http://secure45nbquibuw6thmenrfamhobdkkrllgxrtayn4sgmnexremexyd.onion/guides/linux-hardening.html
Edit /etc/pam.d/passwd and add the rounds option. For example: password required pam_unix.so sha512 shadow nullok rounds=65536 This makes shadow perform 65536 rounds. Your passwords are not automatically rehashed after applying this setting so you need to reset the password with: passwd $username 8.6 Restricting Xorg root access Certain distributions run Xorg as the root user by default.