A week ago, when i worked at home computer i encountered with strange issue, xorg was stuck, i tried ctrl-alt-backspace and magic keys without result, so i rebooted host.
While computer is booted i saw few errors from different daemons that they can not found some files and finally when i tried to login i got fresh login screen after entered password, again and again. Superuser was disabled, so i booted into singlemod but only one errer that i saw was ‘Unable to cd to ‘/home/ivan’ for user ‘ivan'”. Considering the suddenness of what happened, i thought that my HDD broken, i booted from livecd and checked s.m.a.r.t., hdd surface for bad blocks and did not found anything. After that my paranoia  took over and i started to search rootkits or something that can broke my OS and nothing found again.

I configured network from single mode, start xsession with browser and started searching, suddenly i found article when someone said that run install script and that script changed permissions on ‘/’, i looked at my ‘/’ and observed 0644. For me is still a mystery how it happened.