H@ctivityCon2020 Warmups | Common Place writeup

connect here: http://jh2i.com:50007

This was the prompt asked in the CTF, now If you go to this site, you get a web page like this,

You can see, they say the flag is clearly somewhere here, and that too on a common place, let’s just start with ./robots.txt, but no use on that.

then, I started to look for the hints which was left for us in the challenge prompt,

If you look at here, we have list of users, chatting about finding the flag, but particularly, one user messaged has he found the flag, and if you look closely on the username rfc5785, if you have guessed it kudos to you, yes RFC stands for Request for comments, its the way we define and use all protocols on the internet, and particulary rfc5785 defines a well known URI’s known as,

/.well-known/

So, if you go to this particular page, http://jh2i.com:50007/.well-known/ you will find the flag.txt file and by clicking on that you will get the flag for the challenge as,

And even funnier thing is, the challenge name is ‘Common Place’, well it directly gives us the meaning as ‘Well known’.