CTF WriteUps Virtual Hard Disk

Virtual Hard Disk

One of the first things I learnt when I started learning to hack was linux. It was fun until I hit a ceiling of understanding about the differences in Operating Systems, what’s a Shell, Kernel, etc.

But once I got better I started developing a liking towards the terminal and how the Linux operating system is better than say Windows, or worse in some cases. How none of them is superior, nor the other inferior. We shall find out with this challenge.

Be careful, a lot of fake galfs around.

  • Category: Forensic
  • Challenge File: challenge (DOS/MBR boot sector)

Solution:

1. Use FTKImager to identify any suspicious file

After a long time of exploring (clicking and clicking –_--), this weird file 666c61672e747874.jpg contain two data streams Flag and Key.

acectf-forensic6.png

Taking a look what are the strings in it:

Flag: CTCHHW{7t3_h1hw3p3sq3_s37i33r_a0l_4li_a3}
Key: Key='cryforme'

This is a Vigenere Cipher which uses key to perform rotation cipher. Chunk it into a decoder will give us the flag

2. Decode Vigenere encoded string

acectf-forensic7.png

Flag: ACECTF{7h3_d1ff3r3nc3_b37w33n_y0u_4nd_m3}