mcp-zero-trust-proxy

README

MCP Zero-Trust Proxy

A drop-in reverse proxy that adds zero-trust security to any MCP server — no code changes required.

docker run -e MCP_TARGET=localhost:3000 -e AUTH_PROVIDER=github -p 8080:8080 \
  ghcr.io/anoblescm/mcp-zero-trust-proxy

What it does

MCP (Model Context Protocol) is how AI agents connect to tools — Claude, Cursor, Copilot all use it. But authentication is optional in the spec. This proxy sits between your MCP clients and servers to enforce security:

• OAuth 2.1 PKCE — Require login via GitHub, Google, Okta, or any OIDC provider
• Tool-level RBAC — Control which tools each user can call (admin/readonly/restricted roles)
• Per-client sessions — Each user gets their own session boundary
• Audit logging — Every request logged: who, what, when, allowed/denied (structured JSONL)
• Rate limiting — Per-client token bucket (default: 300 req/min, configurable)

Why

• 8,000+ MCP servers publicly reachable with no authentication (Shodan)
• 30+ CVEs in 60 days (Jan-Feb 2026)
• CVSS 9.6 RCE in mcp-remote, the most popular OAuth workaround
• Clawdbot breach hit 1,800+ servers in 48 hours

Quick start

Docker (recommended)

# 1. Pull
docker pull ghcr.io/anoblescm/mcp-zero-trust-proxy:latest

# 2. Create config.yaml
cat > config.yaml <<EOF
server:
  upstream_url: "http://host.docker.internal:3000"
  listen_addr: ":8080"
auth:
  provider: "github"
  client_id: "your-github-client-id"
  client_secret: "\${OAUTH_CLIENT_SECRET}"
  redirect_url: "http://localhost:8080/auth/callback"
roles:
  - name: "admin"
    allowed_tools: []
  - name: "readonly"
    allowed_tools: []
audit:
  enabled: true
  output: "stdout"
EOF

# 3. Run
docker run -p 8080:8080 \
  -v ./config.yaml:/etc/mcpproxy/config.yaml \
  -e OAUTH_CLIENT_SECRET=your_secret \
  ghcr.io/anoblescm/mcp-zero-trust-proxy:latest \
  --config /etc/mcpproxy/config.yaml

# 4. Verify
curl http://localhost:8080/health
# {"status":"ok"}

Binary

go install github.com/AnobleSCM/mcp-zero-trust-proxy/cmd/mcpproxy@latest
mcpproxy --config ./config.yaml

Or download a release binary from the releases page.

How it works

AI Client (Claude, Cursor, Copilot)
        │
        ▼
┌─────────────────────────┐
│  MCP Zero-Trust Proxy   │
│                         │
│  1. Body size check     │
│  2. Auth (OAuth 2.1)    │
│  3. Rate limit          │
│  4. JSON-RPC parse      │
│  5. RBAC check          │
│  6. Forward to upstream │
│  7. Filter tools/list   │
│  8. Audit log           │
└─────────────────────────┘
        │
        ▼
   Your MCP Server
   (unchanged)

Configuration

All config is in a single YAML file. See configs/example.yaml for the full reference.

RBAC example:

roles:
  - name: "admin"
    allowed_tools: []          # empty = all tools
  - name: "readonly"
    allowed_tools: ["tools/list", "resources/read"]
  - name: "restricted"
    allowed_tools: ["read_file", "search_files"]
    deny_tools: ["delete_file"]

user_roles:
  mapping:
    "alice@company.com": "admin"
    "bob@company.com": "readonly"
  default: "readonly"

Performance

Single binary, ~10MB. Sub-millisecond proxy overhead:

• p50: ~400us
• p95: ~900us
• Docker image: 6.6MB

Run benchmarks: ./scripts/benchmark.sh

Documentation

• Quick-Start Guide — Full setup walkthrough
• Configuration Reference — Every YAML field documented
• Multi-Tenant Setup — Docker Compose for agencies

Tests

236+ tests across 9 packages:

go test ./...
go test -race ./...  # zero data races

Contributing

PRs welcome. The codebase is standard Go — no frameworks, minimal dependencies.

1. Fork and clone
2. go test ./... to verify
3. Make your changes
4. go test ./... again
5. Open a PR

Security

Found a vulnerability? See SECURITY.md for responsible disclosure.

License

MIT