What considerations should be taken into account when executing shell commands within a PHP web application?

When executing shell commands within a PHP web application, it is important to consider security risks such as command injection attacks. To mitigate this risk, always validate and sanitize user input before passing it to the shell command. Additionally, use escapeshellarg() or escapeshellcmd() to escape any user input that is passed as arguments to the shell command. 

// Validate and sanitize user input
$user_input = $_POST['input'];
$validated_input = filter_var($user_input, FILTER_SANITIZE_STRING);

// Escape user input before passing it to shell command
$escaped_input = escapeshellarg($validated_input);

// Execute shell command
$output = shell_exec("your_command " . $escaped_input);

echo $output;

Keywords

shell commands PHP web application security risks escapeshellarg system() function

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