Why Unlimited Token Approvals are a Major Vulnerability
When you swap tokens on a decentralized exchange or interact with a DeFi protocol, the interface asks for permission to access your tokens. To save gas on future transactions, most dApps request 'infinite approval' (2^256 - 1). This leaves an open backdoor: if that protocol's smart contract is ever hacked, attackers can drain your tokens without needing your private key.
Hygiene Standard:
Set custom spending caps that match only the exact amount you intend to trade, rather than clicking 'Max' or unlimited approval.
How to Audit and Revoke Dangerous Approvals
Use trusted on-chain security tools to scan your public address:
- Step 1: Connect your wallet to Revoke. Cash or Etherscan’s Token Approval tool.
- Step 2: Review all active allowances across all EVM chains (Ethereum, Arbitrum, Base, Polygon, Optimism).
- Step 3: Click 'Revoke' on any dApp you no longer use regularly, or where the spending limit is set to 'Unlimited'.
- Step 4: Confirm the revocation transaction in your wallet to broadcast the updated allowance to the blockchain.
Post-Incident Wallet Isolation Protocol
If you suspect you signed a malicious phishing transaction, immediately transfer remaining unaffected assets (ETH, tokens, NFTs) to a clean, newly generated hardware wallet address, then revoke all allowances on the compromised address.