Quote from: LFC_Bitcoin on March 09, 2020, 07:41:32 PM

If person X used a laptop that held some of their bitcoins over public WIFI is there any chance at all that somebody could for example steal their wallet.dat &/or see what their wallet password is.

It depends on the rest of your security set up and what kind of wallet you are using, but there are other risks too.

An attacker can use an unsecured WiFi network to spy on the data you send across it. This could include usernames and passwords if they aren't otherwise encrypted, and they could use this to access web wallets or exchange accounts. An attacker can use a WiFi network to distribute malware. This could be in the form of a keylogger to record your login details to a web wallet, could be clipboard malware to change the address you have copy and pasted, could be designed to send your wallet.dat to them, or could be to change the destination of any transaction you try to sign.

Even if you are using a hardware wallet you are not completely safe. Although you wouldn't be susceptible to any of the attacks above (provided you double check what shows up on the screen of your hardware wallet), it is conceivable that an attacker could set up a man in the middle attack, and change a bitcoin address which is being displayed to you. For example, if you were connecting to a service to deposit some bitcoin, the receiving address of the service could be changed to the address of the attacker before you even see it. So even if you confirm everything is correct on the screen of your hardware wallet, you are only confirming against an already altered address.

I would recommend never using public WiFi for anything truly sensitive or valuable, and never log in to any accounts via one. If I ever do have to use one, I use a Live OS which is wiped afterwards and Tor with HTTPS.