Tags: rev 

Rating:

# Write-up

## Intro
This challenge gives a vim script
To run the script, open vim, and input the command
```
:source task.vim
```

## How did I solve this challenge
A smart way is to build a compiler-like program that turns task.vim to ASM like script, making knowing the logic easier.
But I don't have programming skill QQ. So I only can use a stupid way to approach this challenge.

Divide task.vim to smaller vim scripts, conquering every small scripts.

Use human brain to turn task.vim to python script :(

custom_task_auto.vim combines scripts

You can run scripts one by one, simulating dynamic analysis

## File

decoder.py : first version of python script that equivalent to the logic of task.vim

decoder3.py : make first version of python more easier to understand

solve.py : written by [Frank Lin](https://github.com/eee4017) !

Original writeup (https://github.com/LJP-TW/CTF/tree/master/BalsnCTF-2019/reverse/vim).