Hack the Box - Blackhole Challenge

ctf
challenges
#1

After downloading our challenge file we have to extract the zip file. We got another archive.zip file so we have to unzip archive.zip again to see what’s inside.

We can see a file hawking and it’s JPEG image somehow. let’s try changing the extension and try to open see if it works.

mv hawking hawking.jpeg | xdg-open hawking.jpeg

Now that we have an image we can try some basics of stego cheatsheet.

Let’s try steghide

If you look at base64 it’s encoded twice.

But unfortunately it’s not our flag it’s encoded in cipher.

TFN{Z3hqD_x3F_fT3_n4eFmDp5_S3f_K0g_p0iZ}

It’s a https://www.dcode.fr/caesar-cipher after doing some google research and shift 12.