Protecting Single user Mode

How it looks like?

How to do it?

1. Open file “/etc/rc1.d/S99single”

2. Look for line 

3. Add the following before the previous line

exec init -t1 s

exec sbin/sulogin

How to hack it?

• Using init=/bin/bash
• Mounting root partition as R/W
• Executing: 

mount -o remount,rw /

passwd

How to protect it?

• Provide encrypted password to bootloader
• Open '/etc/grub.conf'
• Add the line 

grub-md5-crypt

password --md5 'hash"

How it looks like?

How to hack it?

• Using a live CD

chroot /mnt/sysimage
vi grub.conf (remove the password line)
reboot

What to do next?

1. Encrypt HDD
2. Protect the BIOS
3. Bodyguards