I will write a bit about stealers and malware in general so that users understand what they need to protect themselves against. There are 2 popular types of malware: the rat and the stealers (there are also ransomware, hvnc etc., but they are less popular, so I will not discuss them now).
1. The stealers masquerades as an executable, .exe, .msi, etc. (again, there are exploits for .pptx or .docx, but they are very rare and used for pinpoint infections), after running the file it collects data (browser cookies, passwords, crypto wallets, ftp, autocomplete, desktop files, maybe something else, but this functionality is present in any stealers), and after collecting the program is removed.
What can I do to avoid running into a stealers? You can use antivirus, but even the best antivirus won't save you from all malware. It's better to use your head, just don't download executables from unverified sources, but sometimes you have to do it, so I use a remote server to run them (they cost about $20-50 a month, but it will save you from losing hundreds and thousands of dollars).
What should I do if you are already infected with stealer? The most important thing is to change your password on your mail (It is best to use google mail with 2fa enabled, since it will only be accessible via cookies, which will not be valid if you change your password) Once you have access to your mail, start changing passwords to all important services. Since this is a forum for webmasters, it is important to check your sites, and more specifically, the pages created when you lost access. As an example, this site was hacked and stealers began to be distributed through it ( http://pdc.cl/temp_54hdi5s/divyxolimijuce/64733-download-photoshop-crack-full.html main domain http://www.pdc.cl/ ). You can also reinstall your system, stealer although it is removed, but before it is removed it may download other malware such as miners or clippers, so reinstalling your system would be a good choice.
2. Rat. This is a more complex program, it is distributed as an executable file, but it does not steal data from your PC, it creates remote access to it. Through Rat, an intruder can control your computer, watch what's happening on your screen and through your webcam, and do many other bad things. The only solution is to completely reinstall the system.
I don't know English very well, so this text was translated through a translator, I hope you understood the main point and it helped you