TryHackMe Protocols and Servers Walkthrough | Telnet, HTTP, FTP, SMTP, POP3, IMAP

INTRODUCTION

Task 1: Introduction

No answer is required for this task.

Task 2: Telnet

Q. To which port will the telnet command with default parameters connect?

A. 23

Explanation

Telnet is a network protocol used to remotely connect to another computer over TCP/IP and execute commands. It operates on Port 23 (TCP) and follows a client–server model.

What Telnet Does

• Allows remote login to another machine
• Provides command-line access to remote systems
• Helps test open ports and services

Common Telnet Commands

• telnet <hostname>
• telnet <hostname> <port>
• open <hostname> <port>
• close
• quit

Task 3: Hypertext Transfer Protocol (HTTP)

Q. Launch the attached VM. From the AttackBox terminal, connect using Telnet to MACHINE_IP 80 and retrieve the file flag.thm. What does it contain?

A. THM{e3eb0a1df437f3f97a64aca5952c8ea0}

Explanation

HTTP (Hypertext Transfer Protocol) is the foundation of communication on the web. Browsers and servers use it to request and deliver webpages, images, videos, and APIs.

Ways to Access a Webpage

• Web Browser (Chrome, Firefox, etc.)
• Command-line tools such as curl or wget
• Programming languages like Python or JavaScript
• APIs returning JSON or XML data
• Raw TCP/Telnet (for educational purposes)

In this example We will connect to the website server using telnet command. telnet 10.48.174.71 80. After connecting run the below command.

GET /flag.thm HTTP/1.1

You will see the flag - THM{e3eb0a1df437f3f97a64aca5952c8ea0}

Task 4: File Transfer Protocol (FTP)

Q. Using an FTP client, connect to the VM and try to recover the flag file. What is the flag? (Username: frank, Password: D2xc9CgD)

A. THM{364db6ad0e3ddfe7bf0b1870fb06fbdf}

Steps

• Run ftp MACHINE_IP
• Enter the provided username and password
• Use ls to list files
• Use get filename to download the file
• Read the file contents to retrieve the flag

Flag: THM{364db6ad0e3ddfe7bf0b1870fb06fbdf}

Task 5: Simple Mail Transfer Protocol (SMTP)

Q. Using the AttackBox terminal, connect to the SMTP port of the target VM. What is the flag that you can get?

A. THM{5b31ddfc0c11d81eba776e983c35e9b5}

Process

Connect to the SMPT server using telnet using the below command

Run: telnet MACHINE_IP 25.
You will see the output, where you will get the flag.

Trying 10.48.186.14... 

Connected to 10.48.186.14. 

Escape character is '^]'. 

220 bento.localdomain ESMTP Postfix THM{5b31ddfc0c11d81eba776e983c35e9b5}

Task 6: Post Office Protocol 3 (POP3)

Q1. Connect to the VM (10.48.186.14) at the POP3 port. Authenticate using the username frank and password D2xc9CgD. What is the response you get to STAT?
A1. +OK 0 0

Q2. How many email messages are available to download via POP3 on 10.48.186.14?
A2. 0

Process

Connect to the POP3 service using: telnet 10.48.186.14 110

Authenticate with: username frank and password D2xc9CgD

Run the command:STAT

output: +OK 0 0

In POP3, this means:

• 0 messages
• 0 total size (bytes)

Task 7: Internet Message Access Protocol (IMAP)

Q. What is the default port used by IMAP?

A. 143

Explanation

Task 8: Summary

Click proceed to complete the room.