```py
import requests

url = 'http://source.darkarmy.xyz/'

r = requests.get(url, headers={
'user-agent': '9e9',
})

print(r.text)

# darkCTF{changeing_http_user_agent_is_easy}
```

Original writeup (https://github.com/csivitu/CTF-Write-ups/blob/master/DarkCTF%202020/Web/Source/exploit.py).