What is the purpose of using shell commands in PHP, and what potential security risks should be considered?

When using shell commands in PHP, the purpose is to execute system commands or scripts directly from the PHP script. However, this can pose potential security risks such as command injection attacks if user input is not properly sanitized or validated. To mitigate these risks, it is important to carefully validate and sanitize any user input before passing it to shell commands. 

$user_input = $_POST['user_input'];

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

// Execute shell command
$output = shell_exec("ls " . $validated_input);

echo $output;

Keywords

shell commands PHP security risks system calls command injection

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