Nahamcon - Fast Hands

For that challenge, we have a webpage with a button

When we click it, a small window opens and disappears right away. When inspecting the page, clicking the button lauch the ctf() function.

function ctf() {
    window.open("./capture_the_flag.html", 'Capture The Flag', 'width=400,height=100%,menu=no,toolbar=no,location=no,scrollbars=yes');
}

That function opens a windw at /capture_the_flag.html location. In order to see it, we can just curl it :

curl http://challenge.nahamcon.com:31565/capture_the_flag.html

We are lucky, the flag is directly in the source code of the page.