How can escaping characters impact the execution of shell commands in PHP?

Escaping characters is important in PHP to prevent unintended execution of shell commands. Failure to properly escape characters can lead to command injection vulnerabilities where an attacker can manipulate the input to execute arbitrary commands on the server. To mitigate this risk, always use functions like escapeshellarg() or escapeshellcmd() to properly escape input before using it in shell commands. 

$user_input = $_POST['user_input'];
$escaped_input = escapeshellarg($user_input);
$output = shell_exec("ls " . $escaped_input);
echo $output;

Keywords

escaping characters shell commands PHP execution impact

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