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Security: mtwuser/zero-cloud-gravity

Security

SECURITY.md

Security Policy (NIST CSF 2.0 + OWASP ASVS + MCP-Sec)

ZeroCloudGravity (zero-cloud-gravity) treats capability security, path containment, and read-only MCP isolation as foundational architectural invariants.

Supported Versions

Security patches are maintained for the active 1.x release line:

Version Supported Notes
1.0.x Yes Current Sovereign Zero-Cloud Node & zcg-mcp baseline.

Built-In Security Controls

Every ZeroCloudGravity node enforces five defense-in-depth rings across CLI, hooks, MCP, and container boundaries:

Control Plane Mechanism Concrete Enforcement
1. Path Containment Path.resolve().is_relative_to(root) Blocks .. traversal, symlink escapes, and unauthorized root reads with PATH_CONTAINMENT_VIOLATION in identity.py and node_base.py.
2. Read-Only zcg-mcp Capability Rings (R0..R2, 0 W tools) ZeroCloudMCPServer exposes strictly read-only inspection, capsule compaction, and sandboxed fork tools (mcp_security_mode: "strictly-read-only-path-contained").
3. Ephemeral Sandboxes chmod 0o555 + TTL Reaper Ephemeral Department Bots (spawner.py) materialize read-only (0o555/0o444) sandboxes with bounded TTLs and zero write capabilities.
4. Cryptographic Capsules HMAC-SHA256 + SHA-256 Receipts rcap1 capsules (codec.py) authenticate ZCG_RESONANCE_KEY frames and detect source tampering via CITATION_DRIFT_DETECTED (citations.py).
5. Lifecycle Hook Guard PreToolUse (pre_tool_guard.py) Deterministic Antigravity hook (pre_tool_guard.py) blocks automated mutating Git commands, destructive shell patterns, and protected rule overwrites.

Subprocess & Container Hardening

  • Zero Shell Interpolation: Python modules execute external binaries (git, xdg-open, verification scripts) strictly as argument lists with shell=False.
  • Non-Root Container: Dockerfile runs zcg-mcp under an unprivileged zcg user (UID 10001) with ZCG_NO_BROWSER=1 and zero network ports exposed.
  • Zero Secrets in Git: Never commit API keys, ZCG_RESONANCE_KEY secrets, or private organizational identifiers; inject credentials exclusively via runtime environment variables or Google Cloud Application Default Credentials (IAM/ADC).

Reporting a Vulnerability

Please do not open public GitHub issues for suspected security vulnerabilities:

  1. Report vulnerabilities privately via GitHub Security Advisories.
  2. Include affected module paths, reproduction inputs, and expected vs. observed capability boundaries.
  3. Maintainers acknowledge reports within 72 hours and publish coordinated fixes with regression unit tests.

There aren't any published security advisories