# TUCTF 2022 writeup
## Challenge description![Challenge description](assets/Description.png)
When we folow our network activites we can find that a cookies is present with boolean value :
![Cookie](assets/cookie.png)
I changed its value to "yes" insted of "no"..Nothing happening :(
When we send input we have a hidden message in namecheck page:
![Hidden](assets/hidden.png)
I tried many values for the cookie but nothing happend, next i did few researchs about Tornado and i found that's a python server and one of its vulnirabilities is that we can inject some python code like this  {{your_code}}
I typed this one and i ve got an interesting error : 
![Error](assets/error.png)
as we can see we have the path of the script, let's try to open it with this comand:
```{{open("/app/web2.py").read()}}```Amazing we have our flag!
![Flag](assets/flag.png)
