Rating:

# Tenable Capture the Flag 2023

## Cyberpunk Cafe

> This trend of restaurants getting rid of hard copies of their menus is kinda annoying, but this new cyberpunk-themed cafe is taking it a bit too far. Check out what they gave me.
>
> Author: N/A
>
> [`challenge.txt`](https://github.com/D13David/ctf-writeups/blob/main/tenablectf23/stego/cyberpunk_cafe/challenge.txt)

Tags: _stego_

## Solution
A file with the following content is given.

```
Thanks for visiting the Cyberpunk Cafe! Please use the code below to see what we have to offer:

0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001111111000100111110110000011111110000000010000010101111101111010000100000100000000101110101010011110111100101011101000000001011101010000010110010100010111010000000010111010101011111000100110101110100000000100000101010110000110010001000001000000001111111010101010101010101011111110000000000000000010111110010000100000000000000000001001111100010110001100110111110000000001111110000010101110101111011001010000000010011011110111101111100111101110100000000011011000011111100100100101001001000000000000101111011101101011011110000000000000011110100010001100010100111100100100000000001010100000010010010011011010101000000001101000110100111111010010101010000000000000011111111001100110101110100101100000000000001001100101000000111101001001000000001001111111111000110100010010010010000000010111001111000010111101101000101000000000001010111001111010100000101101000000000000011110110010111010111100111010010000000011100111110010100110100100100000100000000001100010111100101111010111111000000000001111011000001110110100001111101110000000000000000100101011100000110001010100000000111111101111010010010110101010101000000001000001011001110010000101000110100000000010111010001010000011111111111001100000000101110100110011011110111110011101000000001011101011011000100101111000110110000000010000010000011110010011011000100000000000111111100011011111010000111000001000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
```

Trying to decode this bitstring didn't lead to anything so I did a bit closer inspection of the pattern. Since if looking closely some sort of `pixel islands` can be recognized. For better visibility I converted 0 to ▓ and 1 to ░ and put the result in a texteditor.

```
▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓░░░░░░░▓▓▓░▓▓░░░░░▓░░▓▓▓▓▓░░░░░░░▓▓▓▓▓▓▓▓░▓▓▓▓▓░▓░▓░░░░░▓░░░░▓░▓▓▓▓░▓▓▓▓▓░▓▓▓▓▓▓▓▓░▓░░░▓░▓░▓░▓▓░░░░▓░░░░▓▓░▓░▓░░░▓░▓▓▓▓▓▓▓▓░▓░░░▓░▓░▓▓▓▓▓░▓░░▓▓░▓░▓▓▓░▓░░░▓░▓▓▓▓▓▓▓▓░▓░░░▓░▓░▓░▓░░░░░▓▓▓░▓▓░░▓░▓░░░▓░▓▓▓▓▓▓▓▓░▓▓▓▓▓░▓░▓░▓░░▓▓▓▓░░▓▓░▓▓▓░▓▓▓▓▓░▓▓▓▓▓▓▓▓░░░░░░░▓░▓░▓░▓░▓░▓░▓░▓░▓░▓░░░░░░░▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓░▓░░░░░▓▓░▓▓▓▓░▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓░▓▓░░░░░▓▓▓░▓░░▓▓▓░░▓▓░░▓░░░░░▓▓▓▓▓▓▓▓▓░░░░░░▓▓▓▓▓░▓░▓░░░▓░▓░░░░▓░░▓▓░▓░▓▓▓▓▓▓▓▓░▓▓░░▓░░░░▓░░░░▓░░░░░▓▓░░░░▓░░░▓░▓▓▓▓▓▓▓▓▓░░▓░░▓▓▓▓░░░░░░▓▓░▓▓░▓▓░▓░▓▓░▓▓░▓▓▓▓▓▓▓▓▓▓▓▓░▓░░░░▓░░░▓░░▓░▓░░▓░░░░▓▓▓▓▓▓▓▓▓▓▓▓▓▓░░░░▓░▓▓▓░▓▓▓░░▓▓▓░▓░▓▓░░░░▓▓░▓▓░▓▓▓▓▓▓▓▓▓▓░▓░▓░▓▓▓▓▓▓░▓▓░▓▓░▓▓░░▓░░▓░▓░▓░▓▓▓▓▓▓▓▓░░▓░▓▓▓░░▓░▓▓░░░░░░▓░▓▓░▓░▓░▓░▓▓▓▓▓▓▓▓▓▓▓▓▓▓░░░░░░░░▓▓░░▓▓░░▓░▓░░░▓░▓▓░▓░░▓▓▓▓▓▓▓▓▓▓▓▓▓░▓▓░░▓▓░▓░▓▓▓▓▓▓░░░░▓░▓▓░▓▓░▓▓▓▓▓▓▓▓░▓▓░░░░░░░░░░▓▓▓░░▓░▓▓▓░▓▓░▓▓░▓▓░▓▓▓▓▓▓▓▓░▓░░░▓▓░░░░▓▓▓▓░▓░░░░▓░░▓░▓▓▓░▓░▓▓▓▓▓▓▓▓▓▓▓░▓░▓░░░▓▓░░░░▓░▓░▓▓▓▓▓░▓░░▓░▓▓▓▓▓▓▓▓▓▓▓▓▓░░░░▓░░▓▓░▓░░░▓░▓░░░░▓▓░░░▓░▓▓░▓▓▓▓▓▓▓▓░░░▓▓░░░░░▓▓░▓░▓▓░░▓░▓▓░▓▓░▓▓▓▓▓░▓▓▓▓▓▓▓▓▓▓░░▓▓▓░▓░░░░▓▓░▓░░░░▓░▓░░░░░░▓▓▓▓▓▓▓▓▓▓▓░░░░▓░░▓▓▓▓▓░░░▓░░▓░▓▓▓▓░░░░░▓░░░▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓░▓▓░▓░▓░░░▓▓▓▓▓░░▓▓▓░▓░▓░▓▓▓▓▓▓▓▓░░░░░░░▓░░░░▓░▓▓░▓▓░▓░░▓░▓░▓░▓░▓░▓▓▓▓▓▓▓▓░▓▓▓▓▓░▓░░▓▓░░░▓▓░▓▓▓▓░▓░▓▓▓░░▓░▓▓▓▓▓▓▓▓▓░▓░░░▓░▓▓▓░▓░▓▓▓▓▓░░░░░░░░░░░▓▓░░▓▓▓▓▓▓▓▓░▓░░░▓░▓▓░░▓▓░░▓░░░░▓░░░░░▓▓░░░▓░▓▓▓▓▓▓▓▓░▓░░░▓░▓░░▓░░▓▓▓░▓▓░▓░░░░▓▓▓░░▓░░▓▓▓▓▓▓▓▓░▓▓▓▓▓░▓▓▓▓▓░░░░▓▓░▓▓░░▓░░▓▓▓░▓▓▓▓▓▓▓▓▓▓▓░░░░░░░▓▓▓░░▓░░░░░▓░▓▓▓▓░░░▓▓▓▓▓░▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓
```

Then I noticed that increasing and decreasing did move the islands and I thought that this might be a 2D image. Not knowing the width and height I increased and decreased the window size of my texteditor until...

![](https://raw.githubusercontent.com/D13David/ctf-writeups/main/tenablectf23/stego/cyberpunk_cafe/code.png)

... this piece of art appeared. Scanning the QR code reveiled the flag.

Flag `flag{br1ng_b4ck_phys1c4l_menu5}`

Original writeup (https://github.com/D13David/ctf-writeups/blob/main/tenablectf23/stego/cyberpunk_cafe/README.md).