Wallet Drainer Approvals – What You’re Actually Signing When You Connect Your Wallet
“Just connect your wallet to check your eligibility.”
That phrase – or some variation of it – appears on every fake airdrop site, every honeypot token page, and every malicious DeFi protocol we have documented on this site. It sounds routine. It is not.
When you connect your wallet and sign a transaction on a malicious site, you are not just logging in. Depending on what you sign, you may be granting that site’s smart contract permanent permission to transfer every token in your wallet – instantly, automatically, and irreversibly.
This guide explains exactly what happens at a technical level, in plain English, so you understand what you are agreeing to before you sign anything.
Two Different Actions – Connect and Approve
The first thing to understand is that “connecting your wallet” and “signing an approval” are two completely different actions with completely different consequences.
Connecting your wallet is genuinely low-risk. When you click “Connect Wallet” and your MetaMask or Phantom popup appears, you are giving the site permission to read your wallet address and token balances. Nothing can be moved. No funds are at risk. This is equivalent to showing someone your bank account number – they can see the balance but cannot access the funds.
Signing a token approval is where the risk begins. A token approval is a transaction that grants a smart contract permission to move a specific token from your wallet, up to a specified amount, at any time in the future – without requiring your signature each time.
Legitimate DeFi protocols use approvals all the time. When you swap tokens on Uniswap, you first approve Uniswap’s contract to access your tokens. When you deposit into a lending protocol, you approve that protocol’s contract. This is normal DeFi mechanics.
Malicious sites exploit the same mechanism. The difference is in what you are approving and for how much.
The Unlimited Approval Problem
When a legitimate protocol asks for a token approval, the responsible ones ask for exactly the amount needed for your transaction – no more. Many DeFi interfaces, however, default to requesting “unlimited” approval – meaning the contract can move as many tokens as you hold, as many times as it wants, forever, without asking again.
This is where wallet drainers operate.
A wallet drainer is a smart contract specifically designed to request unlimited token approvals from as many wallets as possible, then execute mass transfers of those tokens to the attacker’s wallet. The contract does nothing visible when you sign the approval. It waits. Then at a time of the attacker’s choosing – sometimes minutes later, sometimes days – it drains every approved token in a single transaction.
You will not see it happen in real time. You will check your wallet later and your tokens will be gone.
What a Malicious Approval Actually Looks Like
When MetaMask or another wallet shows you a transaction to sign, it displays the details of what you are approving. Most people click through without reading. Here is what to look for:
The spender address – this is the smart contract you are granting permission to. Before signing any approval, check this address on Etherscan. Is it verified? Does it have a legitimate history? An unverified contract with no transaction history is a red flag.
The amount – legitimate approvals for a specific transaction will show the exact amount needed. An approval requesting “unlimited” or a astronomically large number (like 115792089237316195423570985008687907853269984665640564039457584007913129639935 – the maximum uint256 value) for a simple claim or check is a drainer request.
The token – which token is being approved? Some drainers target your most valuable holdings specifically. Others approve multiple tokens in sequence.
The gas fee – approvals cost a small amount of gas. If a site is asking you to sign something for “free” that requires gas, you are paying to give someone access to your wallet.
How Drainers Are Deployed
Understanding how wallet drainers reach victims helps you recognize the pattern before you interact.
Fake airdrop sites – as documented in our Flare XRP airdrop article, malicious sites are built to look like legitimate project announcements. Every link on these sites routes to a wallet approval prompt.
Compromised Discord and Telegram links – attackers gain access to legitimate project community channels and post malicious links disguised as official announcements. The link leads to a drainer site that looks identical to the real protocol.
Search engine ads – attackers purchase Google ads for terms like “Uniswap”, “MetaMask download”, or “Coinbase Wallet”. The ad leads to a pixel-perfect copy of the real site with a malicious contract underneath.
NFT and token claims – unexpected tokens appearing in your wallet sometimes carry malicious approval requests embedded in their claim process. Interacting with these tokens – even attempting to sell them – can trigger an approval you did not intend to sign.
The Permit Signature – The Most Dangerous Evolution
Standard token approvals appear as transactions and cost gas – giving you a moment to review what you are signing. The Permit signature is more dangerous because it does not appear as a transaction at all.
EIP-2612 introduced a standard called Permit that allows token approvals to be signed as messages rather than transactions. Message signatures are free, instant, and do not show up on the blockchain until they are used. They look like a simple “sign this message” popup rather than a transaction review.
A wallet drainer using Permit signatures shows you what appears to be a harmless message signing request. You sign it, nothing visible happens, no transaction appears on chain. Then the attacker submits the signed permit to the contract and drains your tokens in a single transaction – all in one step, with your signature already obtained.
This is why “just signing a message” is not safe on malicious sites. Message signatures can carry the same permissions as transaction approvals.
How to Check What You Have Already Approved
If you have been using DeFi for any length of time, you almost certainly have outstanding token approvals you have forgotten about. This is normal – and manageable.
Revoke.cash is the standard tool for reviewing and revoking token approvals. Connect your wallet, and it shows every approval you have ever granted – which contract, which token, what amount. You can revoke any approval with one click.
Etherscan Token Approval Checker – etherscan.io/tokenapprovalchecker – similar functionality for Ethereum and EVM chains.
What to do when you find suspicious approvals:
- Revoke any approval for a contract you do not recognize
- Revoke any unlimited approvals for contracts you no longer actively use
- Revoke anything granted to an unverified contract address
Revoking costs a small gas fee but is always worth doing for suspicious or unused approvals.
Best Practices Going Forward
Before signing any approval:
- Read what the popup says – token, amount, spender address
- Check the spender address on Etherscan – is it verified? Does it match the protocol you think you are using?
- If the amount is “unlimited” and you are not certain why, reject it and look for a way to approve only the amount needed
- Verify you are on the correct URL – malicious sites use domains that look almost identical to real ones
General wallet hygiene:
- Keep your main holdings in a hardware wallet – Ledger or Trezor. Hardware wallets require physical confirmation for every transaction, making remote draining essentially impossible
- Use a separate “hot wallet” with minimal funds for DeFi interactions – if it gets drained, the damage is contained
- Review your approvals on revoke.cash monthly and revoke anything you no longer use
Never:
- Sign an approval on a site you reached through a link in a DM, email, or social media post without verifying the URL independently
- Sign anything on a site that appeared in a search engine ad rather than organic results
- Assume “just signing a message” is safe – Permit signatures carry real permissions
What To Do If You Have Been Drained
Act immediately – every second matters as attackers move funds quickly.
- Do not try to “save” remaining tokens by moving them yourself – the drainer contract may have approvals for multiple tokens and can front-run your transactions
- Transfer remaining assets to a completely fresh wallet – one that has never been connected to any site
- Revoke all approvals on the compromised wallet at revoke.cash – even after draining, the contract may retain permissions for tokens it missed
- Report to the relevant chain’s community channels – Ethereum, Solana, and other chains have community fraud reporting resources
- Report to the FBI at ic3.gov and the FTC at reportfraud.ftc.gov
- Treat the compromised wallet as permanently burned – do not continue using it as a primary wallet even after revoking approvals
Crypto transactions are irreversible. Drained funds are almost never recovered. The realistic goal after a draining event is containment – protecting what remains and preventing future exposure.
The One Defense That Changes Everything
Every defensive measure in this guide reduces your risk. One changes the equation entirely.
A hardware wallet keeps your private keys completely offline. Signing any transaction – including malicious approvals – requires physical confirmation on the device itself. A remote attacker cannot drain a hardware wallet because they cannot physically press the confirm button.
Hardware wallets are not impenetrable – social engineering can still trick you into confirming a malicious transaction on the device. But they eliminate the entire category of remote, automated draining that this article describes.
If you are holding any meaningful amount of crypto, a hardware wallet is the single highest-impact security purchase you can make.
👉 Ledger – receive $10-30 in BTC with your first purchase through our link 👉 Trezor – open source hardware wallet, strong community track record
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