What potential security risks should be considered when executing Shell commands in PHP scripts?

When executing Shell commands in PHP scripts, potential security risks include command injection attacks where user input is not properly sanitized, leading to unintended commands being executed. To mitigate this risk, always validate and sanitize user input before passing it to shell commands. Additionally, consider using PHP functions like `escapeshellarg()` or `escapeshellcmd()` to escape user input. 

$user_input = $_POST['user_input'];

// Validate and sanitize user input
$sanitized_input = escapeshellarg($user_input);

// Execute Shell command with sanitized input
$output = shell_exec("ls " . $sanitized_input);
echo $output;

Keywords

Shell commands PHP scripts security risks command injection escapeshellarg

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