Effective ways to prevent PHP injection attacks

Methods to prevent PHP injection attacks include: Use parameterized queries to prevent SQL injection. Use the filter input function to filter the passed in values. Use the mysqli_real_escape_string() function to escape special characters. Use whitelist and blacklist validation to filter dangerous characters or patterns.

Effective method to prevent PHP injection attacks

A PHP injection attack is a method that exploits vulnerabilities in PHP applications to insert malicious Attack type for SQL queries. Such attacks can lead to data leakage, database corruption, or even system takeover.

Prevention methods

1. Parameterized query

Using parameterized queries can prevent SQL injection attacks. This technique uses placeholders (?) to replace actual values ​​in SQL queries and passes the values ​​to MySQL before executing the query.

Sample code:

$stmt = $conn->prepare("SELECT * FROM users WHERE username = ?");
$stmt->bind_param("s", $username);

2. Use filter function

to filter input to prevent injection attacks. Incoming values ​​can be filtered using PHP's filter_input() function.

Sample code:

$username = filter_input(INPUT_POST, 'username', FILTER_SANITIZE_STRING);

3. To escape special characters

you can use mysqli_real_escape_string() Function escapes input special characters to prevent them from being interpreted as SQL commands.

Sample code:

$username = mysqli_real_escape_string($conn, $username);

4. Use whitelist and blacklist verification

Whitelist and blacklist verification can Filter out dangerous characters or patterns.

Sample code:

// 白名单
$allowed_chars = ['a', 'b', 'c'];
if (!in_array($char, $allowed_chars)) {
  // 输出错误消息
}

// 黑名单
$banned_chars = ['<', '>', '"', '\''];
if (preg_match('/[' . implode('', $banned_chars) . ']/', $input)) {
  // 输出错误消息
}

Practical case

The following is a demonstration of how to use parameterized queries and filter functions to prevent injection attacks Code example:

// 获取用户输入
$username = filter_input(INPUT_POST, 'username', FILTER_SANITIZE_STRING);

// 准备和执行查询
$stmt = $conn->prepare("SELECT * FROM users WHERE username = ?");
$stmt->bind_param("s", $username);
$stmt->execute();

Conclusion

By implementing these precautions, you can protect your PHP application from injection attacks.

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