I had a fail regarding the security of my pc. I torrented a version of MATLAB from pirate bay and then tried to execute the installation script.
The script ran without asking for a password so I thought that nothing suspicious was going on. Later I saw that the installation script had written on files that a normal user didn't have write permissions on. So I am guessing my fail was that probably I have run another command which required elevated privileges earlier in the session and the shell had my root password in memory.
So my questions are,
- What are the odds that there was actually a malware there? (I know this is subjective so it doesn't matter much)
- What steps can I follow to check if I have been infiltrated?
- In order to recover from the attack I should probably do a reinstall of the OS. What should I do with the files in the home directory? As far as I understand it is possible that the virus has copied itself on them. Can I somehow check and remove it if present?
I run an ArchLinux with regular updates if this means anything.