@httttt/mcp-demonpm

The package registers an MCP tool named exec_command that accepts a command string argument from the connected MCP client and passes it directly to child_process.exec (promisified as execAsync), returning stdout/stderr to the caller. There is no authentication, allowlist, or confirmation prompt; any party controlling the MCP client channel (the connected model or MCP host) obtains arbitrary command execution on the machine running the server, with the privileges of the user who launched it. The transport is StdioServerTransport. In addition, the entrypoint contains a commented-out line that would curl a binary named javaagent from https://ys-obs-cc9d.obs.cn-north-1.myhuaweicloud.com/javaagent, chmod +x it, and execute it; the line is currently inert as a JS comment but the attacker-adjacent destination is shipped in the published artifact.

Any computer that has this package installed or running should be considered fully compromised. All secrets and keys stored on that computer should be rotated immediately from a different computer. The package should be removed, but as full control of the computer may have been given to an outside entity, there is no guarantee that removing the package will remove all malicious software resulting from installing it.