[NeverLAN 2019] - Cookie Monster

Description:

Solution Author:

Lucian Nitescu, as part of jmp 0xc0ffee team.

Solution:

After accessing the challenge URL (https://challenges.neverlanctf.com:1110/) I observed the cookie Red_Guy's_name as seen in the following screenshot from Burp Suite:

Also, the response provided us with some additional information as seen in the highlighted areas:

I decided to take that information an use the Google search engine in order to retrieve more information.

I discovered that the name of the "red guy" in "Cookie Monster" is actually called Elmo. I changed the cookie value in order as such:

The flag is: flag{YummyC00k13s}