What are the potential risks of using URL redirection in PHP?

One potential risk of using URL redirection in PHP is the possibility of open redirection attacks, where an attacker can manipulate the redirection URL to redirect users to malicious websites. To mitigate this risk, it is important to validate and sanitize the input URL before performing the redirection. 

// Validate and sanitize the input URL before redirection
$redirectUrl = filter_var($_GET['url'], FILTER_VALIDATE_URL);

if($redirectUrl !== false){
    header("Location: $redirectUrl");
    exit();
} else {
    // Redirect to a safe default URL if the input URL is invalid
    header("Location: safe_default_url.php");
    exit();
}

Keywords

URL redirection PHP security risks vulnerability open redirect

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