recently someone has been trying to access my Steam account from somewhere in the world, always switching the location (prob. vpn). I've a pretty secure password everywhere and most are different and / or have 2FA. Now I've used Kaspersky, Windows Defender and Malwarebytes to scan my pc (Windows 10) and nothing was found. Could I somehow track anomalys in my system / determine which application is causing ONLY my steam password to leak? Literally nothing else I know of has been accessed which makes no sense as Paypal and my Bank account would be alot more valuable. I also tried changing the password to something really ridiculous and my account still got accessed the next day. (28 Digits including $4_aA- basically pretty obscure) So no way they got lucky and brute forced 3 times. (a guy was trying to tell me that my password would easily be bruteforced in less than 30 hours, I used "$uCkM41B4ll$pl34Z3!!!" as an example, as my password was similarly complex) My guess is that I somehow got malicious software that is somehow abusing a .dll that the client login window uses. I've tried changing the password on a seperate device and my network is private, meaning there are no people in this household that could somehow monitor the network and syphon out the password, which shouldn't be possible in the first place but just so you know. The steam emails are also valid, they come from the genuine steam support email, I've verified it multiple times.
Hope you can help me out as I don't want to reinstall my windows and want to learn a little about this topic.