How does ubuntu crack a password? A summary of various Linux version password cracking methods

Ubuntu Hack Password method

Power down any key (shift) to stop the Grub menu, enter advanced option for Ubuntu, and the menu that appears, move the cursor to ... (recovery mode) press E to edit, find the RO recovery nomodeset change to RW single Init=/bin/bash, and finally ctrl x reboot.

1, in the case of no login, get root permissions

If the grub password is not set, then we can use the easiest way to start the computer first, wait for the Grub menu, and if the Grub menu is hidden, press ESC to select Ubuntu, kernel 2.6.12-*-* (recovery mode), which is " Recovery Mode "Press ENTER to start it." Another option is to use the Ubuntu installation disk to obtain root privileges, use the Ubuntu installation disk to start the computer, when the "Boot:", enter "rescue"
Boot:rescue
You can get root permissions by following the on-screen prompts
Then # passwd root New password
# vi/etc/x11/gdm/gdm.conf #打开gnome的配置文件, enter in last line mode: Allowroot carriage return, find allowroot= false, change false to True, save and exit.
Then, when you reboot the system, you can log in with root. If you want to disable the root account, execute the following command:
$sudo passwd-l Root

2. Get root permissions by changing kernel boot parameters

Start the computer, wait for the Grub menu, if the Grub menu is hidden, you can press ESC, if the grub password is set, press p to unlock, for example, we chose Ubuntu, kernel 2.6.12-8-386, press E to edit the startup parameters before starting, select kernel/ boot/vmlinuz-2.6.12-8-386 root=/dev/hda2 ro Quiet Splash, press E to edit the selected Startup menu item, add RW Init=/bin/bash at the end of the parameter, and change to the following command line:
Grub edit> kernel/boot/vmlinuz-2.6.12-8-386 root=/dev/hda2 ro quiet Splash rw Init=/bin/bash
Press B to start.

3, forgot the root user/main user password

Following the first entry: in the case of no login, after obtaining root permissions, enter at the command line:
passwd root According to the prompts, input two times password can set the root user password.
To change the primary user password:
passwd System_main_username
According to the prompts, enter the password two times is OK.


Each version of Linux gets the password method:

(i) Redhat/centos/fedora system password cracking

1. Enter edit mode by E in the Grub options menu
2. Edit kernel the line last plus s (or single)
3. Press B, start to Single-user mode
4. After entering, execute the following command
# MOUNT-T proc Proc/proc
# Mount-o REMOUNT,RW/
#passwd
#sync
#reboot

(ii) Debian Linux system password cracking

1. In the Grub Options menu ' Debian gnu/linux,... (recovery mode) ', enter edit mode by E
2. Edit kernel The back of the line to the RO single init=/bin/bash, press B to perform the reboot
3. After entering, execute the following command
root@ (None) #mount-A
root@ (None) #passwdroot
root@ (None) #reboot

(iii) FREEBSD system password cracking

1. Boot into the Guide menu
2. Select each item (press 4) to enter Single-user mode
3. Enter a list of commands after entering
root@ #mount-A
root@ #fsck-y
root@ #passwd (Change Password command)
root@ #root (user name to crack password)
Enter New UNIX Password:
root@ #init6 (reboot)

(iv) Solaris system password cracking

1. Select the Solaris FAILASFE item in the GRUB option menu
2. System prompts do you wish to have it mounted read-write on/a? [Y,n,?] Select Y
3. Enter Single-user mode
4. Enter the following command: passwd
root@ #init6 (reboot)

(v) NETBSD system password cracking

1. Power on: When the prompt symbol appears and the countdown begins for five seconds, type the following directive:
> boot-s (enter single-user mode command)
2. In the following hint sign
Enter pathname of shell or return for SH:
Press Enter.
3. Type the following directive:
# mount-a
# fsck-y
4. Use passwd to change the root password.
5. Use the exit command to enter multiple-person mode.

(vi) SUSE system password cracking

1. Reboot the machine, after the Grub boot interface appears, add Init=/bin/bash to the boot Linux option, and the command line is available by passing Init=/bin/bash parameters to the kernel so that the OS runs bash before running the login program.
2. Wait a moment to appear (none) #: Command line.
3. The input mount-n/-O remount,rw means that the root file system can be reinstalled to read and write, with read and write permission to modify the password through the passwd command.
4. When you enter the passwd command, you can reset the password.
5. Remember to use mount-n/-o Remount,ro to place the root file system in the original state after the modification is complete.