TXT Message

Challenge Statement

Author: @JohnHammond

Hmmm, have you seen some of the strange DNS records for the ctf.games domain? One of them sure is odd…

Solution

The challenge description suggests some strange DNS records with ctf.games I decided to lookup the DNS records. Further the title of the challenge says more. Since I put some time studying DNS protocol I am familiar with a TXT query type that pulls the text data given by the domain administrator.

Hence using the dig command from the bind with the query:

dig -t TXT ctf.games

We find a bunch of data in the answer section. It took me a few minutes but I recognized it is octal data. So plug it into Cyberchef and I got the flag.

On a unrelated note, I found there is a link to od in the challenge description which is a tool for octal dump while writing this writeup, suggesting we might encounter octal data. But I didn’t notice it.