Linux password protection

Before writing the method of Linux password cracking, although it is very convenient to forget the password, but at the same time others can easily crack your liunx virtual machine, security problems exist.

Here are some security protections for liunx passwords:

1. Prevent the root password from being cracked (set boot password)

Prior to understand the way to crack the root password, in fact, is to enter the single user mode boot to modify the root password, then as long as the boot set a password, the other people can not casually enter your boot entry, modify your password.

How to set the password for boot:

(1) in CentOS6.5, right-click on the desktop, click "Open in Terminal", enter "gedit/etc/grub.conf" after the return, open the boot configuration file

　　

(2) In the popup window, set the password for boot, add a line "password=123456" (password optional)

　　

(3) Restart the system, enter the boot menu, found at this time can not press "E" to operate, you need to press "P" to enter the boot password

　　

(4) Enter the previously set password 123456, then return

　　

(5) It is now possible to continue the operation.

　　

2. Break boot password (boot from CD)

Although we have set a password for the boot boot entry, don't assume that your virtual machine is safe at this point because there is also a way to crack the boot password. Or, what should you do when you forget the boot password?

To start cracking the boot password from the CD:

(1) Right-click centos6.5--Power Supply--enter firmware when power is turned on

　　

(2) using the arrow keys to move the cursor to the "Boot" tab, use "+" key to the "CD-ROM drive" to the first line (the disc is set as the first boot item), and then press "F10" to save and exit

　　

(3) Select the third item "Rescue Installed System"

　　

(4) always select "OK" and enter until the shell is set

　　

　　

　　

　　

　　

　　

　　

　　

(5) After entering the shell settings, enter "Cd/mnt/sysimage", then "VI/etc/grub.conf", you can see the Set boot password now

　　

(6) Finally, start the CD drive to the third line

3. Prevent the boot password from being cracked (encrypt bios)

As the saying goes, he has a good count, I have a wall ladder. To prevent someone from cracking your boot password, you can encrypt the BIOS

Also need to "turn on the power supply to enter the firmware", select "Security", enter the set password, so enter the BIOS requires a password

　　

　　

　　

However, in fact, even if this, meet the real computer master, still can crack your password ...

Linux password protection