The core of the principle of minimum permissions is to grant only the minimum permissions required to complete the work to balance security and efficiency. Specific applications include: 1. Assign specific permissions according to the role to avoid "all-round accounts". If developers only read and write specific tables, and only query application accounts; 2. Control the temporary permission time, use the validity function or manually record and revoke it in time; 3. In combination with the audit mechanism, enable operation logs and sensitive operation alarms; 4. Pay attention to the default permissions and view control, and use views or stored procedures to limit the data access scope.

In SQL security, the core of the Least Privilege Principle is: only the minimum permissions required for users to complete their work, no more or less . This sounds simple, but in actual operation, many people either put their permissions too loose or they are too strict to affect efficiency. The key is to find the balance point.

Let’s talk about how to apply this principle in practice from several common perspectives.

User permission allocation should be specific, don’t use “all-round account”

Many systems have a "universal account", such as using sa or root permissions to directly connect to the database. Although this is convenient, once it is leaked, the consequences will be very serious. The correct way to do it is:

• Assign permissions by role: For example, developers only need to read and write specific tables, operations and maintenance personnel need backup permissions, and application accounts only need to query permissions.
• Don't give DROP or DELETE permissions casually unless you really need it.
• When the application connects to the database, use a dedicated account instead of a shared account.

For example: a web application only needs to read user information and write logs, so it should not be able to modify order tables or delete data.

Temporary permissions must be controlled and not open for a long time

Sometimes, for debugging or going online, a user will be temporarily granted permissions. But many people forgot to take it back, which laid safety hazards. suggestion:

• Use the database's "permission validity period" feature (if supported), such as SQL Server credentials or Oracle's temporary roles.
• Record the time when manually increasing the permissions and cancel it in time after completion.
• Regularly review the permission list and clean up unnecessary permissions.

For example, if you temporarily add write permissions to the production database to the development, you should immediately restore it to read-only permission after the online launch is completed.

Permission management should be combined with audit mechanism

The principle of minimum permissions is not only allocated permissions, but also subsequent monitoring and auditing. for example:

• Turn on the audit function of SQL Server to record who performed what operations.
• Set alarms for sensitive operations (such as deletion, structural modification).
• Check the log regularly to see if there is any abnormal behavior.

To give a practical example: If you find that an application account that should only read data suddenly executes TRUNCATE TABLE , it means that permissions may be abused or the account has been stolen.

Don't ignore small details, such as default permissions and view control

Many people only focus on account permissions, but ignore the default settings of database objects. for example:

• Some databases allow public roles to access system tables by default, which needs to be checked and closed.
• Use views to limit users to only see part of the data, rather than directly opening the entire table.
• Stored procedures can encapsulate logic to prevent users from directly manipulating the underlying tables.

For example, you can create a view that only displays employee information for a certain department, and then only gives users permission to access the view, rather than the entire employee table.

Basically that's it. The minimum permissions are not done in one go, but should be continuously adjusted in accordance with business changes, so as not to save trouble or overcomplicate them.

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