timeline shows the attacker first tested the flaw in October, during a global rush to patch a separate vulnerability known as PHP2Shell, and used diversionary tactics to disguise access attempts.

External forensic experts are supporting the analysis and the authorities have been informed. After examining the 56 affected projects and repeatedly scanning its own systems, Mittwald said that as of Friday it could detect no further attacker activity. It plans to publish a detailed account of the events once analysis and recovery are complete.