TMUCTF 2021 WriteUp-OSINT Challenges : The Foreign Student

Challenges Description:

Tarbiat Modares University has a foreign student. His name is Zedmondo. He has a very shady character. He always walks alone, eats alone, and never talks much. There are some rumors about him. Some people say he is a genius sociopath; some say he is just too self-involved. But one thing is obvious; he has a secret. Once, one of the students heard that he was talking about receiving some important documents via a private email. Maybe if we find his email, we can learn about his secret. Note: The flag format is TMUCTF{emailaddress}.

Google search “Tarbiat Modares University Zedmondo”:

Find the LinkedIn page. Seems like Zedmondo don’t like linkedin. He puts everything on his Github.

Go to GitHub page, I quickly go through all repositories, and focus on the “secretkey”.

There is a public key.

Look inside of public key, its a PGP public key.

Using any PGP tools to open the key, and you will find Zedmondo’s secret email.

Flag: TMUCTF{}