Type: Walkthrough
Difficulty: Easy
Tags: Web
Meta Tags: Walkthrough, Walk-through, Write-up, Writeup
Subscription type: Free
Description:
Learn about how you request content from a web server using the HTTP protocol
Room link: https://tryhackme.com/room/httpindetail
HTTP is what's used whenever you view a website, developed by Tim Berners-Lee and his team between 1989-1991.
HTTP is the set of rules used for communicating with web servers for the transmitting of webpage data, whether
that is HTML, Images, Videos, etc.
HTTPS is the secure version of HTTP. HTTPS data is encrypted so it not only stops people from seeing the data
you are receiving and sending, but it also gives you assurances that you're talking to the correct web server
and not something impersonating it.
Answer: HyperText Transfer Protocol
Answer: Secure
On the mock webpage on the right there is an issue, once you've found it, click on it. What is the challenge flag?
Answer: THM{<REDACTED>}
If you’ve used the internet, you’ve used a URL before. A URL is predominantly an instruction on how to access a
resource on the internet.
The below image shows what a URL looks like with all of its features (it does not use all features in every request).
Scheme: This instructs on what protocol to use for accessing the resource such as HTTP, HTTPS, FTP (File
Transfer Protocol).
User: Some services require authentication to log in, you can put a username and password into the URL to log in.
Host: The domain name or IP address of the server you wish to access.
Port: The Port that you are going to connect to, usually 80 for HTTP and 443 for HTTPS, but this can be hosted on
any port between 1 - 65535.
Path: The file name or location of the resource you are trying to access.
Query String: Extra bits of information that can be sent to the requested path. For example, /blog? id=1 would tell
the blog path that you wish to receive the blog article with the id of 1.
Fragment: This is a reference to a location on the actual page requested. This is commonly used for pages with long
content and can have a certain part of the page directly linked to it, so it is viewable to the user as soon as they
access the page.
It's possible to make a request to a web server with just one line GET / HTTP/1.1.
But for a much richer web experience, you’ll need to send other data as well. This other data is sent in what is
called headers, where headers contain extra information to give to the web server you’re communicating with, but
we’ll go more into this in the Header task.
GET / HTTP/1.1
Host: tryhackme.com
User-Agent: Mozilla/5.0 Firefox/87.0
Referer: https://tryhackme.com/
Example response:
HTTP/1.1 200 OK
Server: nginx/1.15.8
Date: Fri, 09 Apr 2021 13:34:03 GMT
Content-Type: text/html
Content-Length: 98
<html>
<head>
<title>TryHackMe</title>
</head>
<body>
Welcome To TryHackMe.com
</body>
</html>
Answer: HTTP/1.1
Answer: Content-Length
HTTP methods are a way for the client to show their intended action when making an HTTP request.
There are a lot of HTTP methods but we'll cover the most common ones, although mostly you'll
deal with the GET and POST method.
This is used for getting information from a web server.
This is used for submitting data to the web server and potentially creating new records
This is used for submitting data to a web server to update information
This is used for deleting information/records from a web server.
Answer: POST
Answer: PUT
Answer: DELETE
Answer: GET
In the previous task, you learnt that when a HTTP server responds, the first line always contains a status code
informing the client of the outcome of their request and also potentially how to handle it. These status codes
can be broken down into 5 different ranges:
100-199 - Information Response:
These are sent to tell the client the first part of their request has been accepted and they should continue
sending the rest of their request. These codes are no longer very common.
200-299 - Success:
This range of status codes is used to tell the client their request was successful.
300-399 - Redirection:
These are used to redirect the client's request to another resource. This can be either to a different webpage
or a different website altogether.
400-499 - Client Errors:
Used to inform the client that there was an error with their request.
500-599 - Server Errors:
This is reserved for errors happening on the server-side and usually indicate quite a major problem with the
server handling the request.
| Status code | Description |
|---|---|
| 200 - OK | The request was completed successfully. |
| 201 - Created | A resource has been created (for example a new user or new blog post). |
| 301 - Moved Permanently | This redirects the client's browser to a new webpage or tells search engines that the page has moved somewhere else. |
| 302 - Found | Similar to the above permanent redirect, but as the name suggests, this is only a temporary change. |
| 400 - Bad Request | This tells the browser that something was either wrong or missing in their request. |
| 401 - Not Authorised | You are not currently allowed to view this resource until you have authorised with the web application. |
| 403 - Forbidden | You do not have permission to view this resource whether you are logged in or not. |
| 405 - Method Not Allowed | The resource does not allow this method request. |
| 404 - Page Not Found | The page/resource you requested does not exist. |
| 500 - Internal Service Error | The server has encountered some kind of error with your request that it doesn't know how to handle properly. |
| 503 - Service Unavailable | This server cannot handle your request as it's either overloaded or down for maintenance. |
Answer: 201
Answer: 404
What response code might you receive if the web server cannot access its database and the application crashes?
Answer: 503
Answer: 401
Headers are additional bits of data you can send to the web server when making requests.
Although no headers are strictly required when making a HTTP request, you’ll find it difficult to view a website properly.
These are headers that are sent from the client (usually your browser) to the server.
Host: Some web servers host multiple websites so by providing the host headers you can tell it which one you require,
otherwise you'll just receive the default website for the server.
User-Agent: This is your browser software and version number, telling the web server your browser software helps it
format the website properly for your browser and also some elements of HTML, JavaScript and CSS are only available in
certain browsers.
Content-Length: When sending data to a web server such as in a form, the content length tells the web server how much
data to expect in the web request. This way the server can ensure it isn't missing any data.
Accept-Encoding: Tells the web server what types of compression methods the browser supports so the data can be made
smaller for transmitting over the internet.
Cookie: Data sent to the server to help remember your information (see cookies task for more information).
These are the headers that are returned to the client from the server after a request.
Set-Cookie: Information to store which gets sent back to the web server on each request (see cookies task for more
information).
Cache-Control: How long to store the content of the response in the browser's cache before it requests it again.
Content-Type: This tells the client what type of data is being returned, i.e., HTML, CSS, JavaScript, Images, PDF,
Video, etc. Using the content-type header the browser then knows how to process the data.
Content-Encoding: What method has been used to compress the data to make it smaller when sending it over the internet.
Answer: User-Agent
Answer: Content-Type
Answer: Host
You've probably heard of cookies before, they're just a small piece of data that is stored on your computer. Cookies are
saved when you receive a "Set-Cookie" header from a web server. Then every further request you make, you'll send the cookie
data back to the web server. Because HTTP is stateless (doesn't keep track of your previous requests), cookies can be used
to remind the web server who you are, some personal settings for the website or whether you've been to the website before.
Cookies can be used for many purposes but are most commonly used for website authentication.
Answer: Set-Cookie
Hint: The answer is the text starting with the letters THM{...
Request:
GET /room HTTP/1.1
Host: tryhackme.com
User-Agent: Mozilla/5.0 Firefox/87.0
Content-Length: 0
Rewsponse:
HTTP/1.1 200 Ok
Server: nginx/1.15.8
Fri, 18 Apr 2025 17:26:25 GMT
Content-Type: text/html; charset=utf-8
Content-Length: 252
Last-Modified: Fri, 18 Apr 2025 17:26:25 GMT
<html>
<head>
<title>TryHackMe</title>
</head>
<body>
Welcome to the Room page THM{<REDACTED>}
</body>
</html>
Answer: THM{<REDACTED>}
Request:
GET /blog HTTP/1.1
Host: tryhackme.com
User-Agent: Mozilla/5.0 Firefox/87.0
Content-Length: 0
Rewsponse:
HTTP/1.1 200 Ok
Server: nginx/1.15.8
Fri, 18 Apr 2025 17:29:5 GMT
Content-Type: text/html; charset=utf-8
Content-Length: 250
Last-Modified: Fri, 18 Apr 2025 17:29:5 GMT
<html>
<head>
<title>TryHackMe</title>
</head>
<body>
Viewing Blog article 1 THM{<REDACTED>}
</body>
</html>
Answer: THM{<REDACTED>}
Request:
DELETE /user/1 HTTP/1.1
Host: tryhackme.com
User-Agent: Mozilla/5.0 Firefox/87.0
Content-Length: 0
Response:
HTTP/1.1 200 Ok
Server: nginx/1.15.8
Fri, 18 Apr 2025 17:30:57 GMT
Content-Type: text/html; charset=utf-8
Content-Length: 250
Last-Modified: Fri, 18 Apr 2025 17:30:57 GMT
<html>
<head>
<title>TryHackMe</title>
</head>
<body>
The user has been deleted THM{<REDACTED>}
</body>
</html>
Answer: THM{<REDACTED>}
Hint: Click the settings cog to add a parameter to the PUT request
Request:
PUT /user/2 HTTP/1.1
Host: tryhackme.com
User-Agent: Mozilla/5.0 Firefox/87.0
Content-Length: 0
Response:
HTTP/1.1 200 Ok
Server: nginx/1.15.8
Fri, 18 Apr 2025 17:32:39 GMT
Content-Type: text/html; charset=utf-8
Content-Length: 251
Last-Modified: Fri, 18 Apr 2025 17:32:39 GMT
<html>
<head>
<title>TryHackMe</title>
</head>
<body>
Username changed to admin THM{<REDACTED>}
</body>
</html>
Answer: THM{<REDACTED>}
Hint: Delete the parameter requests from the last task, and add two more (username & password).
Request:
POST /login HTTP/1.1
Host: tryhackme.com
User-Agent: Mozilla/5.0 Firefox/87.0
Content-Length: 0
Response:
HTTP/1.1 200 Ok
Server: nginx/1.15.8
Fri, 18 Apr 2025 17:35:22 GMT
Content-Type: text/html; charset=utf-8
Content-Length: 256
Last-Modified: Fri, 18 Apr 2025 17:35:22 GMT
<html>
<head>
<title>TryHackMe</title>
</head>
<body>
You logged in! Welcome Back THM{<REDACTED>}
</body>
</html>
Answer: THM{<REDACTED>}
For additional information, please see the references below.