I want to make Linux my main OS. I've used Windows for decades. Since Vista or 7, the Windows security model is this, from what I understand:
- unprivileged programs have limited/no ability to do scary things to your computer. they might be able to read some data, but it's not going to implant malware in the boot sequence for Windows.
- if a program wants escalation, it triggers a UAC popup and the user has to accept it. Remote programs cannot accept UAC on a physical person's behalf. Escalated programs have admin level control and can do the scary things.
- As with any OS, there may be privilege escalation vulnerabilities that escalate (1) into (2).
I've only had Windows malware a few times since Win7, and the entry point was fairly avoidable. (Running a sketchy EXE, and a possible drive-by malware install via an advertisement. I could never prove the latter.)
I have never run a password on my Windows machines.
On any system, physical access is game over.
On Linux, the password is paramount. I've tried to understand the security model and I keep failing. Synthesizing from arch wiki
SSH
Equivalent to local physical access as the user. If it's a sudoers or root account, it can do scary things. Not a threat if ssh is disabled or well secured (password or key pairs).
If a network has a well configured firewall (on the router), it should block ssh requests from outside the network unless the admin specifically wants SSH outside the network.
As with any OS, there may be bugs that allow remote access outside of SSH.
Local login / password prompts to physical users
Without a password, you can't escalate to root and install new software. Some software, often dealing with hardware (smartctl) requires sudo/root to run.
Encrypted drives
Passwords can decrypt drives if they are encrypted.
Keyrings
Some DEs (KDE) offer a 'keyring' that stores passwords. It's locked/encrypted with a password, usually the same as the login password.
So what am I missing? Is Windows + UAC + no password secure? What is Linux protecting us from by using passwords?