T09 · Insecure Skill Coding Practices
Error
- Location
- scriptsmain.py:7
- Finding
- Unsafe Construction and Broadcasting of Wallet-Signed Transactions## Vulnerability Details **File Location**: `scriptsmain.py`, lines 7-9 and 27-40 **Vulnerability Type**: Unsafe blockchain transaction signing and broadcasting **Risk Level**: High ### Vulnerable 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 `data` field contains the placeholder value `0x...`, which is not valid contract creation bytecode. The hardcoded gas and fee limits are also not checked against current network conditions. Because no `to` address 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
- ## Remediation Suggestions 1. 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. 2. Verify that `ZORA_RPC_URL` reports the expected Zora chain ID before constructing or signing any transaction. 3. Use the official, audited Zora factory contract address and ABI rather than raw placeholder deployment bytecode. 4. Add an explicit `chainId` and validate the destination address, calldata, value, nonce, fee limits, and expected contract operation. 5. Generate calldata through the contract ABI and ensure the collection name, symbol, and metadata URI are encoded as expected. 6. Estimate gas through the RPC and apply a bounded safety margin instead of using a fixed gas limit. 7. Simulate the transaction and reject reverts or unexpected state changes before signing. 8. Present the destination, chain, maximum fee, value, and decoded operation for explicit operator confirmation. 9. Use a dedicated low-value deployment wallet or external signer rather than a general-purpose private key. 10. Fail closed when required environment variables are absent, malformed, or inconsistent.