The way they usually work is they give you some string and you sign it to prove you own the address.
Could a malicious air drop make a transaction sending all your BTC to them, and then you sign it, and then they broadcast it to the network?
Or is signing a message different than signing a transaction?
since i know airdrop until now i still find some airdrops that can give coins / tokens for free without having to sign any message .. we only do some conditions like share/like or subscribe via social media .. after that we are waiting for distribution ... but if anyone asks something from us in any form then you should leave the airdrop because it could endanger yourself