## PicoCTF 2021- GET aHEAD

:::info
:bulb: This is a writeup for the GET aHEAD challenge in PicoCTF.
:::

### :eight_spoked_asterisk: The Challenge

Find the flag being held on this server to get ahead of the competition http://mercury.picoctf.net:15931/

### :mag_right: Breakdown

<p>
Clicking on the instance link, we are redirected to a website with two buttons that change the website background to red and blue respectively.
</p>


<p>
The challenge name suggests something to do with HTTP methods since the words GET and HEAD are emphasized.
</p>

### :mag_right: Some notes on HTTP Methods

<p>
The Hypertext Transfer Protocol (HTTP) works as a request-response protocol between a client and server.

Example: A client (browser) sends an HTTP request to the server; then the server returns a response to the client. The response contains status information about the request and may also contain the requested content.

The set of HTTP methods is given by: GET, POST, PUT, HEAD, DELETE, PATCH, OPTIONS, CONNECT, TRACE

GET is used to request data from a specified resource.

POST is used to send data to a server to create/update a resource.

HEAD is almost identical to GET, but without the response body. In other words, if GET /users returns a list of users, then HEAD /users will make the same request but will not return the list of users.

It is useful for checking what a GET request will return before actually making a GET request - a HEAD request can read the Content-Length header to check the size of the file, without actually downloading the file.

</p>

### :mag_right: Solution
Use the command line to enter

### :triangular_flag_on_post: The Flag!!

Running the shell command, we get the flag
:::spoiler
picoCTF{r3j3ct_th3_du4l1ty_82880908}:::