You are currently viewing Cyber Investigator CTF Challenges – Part 1

Cyber Investigator CTF Challenges – Part 1

This is the first part of my Cyber Investigator CTF Challenge walkthroughs. The challenges are very beginner-friendly and good for anyone who is new to OSINT. If you’re planning to complete these challenges yourself, stop here and only come back for a hint if you get stuck.

Signals Intelligence: foreigntransmission

This challenge included a .wav-file, an audio file, with a recording of a woman speaking Chinese. The challenge was simple: to find out the code she was speaking out loud.

As I do not have the slightest understanding of the Chinese language, I searched for a tool that could transcript the audio file to text. I tried an automated subtitle-generator tool that didn’t require registration, flixier.com. Turned out it was fantastic and I got the code in written form just by clicking a button.

Put that up in Google Translate and boom, we have our code!

Covert Operations: aviator

This challenge included a video clip of an airplane taking off. The question was: Can you find the latest possible date that the video was taken?

I watched the video a couple of times and noted everything of importance: the beginning showed a LASER Airlines aircraft, there was a flag and then the other aircraft taking off which was American Airlines.

After reading through the LASER Airlines Wikipedia page, I found an interesting piece of information: due to the decision taken by the United States Government, on May 15, 2019, commercial and cargo flights to Venezuela from the United States were suspended indefinitely.

I matched the flag with Venezuela, and did some further research. I found several news articles stating that on March 15, 2019, American Airlines suspended all flights to and from Venezuela. This just proves that you should never trust only one source, always use multiple sources if possible.

The video could not have been taken after March 15, 2019, as after that American Airlines did not operate in Venezuela.

Cyber Crime: d3c0d3r

The next challenge was a bit cryptic. However, we can see that the first part is ASCII code and the next part is binary. There are tools like the dcode.fr that can both identify and decode ciphers.

The first part decodes to: There are 195 independent sovereign nations in the world, but which one is it?

The binaries decode to: II . IV VII VIII VI I V , XLV . VI II I I IX II

By changing the Roman numerals into numbers, we get 2.478615, 45.621192. Now that looks very much like coordinates so let’s hit that up on Google maps.

Google maps drops us somewhere in Somalia, which is the correct answer and we have successfully decoded the challenge.

Crime Scene Investigation: jigsaw

As the title suggests, it’s time for a jigsaw puzzle! I tried searching for a tool that would automate jigsaw puzzle solving using AI, and even found one on Github, but after trying it out it didn’t really work so I decided to do this manually. All I needed was a small piece of the image that I can throw into a reverse image search (I usually find TinEye to find what I need, but there are of course other ones you can try as well). I pieced up the following part of the image:

Next, I uploaded that to TinEye and got promising results:

The first result was what I was searching for and I successfully found the full name of the person in the image.