What are the potential pitfalls of implementing a user online feature in PHP?

One potential pitfall of implementing a user online feature in PHP is not properly handling session management, which can lead to security vulnerabilities such as session hijacking or session fixation attacks. To mitigate this risk, ensure that sessions are securely managed and that sensitive user data is not exposed. 

// Start session
session_start();

// Set session variables
$_SESSION['user_id'] = $user_id;

// Validate session
if (!isset($_SESSION['user_id'])) {
    // Redirect user to login page
    header("Location: login.php");
    exit();
}

Keywords

security vulnerabilities SQL injection session hijacking cross-site scripting data validation

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