I have solve half of the problem by decoding a base64 code that reveal the next URL(https://app.findbug.io/app/task/FinDBuG-CTF2019) but now i don't know what to find or where i tried it with burpsuite.
Here is the link for confirmation code:https://app.findbug.io/app/hacker/task
What you have to do is use HTTP OPTIONS method and look at the response then work your way from there
curl -X OPTIONS target
– tungsten Aug 26 '19 at 18:19OPTIONS /app/task/FinDBuG-CTF2019 HTTP/1.1
and repeat the request: – tungsten Aug 26 '19 at 18:39