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# System prepended metadata

title: BITSKRIEG CTF 2025 WRITE-UP

---

# BITSKRIEG CTF 2025 WRITE-UP
Welcome to my BITSKRIEG CTF 2025 write-up. This is my second international CTF that I have competed in. Sadly, I could only solve one challenge in this competition. But still, any solved challenge must be written down.


## Table of Contents
1. OSINT
    a. HotPause
    

## 1. OSINT
### a. HotPause
![Challenge Page](https://hackmd.io/_uploads/SyyvqJYt1x.png)
This challenge gave you a video titled "concert.mp4" which I assume will be our OSINT target, along with a Netcat command which will directly made you enter the challenge.

After I ran this command in Kali Linux, I got this output
```
Welcome secret agent. We've recovered a video from our aliases infiltrating our next target. Your first task is to find out what is our target city.
City Name (all caps):
```
As usual, I used Google Lens to identify a specific location of a photo.
![Step 1 (Finding The City Name)](https://hackmd.io/_uploads/SJ4CgCdYke.png)
There is a reel on Instagram that has hashtag with the city name of where the video was taken. It was a Coldplay concert on India, specifically in "Ahmedabad".

After entering the first answer, I got another output.
```
Correct!
Well done! Now you need to find out where our partner agent was sitting.
Block Letter with Bay (For e.g. A5, B1, etc.)
```
This is quite a tricky question since you have to guess correctly from the videographer point of view.

After searching through the internet, I found this image of the detailed seating of this concert.
![Step 2 (Find Where The Videographer Sat)](https://hackmd.io/_uploads/S1knV0utJl.png)
You can see that the videographer sat on the right side of the stage from this point of view. So I only focused on P and Q seat rows.
![frame_790](https://hackmd.io/_uploads/By4yD0OF1e.jpg)
After trying different variations, I found the exact position where the videographer were sitting, which was on "Q3"

Second answer done, this is what I got as an output.
```
Correct!
Good work. Now when you hear Chris Martin say "You know I love you so..." for the beat drop, I need you to use your Flipper Zero to send the correct data stream, replicating the wristbands colour exactly. Our enemies should have no clue. Good Luck.
Data Stream:
```
This question took 10% percent of my sanity to only find what the data stream format was.

I searched "coldplay data stream flipper zero" on Google and found this site.
https://www.geekzone.co.nz/forums.asp?forumid=73&topicid=317776
![Step 3 (Find The Correct Data Stream)](https://hackmd.io/_uploads/ByxtY0utJg.png)
A user named "BarTender" made a post about using a Flipper Zero to mess up the wristbands visual. He also gave a GitHub link for more details about it. https://github.com/danielweidman/flipper-pixmob-ir-codes

Digging through the repositories, I found a specified file which contains all the colors for the wristbands.
![Step 4 (Finding The Specified Color)](https://hackmd.io/_uploads/r1aT5AdFkl.png)
I clicked the "pixmob_all_colors.ir and scanned through the file. Then, I finally found the answer that I was looking for.

The colors of the wristbands when the beat drop was "yellow", which has a connection on the name of the song itself which titled "Yellow". So I searched through the repository and finally found the yellow data stream.
```
# 
name: YEL
type: raw
frequency: 38000
duty_cycle: 0.330000
data: 1400 1400 700 700 700 700 1400 2800 700 2100 700 700 700 1400 700 1400 1400 2800 1400 2800 700
```
By entering the data stream on the last question, I finally got the flag.
```
Correct!

Good job agent. Here's your flag, should you choose to accept it: BITSCTF{that_was_a_very_weird_OSINT_challenge_afd12df}
```
Flag: BITSCTF{that_was_a_very_weird_OSINT_challenge_afd12df}


Well, I guess that's all for my BITSKRIEG CTF 2025 write-up since I can only solve one challenge.

With heartfelt grace, I treasure your kind regard for my write-up, as words find solace in the eyes that cherish them.

"Like shadows that dance in the hush of night,
I drift beyond the silver light.
A whisper lost in falling rain,
Yet echoes linger, soft—remain.

BLACKRAIN fades, but not in vain,
For every drop recalls my name.
Until the storm and stars align,
Farewell, but not goodbye in time."

BLACKRAIN (STELK_CSC), BITSKRIEG CTF 2025, Sancoale, India.
