What I see in system password cracking

Recently, some colleagues forgot the system password and were eager to use it. Instead, they turned to me to solve the problem for them. Finally, they finally solved the problem. They usually collected some information about the system password, we will present them one by one.
I. Forgot the boot password

The power-on password refers to the password that jumps out after you enable the self-check on your computer. In this case, you only need to enter the correct password and then start the system. When such a password appears, you want to enter the computer's BIOS settings are not good, so the security is relatively good.

We recommend that you do not set this type of password for your laptop. Because once you forget the password and then lose the decryption disk, you have to go to the laptop manufacturer's repair shop to burn money ).

Solution: Open the chassis andCMOS lithium battery on the motherboardThe password will disappear automatically after 5-10 minutes.

Principle: Because the boot passwordEnable BIOS settings, It will be saved inCMOS on the motherboard, The memory will disappear after a long time of power loss, so the password will disappear.

Ii. Forget BIOS password settings
The BIOS password is set by pressing the corresponding key different from the BIOS key during the boot self-check process.DELMost of the domestic products areF2)Enter the password when you set the BIOS. The boot password is also set here. This password protects the BIOS settings. The startup of the training system is not affected.
Solution: 1,Discharge through CMOSBut it is best to use debug to clear it. Because computer hardware is always broken through, it will make its service life shorter.
Another method:

After the system is started, enter the DOS environment and enter the debug command. The "-" input prompt will appear, and then enter the following command

-O 70 10

-O 71 10

-Q
If your system does not have a DOS system,We recommend that you buy a CD with a DOS system and boot it into DOS through the CD for the convenience described above,However, the premise is that the default boot sequence of BIOS is the first disk-hardware. If the boot sequence is hardware, only CMOS can be discharged.

I believe that the password can be cleared through this practice.

Principle: both the 70 and 71 numbers are used in the command line, because the data access in CMOS is achieved through the two I/O Ports 70 and 71. Port 70H is a byte address port used to set the data address in CMOS, while port 71H is used to read and write the data unit content in Port 70H setting the CMOS address.

3. Forget the logon password for Windows 98

Some employees will restrict logon by changing the Windows registry and the corresponding logon method. If the entered information is incorrect, the system will prompt the corresponding information and cannot log on. Generally, if you do not enter a password for windows network logon, you cannot use a LAN even if you log in. Solution: Press F8 to bring up the Startup menu, select safe mode (safe mode), and then enter the exercise system before self-check on the computer. Find the file with the suffix pwl and rename or delete it. Then, change the logon mode and clear the corresponding password.

Principle: A file suffixed with pwl is a password file with the file name as the login name. After deleting it, the password disappears.

4. Forget the logon password for WindowsNT/2000

To ensure the security of WindowsNT/2000, you are generally required to set up a system logon password. You cannot log on without a password.

Solution: first, we need to differentiate whether the system file format is FAT or NTFS. If NTFS is used, some boot disks cannot be used as files, because the files need to be changed or deleted. If it is FAT, you can use a general Windows 98 boot disk to start the computer, while NTFS requires other tools, such as NTFSDOS, a small software, it can be used to create two Floppy boot disks and then practice files in the NTFS file format. Boot the computer with a boot disk is now in dos state), enter the partition where the system is located, for example, drive c: if the \ windows \ system32 \ config \ sam file is renamed or deleted, you can log on with a blank password next time.

Principle: Because the c: \ windows \ system32 \ config \ sam file is equivalent to a database file in the practice system to save the password of the current system user. After deleting or changing this file, the system considers that there is no password, and a SAM file will be generated at the next startup.

 

5. Forget the Windows XP Logon password -----------------------I used the most in my daily work, because we all installed XP systems. Haha, you have to learn.

Solution 1: run the "net" command to assume that the user name with the password forgotten is xxcxz)

We know that the "net user" command is provided in Windows XP. This command can be used to add or modify user account information. The syntax format is:

Net user [UserName [Password | *] [options] [/domain]

Net user [UserName {Password | *}/add [options] [/domain]

Net user [UserName [/delete] [/domain]

1. restart the computer, press F8 immediately after the startup screen appears, and select"Secure Mode with command line".

2. At the end of the running process, the system lists the selection menus of the system Super User "administrator" and the local user "mikoo". Click "administrator" to enter the command line mode.

3. type the command "net user mikoo 123456" and change the password of the "mikoo" user to "123456 ". If you want to add a new user here, for example, the user name is abcdef and the password is 123456), type "net user abcdef 123456/add ", after adding the account, run the "net localgroup administrators abcdef/add" command to promote the user to the system management group "administrators" and grant it super permissions.

4. restart the computer and select "run in normal mode" to log on to the "mikoo" user with the changed password "123456.

At the same time, this method is also a good way to enter other people's XP systems, and do not want others to know that you enter others' computers;

Operation Method: 1.Secure Mode with command lineEnter a command similar to "net user mikoo 123456/add;

2. restart the system and create a user name MIKOO with a password of 123456. Then, you can start the system and obtain the resources you want;

3. After obtaining the information, I certainly don't want anyone to find that someone has moved his computer, so you must delete the mikoo account you have created. How can I delete it?

SimilarlySecure Mode with command line"Enter" net user mikoo/del "to delete the account, so that you do not know and obtain others' information without knowing it. Haha ~~~

 

Solution 2: Use "administrator"

We know that during Windows XP installation, the default logon is "administrator", and a new account is required to be created to log on to Windows XP, in addition, only the user account created on the logon interface of Windows XP does not display "administrator", but the "administrator" account still exists and the password is blank.

After learning about this, if you forget your logon password, press Ctrl + Alt on the logon page, and then press Del to display the classic logon screen, enter "administrator" in the user name, enter the password blank, and then modify the "zhangbp" password.

6. Forget the Linux root logon Password

Linux is another practice system that is very different from Microsoft practice system. The company's server is to apply this practice system. It has good security and its kernel is free of charge, but its practice is slightly complicated. The root Account is the default logon password for the system Administrator in Linux, which is equivalent to the Administrator in Microsft windowsNT/2K. After logging on as a root user, the system has a lot of management and practice permissions. Since the root password can be changed, other user passwords are even more "a piece of cake ". However, you must restart the computer when changing the password. You may not be able to change the password if you want to Telnet.

Solution 1: lilo

1. When lilo appears: Enter linux single

Lilo: linux single

2. After the computer is started, enter the linux Command Line.

3. # vi/etc/shadow

Delete the contents of the first line, that is, the content before "root" and "Next", in the line starting with "root,

The first line is similar

Root ::......

Save

4. # restart reboot. the root password is blank.

Solution 2: grub

1. When the grub screen appears, use the up and down keys to select the one you usually start linux (do not select dos), and then press the e key

2. Use the up and down keys again to select the one you usually start linux (similar to kernel/boot/vmlinuz-2.4.18-14 ro root = LABEL =/), and then press the e key

3. Modify the command line you see and add single. The result is as follows:

Kernel/boot/vmlinuz-2.4.18-14 single ro root = LABEL =/4. Press enter to return, and then press the B key to start, you can directly enter the linux Command Line

5. # vi/etc/shadow

Delete the contents of the first line, that is, the content before "root" and "Next", in the line starting with "root,

The first line is similar

Root ::......

Save

6. # restart reboot. the root password is blank.

Solution 3: remove the local hard disk and mount it to another linux system.

Principle: In a LINUX practice system, all types of files are stored in a fixed Directory, which is also true for UNIX.) "/" is the root directory, the system logon password is stored in the/etc directory. If the logon password is encrypted, it is stored in the shadow file; the file name is stored in the password file without encryption. It has not been used in linux for a long time. Therefore, the file name cannot be clearly remembered ). Find the user's life for password modification, and delete the password on the corresponding item because the file content is placed in a fixed format.
 

This article is from the Capricorn Ayin blog, please be sure to keep this source http://mikoo.blog.51cto.com/627637/373798