Mcpsec

• Outcome: Review
• Latest audit: May 29, 2026 · 9:28 PM UTC
• Version: 1.0.4

Overview

The skill appears to be a legitimate MCP configuration scanner, but its automated install path can place a downloaded external binary into a system PATH location without enforcing the advertised checksum verification.

Review before installing. Prefer the documented manual pinned SHA256 check, Homebrew from a source you trust, or building mcpsec from source; avoid using the automated binary install one-liner unless it is changed to verify the pinned checksum before extraction and installation. Run the scanner only on MCP configs you intend to audit, especially if they contain tokens.

SkillSpector

By NVIDIA

Vulnerability Patterns

• Supply Chain: Unpinned Dependencies, External Script Fetching, Obfuscated Code
• Tool Misuse: Tool Parameter Abuse, Chaining Abuse, Unsafe Defaults
• MCP Least Privilege: Underdeclared Capability, Wildcard Permission, Missing Permission Declaration
• Prompt Injection: Instruction Override, Hidden Instructions, Exfiltration Commands
• Data Exfiltration: External Transmission, Env Variable Harvesting, File System Enumeration

Findings (4)

Lp3

Medium

• Category: MCP Least Privilege
• Confidence: 91% confidence
• Finding: The skill declares no permissions while explicitly embedding shell-based install commands and describing execution of an external binary. This mismatch can mislead users or enforcement systems about the skill's actual capability boundary, increasing the chance of unsafe approval or execution in environments that rely on declared permissions.

External Script Fetching

Low

• Category: Supply Chain

Content

"id": "binary",
              "kind": "shell",
              "label": "Install mcpsec (pre-built binary, Linux/macOS) — verify checksum before running",
              "cmd": "curl -L https://github.com/pfrederiksen/mcpsec/releases/download/v1.0.0/checksums.txt && curl -L https://github.com/pfrederiksen/mcpsec/releases/download/v1.0.0/mcpsec_1.0.0_linux_amd64.tar.gz -o /tmp/mcpsec.tar.gz && sha256sum /tmp/mcpsec.tar.gz && tar -xzf /tmp/mcpsec.tar.gz -C /tmp/ && mv /tmp/mcpsec /usr/local/bin/mcpsec",
            },
          ],
      },

• Confidence: 88% confidence
• Finding: This finding is substantively the same risky behavior: the skill instructs downloading and then handling an external executable artifact from GitHub. Even though the documentation warns about checksum verification, the install command sequence still normalizes retrieval of untrusted code from the internet into a local executable path.

External Script Fetching

Low

• Category: Supply Chain

Content

"id": "binary",
              "kind": "shell",
              "label": "Install mcpsec (pre-built binary, Linux/macOS) — verify checksum before running",
              "cmd": "curl -L https://github.com/pfrederiksen/mcpsec/releases/download/v1.0.0/checksums.txt && curl -L https://github.com/pfrederiksen/mcpsec/releases/download/v1.0.0/mcpsec_1.0.0_linux_amd64.tar.gz -o /tmp/mcpsec.tar.gz && sha256sum /tmp/mcpsec.tar.gz && tar -xzf /tmp/mcpsec.tar.gz -C /tmp/ && mv /tmp/mcpsec /usr/local/bin/mcpsec",
            },
          ],
      },

• Confidence: 88% confidence
• Finding: This finding is substantively the same risky behavior: the skill instructs downloading and then handling an external executable artifact from GitHub. Even though the documentation warns about checksum verification, the install command sequence still normalizes retrieval of untrusted code from the internet into a local executable path.

Chaining Abuse

High

• Category: Tool Misuse

Content

"id": "binary",
              "kind": "shell",
              "label": "Install mcpsec (pre-built binary, Linux/macOS) — verify checksum before running",
              "cmd": "curl -L https://github.com/pfrederiksen/mcpsec/releases/download/v1.0.0/checksums.txt && curl -L https://github.com/pfrederiksen/mcpsec/releases/download/v1.0.0/mcpsec_1.0.0_linux_amd64.tar.gz -o /tmp/mcpsec.tar.gz && sha256sum /tmp/mcpsec.tar.gz && tar -xzf /tmp/mcpsec.tar.gz -C /tmp/ && mv /tmp/mcpsec /usr/local/bin/mcpsec",
            },
          ],
      },

• Confidence: 93% confidence
• Finding: The chained shell command combines download, verification, extraction, and installation into one pipeline, reducing opportunities for human review and making unsafe progression more likely. Worse, the command shown uses `sha256sum` without comparing against the pinned expected hash, so the chain can continue even if the downloaded artifact is malicious or simply unexpected.

VirusTotal

61/61 vendors flagged this skill as clean.

Static analysis

No suspicious patterns detected.