Ubuntu “Cheap Trick” Denial of Service
Posted February 7th, 2009 by MichaelHere’s a little something I learned the hard way today – you can’t login into Ubuntu (and presumably other Linux distros) via GDM without a correctly configured /tmp/ directory. Thus running something along the lines of:
rm -rf /tmp/will prevent anyone from logging in through GDM after a reboot. I might use this little trick in my upcoming Case Studies live fire exercise this Wednesday, but I will explain more about that in later posts.
The solution is quite simple really; first reboot your box into recovery mode and then drop into a root shell. Now run the following commands and all will be well:
rm -r /tmp/
mkdir /tmp/
chmod 1777 /tmp/
shutdown -r now