Your hardware wallet can work exactly as designed and you can still lose everything in it. All it takes is one valid signature. The device protected your keys perfectly. You just used them to hand someone permission.
That's the uncomfortable point of this Daily Crypto IQ episode. A wallet signature does not always mean "send this amount right now." Sometimes it means "let this contract move my tokens later." The button looks the same either way.
Four things that all look like "Confirm"
Wallets tend to boil very different permissions down to one familiar button: sign, confirm, approve. Underneath, you could be doing any of these:
- Signing a message. Often a login or proof that you own an address. Some messages are signed off-chain, so you pay no gas, and someone else can submit that authorization later.
- Sending a transaction. This changes blockchain state. It can move assets, interact with a contract, create an approval, or do several of those at once.
- Approving a token. This gives a spender (usually a contract) permission to move a set amount of a token from your wallet.
- Signing a permit. A signed authorization that can be submitted to the chain later, by another party.
The better question isn't "is this safe?" It's "what authority does this signature create, and for how long?"
How an approval actually works
The stream used ERC-20, the most common token standard, as the example. Other chains differ in detail but follow the same idea.
- You grant an allowance. The token contract records something like allowance(owner, spender) = amount.
- The spender pulls tokens later. It calls transferFrom(owner, recipient, amount) whenever it wants, up to that allowance.
The approval itself doesn't move anything. It creates the authority that makes a later transfer possible. So "I approved it and my wallet wasn't drained that day" proves nothing about next month.
Two more details people miss:
- Disconnecting a site from your wallet does not cancel an approval. The approval is recorded on-chain. Closing the tab is a mood, not a security measure.
- Native ETH doesn't use the ERC-20 allowance system. Wrapped ETH and other ERC-20 tokens do.
Why unlimited approvals exist (and why they hurt)
An exact approval covers only the amount needed for one interaction. An unlimited approval lets an app keep moving that token without asking again. That saves time and gas, so apps like it and users don't notice it.
The trade-off is the blast radius. If the approved contract turns malicious, gets exploited, or was fraudulent from the start, the remaining allowance is available with no further approval from you. An Ethereum security review cited on stream noted that many wallets and apps have historically defaulted to very high limits with no expiration.
An unlimited approval stays valid until it's spent, replaced, revoked, or limited by an expiring rule. Some sessions are time-boxed instead. On stream, a game approval lasted a week, from a burner wallet with little in it, which is the right way to be careless.
As of August 2026, a draft Ethereum proposal (ERC-8255, from May 2026) would make ordinary token approvals expire after a default period. It was a draft at the time, so check its status before relying on it.
Permit and Permit2: approvals without the approval transaction
- Classic ERC-20 approvals need an on-chain transaction.
- ERC-2612 ("permit") lets you change an allowance with a signed message, which another party can submit.
- Permit2, developed by Uniswap, is a shared approval system. You approve the Permit2 contract once, then sign narrower permissions for each app.
That's a smoother experience, and it makes reading the signed message critical. MetaMask specifically identifies Permit2 signatures as a target for signature phishing. Most drains today come from phishing, not hacking: you sign it yourself.
What helps: clear signing and simulation
- Clear signing means the wallet shows the request in plain language: which app, which token, which spender, how much, and when it expires.
- Transaction simulation previews what would happen: tokens leaving, unexpected approvals, suspicious contract calls. Simulations depend on assumptions about the chain's current state, and research has described malicious contracts built to fool them. Treat a clean simulation as evidence, not proof.
The pre-signing checklist
Before you approve anything, ask:
- Am I on the exact official domain? Not a sponsored search result. Drainer links often show up as paid ads.
- Am I on the right network?
- Is this a transaction, a message, an approval, a permit, or a delegation?
- Which asset is affected?
- Which contract or spender gets authority?
- Is the amount exact or unlimited?
- Does the permission expire?
- Does the request match what I thought I was doing?
- Does the simulation show anything unexpected?
- Should this be a separate burner wallet instead?
What to do after a suspicious signature
If it created a token approval:
- Stop using the site.
- Check your approvals in a trusted block explorer or an established approval-management tool.
- Revoke the suspicious allowance. Revoking changes chain state, so it's an on-chain transaction and costs gas.
- Check every network you use, and any other assets you may have approved.
If your seed phrase or private key was exposed, revoking one approval won't help. Move your assets to a new wallet with new keys. And never type a seed phrase into an approval checker or revoke site. No legitimate tool needs it. Bots are faster than you.
For the rest of the basics, see our wallet security guide and how to spot a rug pull.
FAQ
Does disconnecting my wallet from a website cancel its approval?
No. Approvals are recorded on-chain. Disconnecting only ends the site's session with your wallet. To remove an approval, revoke it with an on-chain transaction.
What is an unlimited token approval?
Permission for a contract to move any amount of a token from your wallet, without asking again. It saves time and gas, but if that contract is compromised or malicious, everything it's allowed to move is exposed.
Can a signature drain my wallet if I didn't pay gas?
It can set it up. Some signatures, like permits, are signed off-chain for free and submitted later by someone else. The signature creates the authority, and the transfer can happen afterwards.
Does revoking an approval cost gas?
Yes. Revoking changes blockchain state, so it's an on-chain transaction.
Educational content from an Underground Crypto Daily Crypto IQ livestream. Not financial or security advice for your specific setup.