Airdrop task links are the most common phishing entry in the crypto world. A link disguised as an official announcement, click it, connect your wallet, grant an approval once, and your assets are gone. The core principle is: never trust any link, only trust the official contract address you've verified yourself in a block explorer.
Here are 3 steps to verify the contract and protect your assets before any interaction.
Step 1: Identify "Bait Replacement" — The Link Points to a Contract You Didn't Expect
The most dangerous scam isn't asking you to send coins directly, but using a "bait replacement" technique to swap the contract address. You get lured by a seemingly attractive airdrop opportunity, and the moment you click confirm, the transaction target, contract address or approval scope is secretly replaced.
What to do: Before clicking any airdrop task link, first confirm that its target contract address is official.
How to do it:
Check the domain name: The domain of the airdrop link must exactly match the project's official website. Scammers often use similar-looking characters or short-link redirects to disguise it. Paste the link into a text editor and compare character by character — don't just look at the first few letters.
Check the wallet pop-up: After connecting your wallet, don't rush to click "Confirm". Expand the signature pop-up details and look at the "To Address" and "Allowance". If the allowance shows "Unlimited" or an extremely large amount, reject it immediately.
Use transaction simulation tools: Some wallets (such as Rabby) and block explorers support transaction simulation. Run the interaction in a simulated environment first to confirm there are no anomalies in the swap target or deducted assets, then proceed in the real environment.
When to consider this step complete: You have checked the target contract address in the wallet pop-up and confirmed that it matches the address you obtained from official sources, and that the approval amount is reasonable.
Common reasons for failure: Clicking a link shared in a group chat or social media comment without independently verifying the domain and contract address. Scammers often pretend to be official support or community admins and send phishing links via direct messages.
Step 2: Verify the Official Contract on Etherscan — Your Only Trustworthy Source
Don't trust screenshots, don't trust group announcements, don't trust addresses sent via private messages. The only reliable verification method is to check it yourself on Etherscan (or the corresponding chain's block explorer).
What to do: Obtain the contract address from the project's official website or official Twitter account, then search and verify it on Etherscan/BscScan.
How to do it:
Get the official address: Only obtain the contract address from the project's official website (check the domain) and official Twitter announcements (check for the verification badge).
Check on the block explorer: Open Etherscan (Ethereum) or BscScan (BSC chain), and enter the contract address in the search box. Check the following information:
Whether the contract is Verified: A verified contract shows a green checkmark and its source code is publicly auditable. An unverified contract carries extremely high risk.
Contract name: Does it match the token name claimed by the project?
Holder distribution: Are holdings excessively concentrated in a few addresses (e.g., over 50% in the top 10 addresses)?
Transaction history: Does the address show a large volume of recent transactions?
Compare with the link you received: Compare the contract address in the link you received character by character with the official address you found on the block explorer.
When to consider this step complete: You have confirmed that the contract address required by the airdrop interaction exactly matches the official contract address (not just the first or last few characters).
Risk reminder: Scammers can create "fake tokens" with names similar to mainstream tokens and airdrop them directly into your wallet. If you try to interact with these airdrop tokens (transfer, trade, query), you may trigger a malicious contract and have your approvals stolen. If you receive unsolicited airdrop tokens, ignore them completely — do not interact.
Step 3: Limit Approval Amounts + Revoke Afterwards
Even if the contract address is correct, granting an "unlimited allowance" in one go allows that contract to drain your assets indefinitely in the future. If the contract is hacked or the project team turns malicious, your assets are fully exposed.
What to do: Set a spending cap when approving, and revoke unnecessary approvals after completing the task.
How to do it:
Case A (wallet supports custom allowance): In the wallet signature pop-up, change the approval amount from "Unlimited" to the specific amount needed for this interaction. For example, if you only need to interact with 100 USDT, approve exactly 100 USDT, not unlimited.
Case B (wallet does not support custom allowance or unlimited approval has already been given): After completing the airdrop task, immediately use a tool like RevokeCash to check and revoke the approval for that contract.
Asset isolation: Prepare a dedicated wallet for airdrop tasks, separate from the wallet holding your main assets, and do not transfer funds between the two.
When to consider this step complete: You have confirmed that the approval amount for this interaction is limited, reviewed your historical approvals on RevokeCash, and removed permissions for unnecessary contracts.
How to Confirm Correct Operation?
After completing an airdrop task, answer these three questions:
Link source: Did I get to the task from the project's official website or official Twitter, or did I click a link from a private message or group chat?
Contract verification: Did I verify the contract address on Etherscan, confirming that it is verified and the name matches the official one?
Approval status: Did I just approve a "limited allowance" or an "unlimited allowance"? If it was unlimited, have I already revoked it using RevokeCash?
If all three answers are positive, this interaction is relatively safe. If you have any doubt about any of them, it is recommended to immediately revoke the approval for that contract and transfer the main assets from that wallet to a new wallet.
