Wallet drainer

A wallet drainer is a malicious website or script that tricks a user into signing approvals or transactions that let an attacker move the tokens and NFTs out of their wallet. Trust Wallet's explainer says drainers target the permissions you grant to dapps or the transactions you sign, usually reached through phishing links or fraudulent dapps made to look like trusted ones, and that once an approval is given the attacker can move assets without further consent. Revoke.cash separates three patterns: a token approval or gasless Permit signature to a malicious contract, a marketplace signature that lets the attacker "buy" approved assets for nothing, and a stolen seed phrase.

Fake airdrops are a common delivery route. ethereum.org describes the flow: a scam token appears in your wallet, a site invites you to claim it, and the claim asks you to approve a transaction. Revoking a malicious token approval stops further theft through it, but for marketplace signatures revoke.cash says that once assets are stolen there is no way to get them back. See airdrop scams.