What is an Approve?
Approve is to allow another account (It can be an ordinary personal account or a contract account), which can control your asset without your permission. Approve is a very dangerous action.
Approve widely exists in ETH, TRON and all EVM compatible public chain
Approve is like pre-authorized debit in Paypal, it allows dapp finish a set of operations automatically and save cost. Ex, it is heavily used in Uniswap/Opensea, etc.
Approve is a 0 amount transaction, and you need to pay attention to all transaction confirmation window
Malicious dapp will leverage different ways to get your approve and transfer all your assets
How to prevent
1 Don’t play DApps from unknown sources,
2 Regularly use
to cancel the approval
Let’s use Etherscan (https://etherscan.io/tokenapprovalchecker) to revoke an NFT approval as an example:
1 Click ‘Connect to Web3’ and connect your MathWallet
2 Switch to ERC-721 tab
3 If you do not know the source of the Approved Spender (such as Opensea, Looksrare), please click the ‘Revoke’ button and submit the revoke transaction.