The white box is composed of two parts: 1. The first part is link named Home and pointing to http://natas7.natas.labs.overthewire.org/index.php?page=home 2. The second is a link About pointing to http://natas7.natas.labs.overthewire.org/index.php?page=about
Clicking on Home brings us to the same page, except that there is a message saying "this is the front page". Clicking on About changes the message to "this is the about page". If we look at the source of the page, we see a hint:
<!−− hint: password for webuser natas8 is in /etc/natas webpass/natas8 −−>Ok, then we just include this file as the php variable (instead of home or about), that is to say, we navigate to http://natas7.natas.labs.overthewire.org/index.php?page=/etc/natas_webpass/natas8.
The message changes to DBfUBfqQG69KvJvJ1iAbMoIpwSNQ9bWe