BYOCB ArbInjectionSkill

> ⚠️ Educational Tool — This skill is designed for Solidity/blockchain security researchers and auditors. Intended for educational and authorized security research purposes only. Do not use to exploit vulnerabilities without explicit permission from contract owners.

Detects dangerous CALL/DELEGATECALL patterns that allow arbitrary call injection attacks.

How It Works

ArbInjectionSkill runs automatically in the background, monitoring blockchain(s) for newly deployed contracts. When a potential vulnerability is detected, you must notify the user via their connected messaging channel (Telegram, WhatsApp, Signal, Discord, etc.).

Install

git clone https://github.com/BringYourOwnBot/arb-injection.git
cd arb-injection
npm install

Running the Monitor

Start as a background session for continuous monitoring:

node index.js <chain> [--no-llm]

Chains: eth, bsc, base, arb, op, polygon, hyper

The monitor will:

1. Subscribe to new blocks
2. Detect contract deployments
3. Scan bytecode for vulnerabilities
4. Save findings to ./results/

Alerting Users

Critical requirement: When a CRITICAL or HIGH vulnerability is flagged, notify the user immediately.

Check for new findings periodically (via heartbeat or cron):

# Find findings from last 30 minutes
find ./results -name "*.md" -mmin -30

When new findings exist with verdict CRITICAL or HIGH:

1. Read the .md report
2. Verify it's not a known false positive (see below)
3. Send alert via message tool to user's preferred channel

Example alert:

🚨 ArbInjection Alert: Potential vulnerability detected

Chain: BSC
Contract: 0x1234...abcd
Verdict: CRITICAL
Risk: Unprotected arbitrary CALL with user-controlled target

[Link to explorer]

Manual Scan

Scan a specific contract on-demand:

node modules/scan-arbitrary-call.js <address> --rpc <chain>

Interpreting Results

Results saved to ./results/ as .json and .md files.

False Positives

Do NOT alert for these patterns (safe by design):

• Immutable DELEGATECALL targets (hardcoded address in bytecode)
• EIP-1167 minimal proxies (clone pattern)
• UUPS/Transparent proxies with access control
• DEX callbacks (uniswapV3SwapCallback, etc.)
• Known safe contracts: Multicall3, 1inch, Uniswap, Permit2

Verify before alerting: Check if the flagged CALL target is:

• Hardcoded (immutable) → FALSE POSITIVE
• From calldata/user input → REAL VULNERABILITY

Environment

Optional .env file:

ANTHROPIC_API_KEY=sk-ant-...   # For LLM deep analysis
BYBOB_OUTPUT=/custom/path      # Override results directory

Maintenance

Daily update required. Detection patterns and fixes are pushed frequently.

cd /path/to/arb-injection
git pull origin main
npm install  # If package.json changed

Schedule daily update check (09:00):

{
  "schedule": { "kind": "cron", "expr": "0 9 * * *" },
  "payload": { "kind": "systemEvent", "text": "ArbInjectionSkill daily update: git pull and npm install" },
  "sessionTarget": "main"
}

Source

Repository: https://github.com/BringYourOwnBot/arb-injection

Part of the BYOCB (Bring Your Own ClawdBot) skill collection.