In the Linux World -- Linux System Management 7

Article Title: galloping in the Linux World-Linux System Management 7. Linux is a technology channel of the IT lab in China. Includes basic categories such as desktop applications, Linux system management, kernel research, embedded systems, and open source.
　　 System Security Management
　　
Linux system security management includes multiple elements, such as general user system security, Super User System Security, file system security, process security, and network security. Only the coordination and cooperation of the above elements can ensure that the system is not easily hit by a fatal blow.
　　
　　 Objectives and elements of security management
　　
Security management goals include preventing illegal operations, preventing unauthorized persons from entering the system or unauthorized operations; data protection, prevent authorized or unauthorized users from accessing important personal information of the other party. properly manage users. A system should not be compromised by a malicious user trying to use excessive resources. Ensure system integrity, ensure the integrity of the system; keep an account, identify the user and record the operations performed by the user, and identify which operations are suspicious and which users have damaged the system based on these records, so as to take appropriate preventive measures; system protection, to prevent any user from freezing system resources, if a user occupies a certain system resource for a long time, corresponding measures must be taken to deprive the user of the right to use them; otherwise, it may affect other users and even cause system crashes.
　　
Linux system security includes three elements: physical security management, general user security management, and super user security management.
　　
1. Physical Security
　　
In general, physical security should include the following aspects:
　　
(1) Ensure the security of computer rooms, and add an alarm system when necessary. At the same time, a software backup solution should be provided to place the backed up software in another safe place.
　　
(2) ensure that all communication facilities (including wired communication lines, telephone lines, lan, and remote networks) are not monitored by illegal personnel.
　　
(3) Key or credit card identification equipment, User Password Key Distribution, file protection, backup or recovery solutions, and other key documents should be stored in a safe place.
　　
2. General user security management
　　
One of the responsibilities of the Linux system administrator is to ensure the security of user data. Part of the work is done by the user's management department. However, as a system administrator, it is the responsibility to discover and report system security issues.
　　
The system administrator can randomly select a user and send the user's security check results to him and his/her Management Department. In addition, the user's Management Department should strengthen security awareness, formulate comprehensive security management plans.
　　
3. Super User security management
　　
Super Users can read and write any files and directories in the system. Once a super user's password is lost, system maintenance is difficult and the system has no security.
　　
Important aspects of security management for Super Users include:
　　
(1) In general, it is best not to use the root account. You should use the su command to enter the common user account.
　　
(2) Super Users should not run programs of other users.
　　
(3) change the root password frequently.
　　
(4) carefully set the password validity period.
　　
(5) do not place the current working directory in front of the PATH table to avoid the intrusion of the "trov Trojan.
　　
(6) do not leave the terminal without exiting the system.
　　
(7) we recommend that you change the login name root to another name.
　　
(8) Check unusual system usage.
　　
(9) maintain the integrity of system files.
　　
(10) store the backup of the disk in a safe place.
　　
(11) ensure that all logon accounts have user passwords.
　　
(12) Start the accounting system.
　　
　　 User Password Management
　　
Computer security includes physical and logical security. By strengthening data center management, ensuring communication line security, and establishing a complete backup system, physical security is generally guaranteed. In addition, establishing and improving logical security is also an important issue, including user password management, user account management, file and directory permission management, and System Log maintenance.
　　
1. User Password Management
　　
The management of user passwords includes the set user passwords, the use of correct user password management policies, the setting of a time-effective mechanism for user passwords, and the execution of secure User Password operations.
　　
A good user password must contain at least six characters. The password should not contain personal information, such as birthday, name, and house number. It is recommended that your password contain non-letter (numbers, punctuation marks, etc.) characters, which should be easier to remember.
　　
The security of user passwords becomes weak over time. Therefore, frequent changes to user passwords are conducive to system security. The system administrator can modify the/etc/shadow file.
　　
In most cases, the loss of user passwords is related to user misoperations. Pay attention to the following points to ensure user password security:
　　
(1) do not write down the user password;
　　
(2) Users should avoid being seen by others when entering passwords;
　　
(3) ensure that the user has one password, and prevent multiple users from using the same account;
　　
(4) do not use the same password again;
　　
(5) do not use the same password on different systems;
　　
(6) do not transmit the password through the network or Modem.