So I'm still new to GNU/Linux: recently I installed Debian 9.1 with KDE. Now after executing:
stat --format '%a' /etc/sudoers
I found out that my sudoers file has the
640 permissions instead
0440 set. I changed this by running
pkexec chmod 0440 /etc/sudoers and inspected the file's contents which seem to be fine.
Now I'd like to know what could have caused these permissions to change and how problematic that is. I only read that this is a security risk.
And what does it mean: does that happen often? How to best prevent these permissions from changing? Continous monitoring of the file's permissions with immediate warnings of any change maybe? Is there a tool for this?
I'm not sure whether this question would be more appropriate here or at the Unix & Linux Stack Exchange. I'm more interested in the security-implications.