SQL injection attack is a common means of network attack. Attackers use this method to obtain sensitive data or destroy the database by sending malicious SQL code to the Web application server.

The principle of SQL injection attack, in Web applications, the data input by users is usually passed to the background program for processing and storage. If the program does not correctly filter and verify the data input by the user, then the attacker can pass the data containing malicious SQL code to the background program, thus realizing the SQL injection attack.

SQL injection attack is very harmful, it can make the attacker obtain sensitive information in the database, including account number, password, credit card information, etc., causing huge losses to individuals and enterprises. In addition, attackers can also destroy the database through SQL injection attacks, such as deleting data and tampering with data, which has a serious impact on system operation and business.

Measures to prevent SQL injection attack:

1. Filtering and verifying user input: Web applications should filter and verify the data input by users to ensure that the input data meets the specifications and requirements, thus avoiding SQL injection attacks.

2. Use parameterized query: When writing code, you should use parameterized query instead of splicing strings to avoid malicious SQL code being inserted into query statements.

3. Minimize permissions: reduce the permissions of database users as much as possible, and only provide necessary database access permissions to avoid the threat of one user to other users.

4. Install the security update patch: Install the security update patch of the database software in time to ensure that the database system is in the latest security state.

5. Restrict error information: When an error occurs, the disclosure of error information should be restricted to prevent attackers from obtaining sensitive information from the error information, such as database login names and passwords.

6. Enable auditing and logging: Enabling auditing and logging helps to monitor and identify SQL injection attacks, and find and handle abnormal situations in time.