T09 · Insecure Skill Coding Practices
- Location
scriptsmain.py:7- Finding
Unsafe Construction and Broadcasting of Wallet-Signed Transactions
- Content
View full analysis
Vulnerability Details
File Location:
scriptsmain.py, lines 7-9 and 27-40
Vulnerability Type: Unsafe blockchain transaction signing and broadcasting
Risk Level: HighVulnerable Code
python PRIVATE_KEY = os.getenv("PRIVATE_KEY") ACCOUNT = w3.eth.account.from_key(PRIVATE_KEY)python def deploy_to_zora(image_path, name, symbol): """Deploys a basic ERC721 to Zora Network.""" # Simplified Zora Minting Logic # 1. Upload image_path to IPFS (using a service like Pinata or Zora API) ipfs_link = "ipfs://..." # 2. Build Transaction for Zora 721 Factory # (Simplified for example) tx = { 'from': ACCOUNT.address, 'nonce': w3.eth.get_transaction_count(ACCOUNT.address), 'gas': 2000000, 'maxFeePerGas': w3.to_wei('2', 'gwei'), 'maxPriorityFeePerGas': w3.to_wei('1', 'gwei'), 'data': '0x...' # Zora Contract Creation Bytecode } signed_tx = w3.eth.account.sign_transaction(tx, PRIVATE_KEY) tx_hash = w3.eth.send_raw_transaction(signed_tx.rawTransaction) return w3.to_hex(tx_hash)Technical Analysis
The module reads a wallet private key and derives the signing account during import. The deployment function then signs and broadcasts a transaction without validating critical transaction properties.
The transaction has no verified Zora factory contract address, explicit chain ID, valid audited deployment bytecode, gas estimation, or confirmation step. Its
datafield contains the placeholder value0x..., which is not valid contract creation bytecode. The hardcoded gas and fee limits are also not checked against current network conditions.Because no
toaddress is supplied, the transaction is treated as contract creation rather than a call to a documented Zora factory. As currently written, the placeholder data will ordinarily cause transaction construction or submission to fail. If the ...[truncated 1818 chars]- Remediation
View remediation
Remediation Suggestions
- Do not initialize the signing account at module import. Load the key only inside a narrowly scoped signing component when a transaction is ready for authorization.
- Verify that
ZORA_RPC_URLreports the expected Zora chain ID before constructing or signing any transaction. - Use the official, audited Zora factory contract address and ABI rather than raw placeholder deployment bytecode.
- Add an explicit
chainIdand validate the destination address, calldata, value, nonce, fee limits, and expected contract operation. - Generate calldata through the contract ABI and ensure the collection name, symbol, and metadata URI are encoded as expected.
- Estimate gas through the RPC and apply a bounded safety margin instead of using a fixed gas limit.
- Simulate the transaction and reject reverts or unexpected state changes before signing.
- Present the destination, chain, maximum fee, value, and decoded operation for explicit operator confirmation.
- Use a dedicated low-value deployment wallet or external signer rather than a general-purpose private key.
- Fail closed when required environment variables are absent, malformed, or inconsistent.
