old-54 -- Misc

URL: https://webhacking.kr/challenge/bonus-14/

The character on website keeps changing:

Can also be observed in Network:

IMAGE

In the source:

x=run();
function answer(i){
  x.open('GET','?m='+i,false);
  x.send(null);
  aview.innerHTML=x.responseText;
  i++;
  if(x.responseText) setTimeout("answer("+i+")",20);
  if(x.responseText=="") aview.innerHTML="?";
}

curl "https://webhacking.kr/challenge/bonus-14/?m=[0-40]" `
  -H "Cookie: PHPSESSID=3052403292" `
  -H "Referer: https://webhacking.kr/challenge/bonus-14/"

FLAG{a7981201c48d0ece288afd01ca43c55b}