# CTF Challenge Writeup: Mah Eyes are RED
## Challenge Information
- Name: Mah Eyes are RED- Category: Stegonography
## Challenge Analysis
A picture is given and the challenge name seems to have something to do with it...
![img/MahEyesareRed-1.png](img/MahEyesareRed-1.png)
The title of the challenge includes a capitalized word 'RED', this gives us a slight hint that something might be hidden on the 'Red plane' of the image.
## Solution
### Step 1: Analyze the file
We can use the **Stegsolve v1.3** by Caesum to analyze the file. During this proces we see that 'Red plane 0' contains some sort of cipher:
![img/MahEyesareRed-2.png](img/MahEyesareRed-2.png)
### Step 2: Decoding the symbols
After some intense searching, I've found an interesting cipher called the **Cistercian Numerals**:
![img/MahEyesareRed-3.png](img/MahEyesareRed-3.png)
The symbols present us with the following numbers:
```107 104 105 108 97 100 115```
### Step 3: Decoding the numbers
I used python to decode this information:
```python3 -c "print(chr(107) + chr(104) + chr(105) + chr(108) + chr(97) + chr(100) + chr(115))"```
![img/MahEyesareRed-4.png](img/MahEyesareRed-4.png)
### Step 4: Using the key
After a failing at decoding the image with the key, I've tested multiple different mutations of the key.Instead of 'khilads' I needed to use 'khiladi' with dynamic settings to extract a new image:
![img/MahEyesareRed-5.png](img/MahEyesareRed-5.png)
## Flag
`ICTF{Gr33n_Pl4nt_G0_Brrrr}`
## Resources
- Tool: [Stegsolve v1.3](http://www.caesum.com/handbook/Stegsolve.jar)- Reference: [Cistercian numerals](https://en.wikipedia.org/wiki/Cistercian_numerals)
## Writeup Author
- Twitter: [@Cyber8RU7U5](https://twitter.com/Cyber8RU7U5)