What exactly is wallet authorization? Why can a single authorization pose a long-term risk?
In the Web3 world, there’s an action that seems completely ordinary but is easy to overlook:
After connecting your wallet, click to approve the authorization request.
Maybe you just want to make a DeFi transaction, claim a reward, or use a decentralized app.
An authorization request pops up on the page. You glance at it, decide it looks normal, and click to approve it.
The transaction is complete, and your assets haven’t immediately decreased.
So you think everything is perfectly safe.
But there’s an easily overlooked issue here:
Some wallet approvals are not one-time transaction permissions; they may grant smart contracts ongoing permission to use specific assets.
If you do not understand the details of an approval, you could expose yourself to unnecessary risks for a long time.
I. What exactly is a wallet approval?
Simply put, a wallet approval allows a smart contract to perform certain actions involving your assets, subject to specific rules and permissions.
For common ERC-20 tokens, many decentralized applications require you to approve the relevant smart contract before it can transfer your tokens.
For example, suppose you plan to trade tokens on a decentralized exchange.
The platform may ask you to approve its associated contract to use a certain amount of tokens.
Once approved, a contract that meets the approval rules can call the relevant token transfer function within the scope of its permissions.
Here, it is important to distinguish between two actions:
Connecting a wallet: Allows an application to interact with your wallet, usually to read your address or request a signature.
Token approval: Allows a specified contract to use certain tokens within the approved limits.
Connecting a wallet does not usually mean you have authorized the transfer of assets.
However, if you go on to sign an approval transaction, you should carefully understand what permissions it grants.
II. Why can an approval last so long?
Many people assume that once a transaction is complete, the related approval automatically expires.
In fact, whether an approval remains valid depends on the specific approval mechanism.
For example, with the common ERC-20 allowance mechanism, an approved amount usually remains in place until it is used, changed, revoked, or otherwise altered according to the relevant contract logic.
For example:
You hold 1,000 units of a certain token.
When using an application, you approve a contract to use up to 1,000 tokens.
If that approval is still valid, it may not automatically disappear even after you stop using the application.
If your wallet later receives more of the same token, the remaining approved allowance may also be used to transfer those newly received tokens, if the specific approval rules allow it.
Of course, this does not mean that all approvals allow assets to be transferred without limit.
The actual permissions depend on the approved amount, the token contract, how the approved contract is implemented, and the security design of the relevant protocol.
But this is enough to illustrate an important point:
A transaction being complete does not mean that the permissions granted earlier have also ended.
III. Why should you pay special attention to unlimited approvals?
Some decentralized applications request large approval amounts, or even unlimited approvals.
A common reason is to reduce the need for users to approve repeatedly in the future and to lower on-chain transaction costs.
From a risk-management perspective, however, an unlimited approval means that for tokens supporting the standard ERC-20 approval mechanism, the approved contract may continue using those tokens while the approval remains valid, if other conditions allow it, without requiring you to confirm a new approval transaction each time.
Suppose you only plan to trade tokens worth 50 USDT, but you approve a contract to use an unlimited amount of that token from your wallet.
This does not mean your 50 USDT will be transferred immediately.
But if the approved contract has a vulnerability, is attacked, or is malicious, the approval could increase potential losses.
Also note that the risk of an unlimited approval does not mean unlimited losses will inevitably occur.
Actual losses still depend on the assets held in your wallet, the contract's permissions, the token's mechanics, and the conditions an attacker can exploit.
What really matters is not mistaking “convenience” for “no risk.”
IV. What situations should you watch out for?
When using Web3 applications, pay particular attention to the following situations.
First, the approval recipient does not match the application you are using.
For example, you plan to trade tokens on a platform, but the approval request that appears points to an unfamiliar contract.
Pause before proceeding and verify the identity of the approval recipient.
Second, the approval amount is clearly more than you need.
If you only need to make a small trade but are asked to approve a very large amount, check whether the application really needs that level of permission.
Third, the approval request comes from an unfamiliar link.
Phishing websites may imitate popular DeFi applications to trick users into signing malicious approvals.
Even a professionally designed page is no proof that it is genuine.
Fourth, you do not understand what you are signing.
Some operations may not appear as traditional token approval transactions and may instead involve other signing, approval, or order mechanisms.
If you cannot confirm what a signature means and what its consequences are, do not proceed just because the page says “claim for free” or “complete verification.”
Fifth, an application you no longer use still has an active approval.
An approval you granted in the past to take part in an event may still be valid after the event has ended.
So regularly checking approvals you no longer need is worth considering as part of wallet security management.
V. How can you check and manage wallet approvals?
You can follow a simple review process.
Step 1: Verify the approval recipient.
Check the address of the approved contract and, where possible, verify its identity using the project's official documentation and a trusted blockchain explorer.
Do not judge security based only on a contract's name or icon.
Step 2: Check the approval amount.
Confirm whether the approval is for a limited or unlimited amount, and decide whether it matches your current needs.
Step 3: Check the network.
Approval records may differ across blockchain networks. When checking approvals, select the correct network and corresponding token.
Step 4: Revoke approvals you no longer need.
For tokens that support the relevant approval mechanism, you can use a trusted approval management tool or interact with the relevant contract to set an unnecessary approved amount to zero.
However, revoking an approval usually requires an on-chain transaction and may incur network fees.
Before proceeding, verify the network, contract, and transaction details.
Step 5: Do not treat revoking approvals as a cure-all.
Revoking an approval only affects the corresponding permission. It cannot recover assets that have already been transferred or resolve other issues involving contracts, signatures, or wallet security.
If you suspect that you have already signed a malicious transaction, you should also review your wallet activity and take security measures appropriate to the situation.
Finally, remember:
Wallet security is not just about protecting your private keys; it is also about understanding what permissions you have granted.
Connecting a wallet is not the same as authorizing a transfer, and a successful approval does not mean the risk is limited to the present moment.
Before clicking confirm, make sure you know who the approval is for, what assets they can use, and how long the permission will last.
When you use DeFi applications, do you check approval amounts, or do you click confirm as soon as you see the button?
Feel free to share your habits in the comments.
This article is for sharing Web3 security knowledge only and does not constitute investment advice. Approval mechanisms may vary across tokens, wallets, and smart contracts. Verify the specific permissions using trusted tools.
