Phishing
Fake sites and messages stealing keys or approvals.
The most common way people lose crypto. Schemes: fake exchange sites (uniswop.org instead of uniswap.org), fake tech support on Discord, impersonator DMs on X, fake airdrops asking for wallet connect, fake Ledger Live 'updates'. Goal: get you to sign a tx that drains your wallet, or to type your seed phrase on a fake site. Check URLs character by character, NEVER type a seed online.
In plain words
The most common cause of losing crypto. A fake exchange site with a subtly different URL (uniswop.org instead of uniswap.org), fake support on Discord, a planted airdrop asking you to connect your wallet. You click 'sign' and your wallet is empty. Check URLs character by character, NEVER type a seed phrase online anywhere, don't trust DMs.
Example
Sept 2024: fake 'Solflare support' DMs on Discord drained $1.2M from SOL wallets.