A .grub menu login control
In the Internet environment, most servers are managed by way of remote login, and the local guide and terminal login process tends to be neglected, leaving a security risk. Especially when a lack of server room environment where strict, safe systems of control, how to prevent other users from unauthorized intervention became necessary attention. 
Let's press the ESC directly into the grub menu changes very safe, and that we want to set a username and password only aware of these changes can go
1. To back up we do to prevent failed
2. to set user profile and password
3. rebuild grub menu
4. Verify that it is valid
II. Detection weak passwords
In the Internet environment, too simple password is the biggest risk facing the server. Although we all know that setting
a longer, more complex passwords are more secure, but there will always be some users because the sake of convenience and simple, easy to remember the
password string. For any administrator bear responsibility for security in a timely manner to identify these weak password account is necessary,
it is easy to take further security measures (such as remind users to reset passwords more secure).
John the Ripper password cracker is an open source tool that can quickly analyze Ming in the case of a known ciphertext
password string text, supports DES, MD5 and other encryption algorithms, and allows the use of a password dictionary (including various password group
together a list of files) to brute force. By using John the Ripper, can be detected Linux / UNIX system
password strength user account.
1. Download and install John the Ripper
2. We make it into a script file
3. Compile
4. By analyzing our dictionary user account and password
