Wallet drainer
In short A wallet drainer is malicious code, usually behind a fake site, that tricks you into signing transactions or approvals that empty your wallet.
A wallet drainer is a scam toolkit that steals crypto by getting the victim to sign something. It does not break your wallet's encryption or guess your seed phrase. Instead, it presents a request that looks routine, such as connecting to claim an airdrop or mint an NFT, and the signature you approve hands control of your assets to the attacker.
Most drainers run on a cloned or fake website promoted through hacked social accounts, fake airdrop announcements, sponsored search results, or direct messages. When you connect, the script reads your balances and asks for the most valuable permission it can get. On EVM chains that is often an unlimited token approval, a Permit or Permit2 signature that authorizes transfers without an onchain approval step, or an NFT setApprovalForAll. On Solana it is usually a transaction that transfers tokens or reassigns account ownership. Many drainers are sold as a service, with the developer taking a cut of each theft.
For anyone active with small tokens, this is one of the most common ways to lose funds. Signatures happen in seconds, the attacker's wallet sweeps assets almost immediately, and onchain transfers cannot be reversed. A permission granted today can also be used later, so the loss does not always happen at the moment you sign.
Treat every link from a DM, reply, or unexpected announcement as suspect, and reach sites through bookmarks. Read what your wallet says you are signing; if it is an approval or a signature you cannot interpret, reject it. Use a separate wallet with little in it for new sites, and review and revoke old approvals regularly with a token approval checker.