Tcha MCP Firewall
In-line transport firewall standing between Claude (or any MCP host client) and tool execution servers. Enforces deterministic boundary policies in under 1 millisecond.
Policy Enforcement Matrix
| Threat Vector | Attack Pattern | Firewall Action |
|---|---|---|
| Cloud Metadata SSRF | http://169.254.169.254/..., metadata.google.internal | DENIED (403) — IP range blocked |
| Path Traversal | ../../etc/passwd, ..\..\Windows\System32 | DENIED (403) — Working root enforced |
| Destructive Terminal | rm -rf /, mkfs, format, dd if=/dev/zero | DENIED (403) — Blacklisted binary pattern |
| Privilege Escalation | chmod 777, sudo, Set-ExecutionPolicy Bypass | DENIED (403) — Strict user privilege ceiling |
| Egress Exfiltration | Outbound DNS/HTTP requests to unverified domains | FLAGGED / QUARANTINED |
Configuration for Claude Desktop
Add Tcha as a proxy wrapper inside ~/Library/Application Support/Claude/claude_desktop_config.json (macOS) or %APPDATA%\Claude\claude_desktop_config.json (Windows):
{
"mcpServers": {
"protected-tools": {
"command": "npx",
"args": ["-y", "tcha-protection", "guard", "--mcp"]
}
}
}
Performance & Audit
- Interception Overhead: 0.42ms average.
- Output: Emits verifiable cryptographic nonces for every passed and blocked action.
- Benchmarked: 100/100 neutralization rate on the official Tcha Adversarial Test Suite.