The Rogue Server Problem: What MCPHammer Reveals About MCP Trust

The Rogue Server Problem: What MCPHammer Reveals About MCP Trust Praetorian recently published MCPHammer — a toolkit that demonstrates something the MCP community hasn't fully grappled with yet. The threat isn't just exposed servers. The threat is servers that look legitimate. I've been cataloging public MCP servers for seven months. My dataset now covers 535 servers. 200 have no authentication. 187 expose tools to anyone who connects. That number has occupied most of my attention. MCPHammer shifted the frame. What MCPHammer Actually Is MCPHammer isn't a scanner that attacks MCP servers. It's a rogue MCP server — one designed to look legitimate while doing something different. Its capabilities: append custom text to every tool response (prompt injection), collect telemetry about any host that runs it, download and execute arbitrary files via a tool call, and accept remote commands through a management server that can update injection text in real time across multiple deployed instances