How to prevent SQL injection attacks?

With the popularity of the Internet and the continuous expansion of application scenarios, we use databases more and more often in our daily lives. However, database security issues are also receiving increasing attention. Among them, SQL injection attack is a common and dangerous attack method. This article will introduce the principles, harms and how to prevent SQL injection attacks.

1. The principle of SQL injection attack

SQL injection attack generally refers to the behavior of hackers executing malicious SQL statements in applications by constructing specific malicious input. These behaviors sometimes lead to serious consequences such as data leakage, tampering, and deletion.

The principle of SQL injection attack is to take advantage of the application's lax or no filtering of user input. Hackers can perform malicious operations by injecting SQL statements into forms, URL parameters, cookies, HTTP headers, etc. Usually single quote injection, double keyword injection, joint injection, blind injection and other methods are used to attack.

2. The harm of SQL injection attacks

The harm of SQL injection attacks goes far beyond data leakage.

1. Data leakage or tampering

Hackers can see all tables, fields, and values ​​in the database and modify, delete, and add data.

2. Script injection

Some malicious programs may embed scripts in them to penetrate the system more deeply.

3. Dos attack

Hackers can use SQL injection attacks to launch Dos attacks, thereby preventing the server from functioning properly.

4. Causes user trust issues

The leakage of user privacy and financial information in the system will greatly weaken users' trust in the system and seriously affect the stability and stability of the system. safety.

3. How to prevent SQL injection attacks

1. Strict user input verification

All inputs should be specifically verified, such as filtering all sensitive characters , limit input length, etc. It is also necessary to verify the data on the back-end server.

2. Use parameterized queries

Using parameterized queries can treat user-entered data as parameters instead of inserting them directly into SQL statements, thereby reducing SQL Risk of injection attacks.

3. Principle of Least Privilege

Applications should be provided with the least privileges, rather than using a database account with all permissions. This prevents hackers from using the compromised application to conduct lateral attacks.

4. Multi-layer authentication

Enhance application security with multi-layer authentication. For example, you can use verification code, IP blacklist, access control list and other functions.

In general, the most important part of preventing SQL injection attacks is the filtering and restriction of user input. As long as you strictly control every input and deal with various attack methods, you can improve the security of the program and reduce the risk of attacks. At the same time, it is also very important to continuously improve technical awareness and learn safety knowledge.

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