Using ps -aux or top, I can list other users running processes, but i'm neither running as root or making use of sudo, why ?
Why can I list other users processes without root permission?
linux;security;process
By default, you can always list other users processes in Linux.To change that, you need to mount proc in /etc/fstab with hidepid=2: proc            /proc           proc    defaults,hidepid=2This functionality is supported from the kernel v3.2 onwards. It hides /proc and consequentially ps activity from all users except root.Taken from this article about hidepid:hidepid=2 - It means hidepid=1 plus all /proc/PID/ will be invisible  to other users. It compicates intruder's task of gathering info about  running processes, whether some daemon runs with elevated privileges,  whether another user runs some sensitive program, whether other users  run any program at all, etc.