How to prevent SQL injection attacks in PHP language development?

In the process of website development, SQL injection attack is a common security vulnerability, which allows attackers to obtain sensitive data of the website or control the website by maliciously injecting SQL code. PHP is a commonly used back-end language. The following will introduce how to prevent SQL injection attacks in PHP language development.

1. Using parameterized query
   Parameterized query is a SQL statement that uses placeholders. The data is separated from the placeholders through the pre-compilation stage, which improves the security of the SQL statement. In PHP, you can use the prepared statements provided by the PDO (PHP Data Objects) extension to implement parameterized queries. For example:

// 创建PDO对象
$pdo = new PDO("mysql:host=localhost;dbname=test", "root", "password");

// 创建预处理语句对象
$stmt = $pdo->prepare("SELECT * FROM users WHERE username = :username AND password = :password");

// 绑定参数
$username = $_POST['username'];
$password = $_POST['password'];
$stmt->bindParam(":username", $username);
$stmt->bindParam(":password", $password);

// 执行语句
$stmt->execute();

Through placeholders and binding parameters, security issues caused by SQL injection attacks can be avoided.

2. Filtering and escaping input data
   When processing user input data, the data should be filtered and escaped to avoid malicious script or code injection. In PHP, you can use built-in functions for data filtering and escaping. For example:

// 过滤输入的字符串
$username = filter_var($_POST['username'], FILTER_SANITIZE_STRING);

// 转义输入的字符串
$username = mysqli_real_escape_string($connection, $_POST['username']);

Among them, the FILTER_SANITIZE_STRING function will filter labels and special characters in the string, while the mysqli_real_escape_string function will filter the special characters in the input data escape.

3. Verify input data
   Verifying input data is a very important step to avoid attacks by malicious users, such as entering illegal characters, input length exceeding the limit, etc. In PHP, you can use regular expressions and filter functions to verify input data, for example:

// 验证邮箱地址
if (!filter_var($_POST['email'], FILTER_VALIDATE_EMAIL)) {
    echo "Email is not valid";
}

// 验证手机号
if (!preg_match("/^[0-9]{11}$/", $_POST['phone'])) {
    echo "Phone number is not valid";
}

When performing data verification, specific verification should be performed on the specific input data to ensure that the data is legal. sex.

4. Minimize database permissions
   Minimizing database permissions is one of the important measures to mitigate SQL injection attacks. When configuring the database, you should grant the minimum database permissions as needed. For example, only grant permissions to query, insert, and update data, and avoid deleting data or modifying the table structure. When performing database operations, you only need to use the minimum permissions granted, which can effectively reduce the threat of SQL injection attacks.

To sum up, methods to prevent SQL injection attacks in PHP language development include using parameterized queries, filtering and escaping input data, validating input data, and minimizing database permissions. Developers need to strengthen their security awareness and take effective measures to ensure the security of their websites.

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