Full disclosure, my seed was stored in a text file on a networked drive. However, my wallet was password protected.
I know that I should not have stored my seed digitally but how is this breach likely to have occurred and how best to prevent it happening again?
Thanks
It seems to me that this is the main cause why you lost your coins, seed is all that's needed for someone to access your coins. In your case probably your PC was infected with some type of
RAT. The fact that you did not see any balance in your old 2.9.3 wallet since such old wallets have known problems with sync, only delayed the actual moment when you found out that your balance is 0, and this is after update to latest version.
How to prevent such a thing from happening again? You have to start thinking and acting in another way, you are your own bank and you need best possible protection. A few tips for the start :
- format your hard drive (make backup of important things) and install clean OS.
- start using top security software (antivirus, firewall, antimalware).
- regularly update your OS with critical and security updates.
- stop using desktop/online wallets and switch to to hardware wallet.
- pay attention to what you download from internet.
Virus scans are worthless. They only check for signatures and maybe some behavior analysis.
Anyone who has invested more than a few hours into reading how AV's work, knows how to code malware which will not be recognized as such by an AV.
I agree with your statement, but only if AV is not updated with latest definition and if such AV not use behavioral analysis. In case something is suspicious good AV will put such file in quarantine or delete it. I personally tested a few fake Electrum wallets, every attempt to download them is stopped even before download actually began.
According to your statement AV is actually useless, if it takes only few hours to code malware which would infected any computer, then almost every device which would come into contact with such malware should be infected regardless of the protection it possesses.