My MacBook Air is being weird - solutions?

[ertyu]

Today, the finder window opened and closed without me doing anything. I thought I'd pressed something (touchpad for mouse or key combo) without noticing and moved on with my life. A little later, got up to go get water. When I put my earphones back on, a podcast on a long-burried chrome tab was playing. I did not turn it on. Nothing was playing when I left, no one was next to the laptop while I was gone, I just don't see how the podcast would have started playing.

In addition, I got an email that an old Skype account I thought lost to time had been hacked and someone had tried to buy an equador skype subscription on it. I managed to log back in, changed the password to it and the associated email account, but that's not much use if I have a keylogger I don't know of.

I canceled my card, changed the passwords to the apple accounts (where I have no payment methods saved), etc., but I still have scanned copies of documents etc. on the laptop which could probably be used to steal my identity. What fix do you guys suggest? Best I could come up with was getting an external hard drive, transferring my files, then seeing how I can restore to factory settings. How would you resolve the issue in my shoes?

Many thanks to whoever finds the time

[_bb_]

Disclaimer, this is coming from an amateur enthusiast:

Good move to change your passwords, etc. One possible solution is to download some form of anti-virus to run a scan of your system (anti-virus is the outdated term - most software is now much more advanced). Traditional anti-virus would only look at a programs hash (unique identifier) and compare it to a library of "known-bad" hash files. Basically, if it wasn't in the library it was allowed to run. The new generation of software will compare program execution and what is running in memory, using this comparison it can flag potentially suspicious behavior.

The issue with backing up your computer to a drive is that most malicious programs these days are "smart enough" to include themselves in the back up. I would look into something from Kaspersky, Panda Security, or Trend Micro - each has a personal use license, though it may cost some money, but should at least flag if there is any malicious activity. If it does, it can easily delete the program and block it from returning to your computer.

[bostonimproper]

I'd first try to diagnose whether there's network traffic you're not expecting coming in and out. You can try using something like RadioSilence to monitor. If you do have malware, I would personally do a clean OS install & reinstall apps as needed. This assumes you're already backing up most important files, etc.

[ertyu]

Thank you for the suggestions. I am not sure what traffic I am expecting and not expecting, but I appreciate the suggestion for quality tools. The internet is full of "malware scanners" targeted to noobs like me. I know enough to know many of them are scams that will land me in even worse trouble, but I don't know enough to tell the scammy from the non-scammy ones.

[slowtraveler]

Wow. I'd do a hard reset.

From here on, do all your internet activities within a sandbox, assuming your ram can handle it.

Your documents may be compromised. If you have a copy elsewhere stored before this happened, use that copy rather than the ones on your PC.