Human Connection Challenge: Season 1 – Scanning Walkthrough Guide (Official Version)
Time’s Up! Congratulations to everyone who completed Lab 2: Scanning from the Human Connection Challenge: Season 1. In this walkthrough, I'll share some strategies for efficiently completing the lab, based on my perspective as the author. Remember, there are often multiple ways to approach a challenge, so if you used a different method and succeeded, that's perfectly fine! The goal is to learn, and I hope these notes help clarify any steps and reinforce key concepts for the next challenge. This challenge has now ended, but the lab remains available for practice. While prizes are no longer up for grabs, you can still complete the lab and use this walkthrough guide for support if needed. I’ve also used placeholders in some of the commands that would give away an answer directly, so if you see anything enclosed in angle brackets, such as <name server>, please make sure you replace it with the actual value, such as nameserver. With all that considered, let's get started. Overview Task: Identify the name server records of tinytown.bitnet. 1. What is the IP of the first name server for tinytown.bitnet? You’ll first need to open a Terminal on the Kali desktop. Next, you’ll need to query the DNS Server IP (found in the Machines panel) about the tinytown.bitnet domain using the nslookup (Name Server Lookup) tool. You’re specifically looking for NS (Name Server) records, so you can use the -type=ns parameter with nslookup to specify this: nslookup -type=ns tinytown.bitnet [DNS Server IP] The output of this command will return two name servers for the domain labelled with 1 and 2. Your next step is to identify what IP address is associated with the first name server (1). To do this, you can use nslookup along with the name server, domain, and DNS Server IP: nslookup <name server>1.tinytown.bitnet [DNS Server IP] This command will then return an IP address for the name server. 2. What is the IP of the second name server for tinytown.bitnet? As you’ve already identified both name servers, you’ll just need to run the previous command, except with the second (2) name server: nslookup <name server>2.tinytown.bitnet [DNS Server IP] You’ll then find the IP address associated with it. Task: Identify port service information for Target 1. 3. What service version is running on port 53? A network scanning tool like Nmap can help you identify the service version running on a specific port. To do this with Nmap, you can use the -sV option for service detection: nmap -sV [Target 1 IP Address] The output will show what service version is running on port 53. 4. What is the full service banner of port 22? There are a couple of ways to find the full service banner of port 22 – such as with Nmap or Netcat. If you’re using Nmap, you can modify the previous command to include the “banner” script along with the port number: nmap -sV -script=banner [Target 1 IP Address] -p22 The command line will then display the service banner from port 22. You can alternatively use netcat to manually connect to the SSH server. When a client connects, Netcat may present a banner that contains version information. To use Netcat, you’ll need the nc command along with the Target 1 IP address and specify you want to connect to port 22: nc [Target 1 IP Address] 22 When you run this command, the banner appears before the terminal hangs. Task: Identify a token on one of the ports. 5. What is the token? With the previous Nmap command, you initially found that three ports were open on Target 1. However, you’ll need to do a more thorough network scan to find another open port, one not initially found with the previous scans. To do this, you can expand your port scan to cover a much wider range by using Netcat to scan for open ports from 1 through 9000: nc -zvn <Target 1 IP Address> 1-9000 Here, -z will scan for listening services but won’t send any data, -v is verbose mode, which provides more detailed information, and -n tells Netcat not to resolve hostnames via DNS. This command will reveal a fourth open port. Now, you can use Netcat to connect to this port: nc <Target 1 IP Address> <open port> The token will then be displayed in the terminal. Task: Scan the TLS configuration on Target 2. 6. How many protocols are enabled? To scan for SSL/TLS configurations, you can use the sslscan tool. By default, sslscan scans port 443 and will return supported server ciphers, certificate details, and more. You can use sslscan like this: sslscan <Target 2 IP Address> The returned output will be verbose, but you can find and count the number of enabled protocols under the SSL/TLS Protocols subheading. 7. Name an enabled protocol. Using the previous output, name one of the enabled protocols. 8. What exploit are the protocols NOT vulnerable to? Using the same output, scroll down through the results until you find a subheading that’s named after a vulnerability and contains a similar string to: <Protocol> not vulnerable to <vulnerability name> The vulnerability has the same name as the subheading. Task: Identify and extract information from an SMB share on Target 3. 9. What Disk shared directory can you access? To extract information from an SMB (Server Message Block) share, you can use the smbclient tool. First, you’ll need to list the SMB shares on the target using the -L flag (the list/lookup option) with: smbclient -L //<Target 3 IP> You’ll then be prompted for a password, but you can press Enter to skip this. A list of SMB shares will then be displayed, three of which are shown to be a Disk type, so you know the answer will be one of these. You can now begin to go through the list and try to connect to the shares with: smbclient //<Target 3 IP>/<Sharename> However, this time when you’re prompted for a password and you press Enter, you might encounter a message when you try and connect to a share: NT_STATUS_ACCESS_DENIED If you attempt to connect to all shares, you’ll find you can connect to one share without a password. You’ll then be greeted with the following prompt to show the successful connection: smb: \> 10. What is the token stored in the directory? Now that you’re connected, you can execute commands to interact with the SMB share. If you run ls, you’ll find a token.txt file in the current directory. You can then download the file from the share onto your local machine with: get token.txt On the Kali desktop, open the Home folder and the token.txt will be inside. Open this file and find the token. 11. What is the username stored in the directory? After you’ve run ls in the SMB share, you’ll find not only token.txt, but also a file named creds.txt. Use the same command as you just did previously to download the file onto your machine: get creds.txt This file will also be downloaded to the Home folder, where you can find a username and password. Task: Identify open services on Target 3. Task: Connect to Target 3 with the previously found credentials. 12. What is the token stored in the user's /Documents directory? For this final task, you first need to scan the target using Nmap. You’ll find that if you attempt to scan the target without using the -Pn flag, you’ll get a response saying that the host seems down. However, if you run Nmap with -Pn, you’ll find some ports are open: nmap -Pn <Target 3 IP Address> However, the ports returned from this command don’t offer a way to connect to the target. You’ll also need to scan the 6000 most popular ports: nmap -Pn --top-ports 6000 <Target 3 IP Address> These results will now show two additional ports are open regarding the Web Services Management (Wsman) protocol, which is used to communicate with remote machines and execute commands. One of the tools that implement this protocol is Windows Remote Management (WinRM) which is Microsoft’s implementation of Wsman. Knowing this, you can now use Metasploit to interact with the target. In your terminal, run: msfconsole Once loaded, you can use the the following auxiliary module to connect to a system with WinRm enabled and execute a command with: set cmd ls You’ll then need to set the following options, using the credentials you found in the creds.txt file: set username <username> set password <password> set rhosts <Target 3 IP Address> Next, you need to set the cmd option with the command you want to run. If you use the ls command, you’ll be able to find what out files are in the directory you connect to: set cmd ls With all the options set, you can now run the module: run The results of the executed command will be printed on the screen and also saved to a directory, but both show the existence of a token.txt file in the current directory. You can now set the cmd option to type token.txt in Metasploit: set cmd type token.txt Once set, use the run command to send the updated command: run The contents of token.txt will then be displayed on the screen and outputted to a file. Tools For this challenge, you’ll use a range of tools including: Nslookup Nmap Netcat Sslscan Smbclient Metasploit Tips You can use different tools and parameters within those tools to scan for and find information, so don’t be afraid to try out a few different things! If you want to learn more about some of the tools within this lab, take a look at the following collections: Reconnaissance Nmap Infrastructure Hacking Introduction to Metasploit Post Exploitation with Metasploit Conclusion The steps I’ve laid out here aren’t the only way to find the answers to the questions, as long as you find the answer, you did it – well done! If you found another way to find some of these answers and think there’s a better way to do it, please post them in the comments below! I hope you enjoyed the challenge and I’ll see you for the next one.Building Your First Practical Lab (Part 2)
This is the second blog in a 2 part series that will walk you through the entire process of building your first custom practical lab. You’ll learn how to do everything from launching and configuring an EC2 instance in your AWS account to imaging it and seamlessly integrating it into our platform. In part 1 we showed you how to create and import your own machine. You can read part 1 here. In this blog, we’ll walk through building a simple Linux privilege escalation scenario as a working example. Our goal is to give you the foundational steps so you can confidently design scenarios tailored to your own creativity, environment, and organizational needs. The lab objective Ensure you are connected to the machine via the Ubuntu user for the steps below and not our lab user (lab-user). The objective of this lab is to read a token file. To do so, the user will need to escalate privileges via a misconfiguration. We will create a flag.txt file inside /root/ that contains a string that the user must read in the lab. sudo nano /root/flag.txt Add some content inside the file. This will act as a flag that can be used later to complete the lab. w3ll_don3_h4ck3r Save the file The lab challenge Now let’s set up the challenge! The goal is for lab-user to find a way to read the /root/flag.txt which is owned by root and not accessible to the lab-user by default. They will do this by exploiting a world-writable script that is executed as the root user in cron job. Create a directory to hold the script that lab-user can exploit. For this example, it's going to be a simple script that outputs the current time to a file (not very creative). sudo mkdir /opt/date_printer This script will be executed by root, but lab-user will have write permissions to it. The initial content will be benign, but the purpose of this lab is for the lab-user to identify the misconfiguration that allows them to modify it to read the /root/flag.txt file to retrieve the flag. Create a file for the script: nano /opt/date_printer/printer.sh Add the following content: #!/bin/bash echo "Running date_printer: $(date '+%Y-%m-%d %H:%M:%S')" >> /var/log/date.log Save the file. Next, set the misconfigured permissions that allow lab-user to write to the script, enabling privilege escalation. sudo chmod +x /opt/date_printer/printer.sh sudo chown root:root /opt/date_printer/printer.sh sudo chmod 666 /opt/date_printer/printer.sh Additionally, we want to configure the folder to ensure root owns it, but other users on the machine have access to it. sudo chown root:root /opt/date_printer sudo chmod 777 /opt/date_printer Now, let’s add a cron job to run the script we just created. For this scenario, we are going to edit the /etc/crontab file. Cron jobs in this file are generally used for system-wide cron tasks and are readable by anyone. This is good as it adds some breadcrumbs to our lab! If the user reads this file (a common check when looking for privilege escalation on Linux), they will see a script gets run every minute, and it will point them to investigate that script file. Edit the file nano /etc/crontab Add the following line at the end of the file. This line tells cron to execute /opt/date_printer/printer.sh every minute, as the root user * * * * * root /opt/date_printer/printer.sh Save the file. At this point, we have a configured image with a low-privilege lab-user account, which we will use to connect to the lab machine. We also have a cronjob vulnerability that our users attempting the lab have to exploit as the lab-user! For this lab, all the user has to do is find the script that is run by the cronjob and edit it to print the token in the file we added at /root/flag.txt. They could do this by easily updating the /opt/date_printer/printer.sh script to replace the contents with #!/bin/bash cat /root/flag.txt >> /var/log/date.log This one-liner will cat the contents of the /root/flag.txt file to the /var/log/date.log file, which the user can then read to get the token (there are other things we could do here as well, but for the purposes of this lab, let's keep it simple). Imaging and sharing the lab AMI Go back to the EC2 dashboard and find the running instance you just configured. Right-click on the EC2 machine, select Image and templates, and then Create image. Image name: Provide a descriptive name, e.g., “MyFirstCyberLab-AMI” or “Linux-PrivEsc-Lab-AMI”. Image description: Add a brief description, e.g., “Custom lab with lab-user password SSH and cron job privesc scenario.” Leave other settings at their default values. Click Create image. This will now create an AMI from the configured EC2 lab machine. Adding your custom AMI to your lab Navigate to Lab Builder and go to your custom lab via Manage > Create Lab. If you haven’t created one yet, go ahead and do so by selecting Create a new custom lab. On the Lab details page, we can give our lab a name and configure various other settings. For the purposes of this example, we’ll call it Linux CTF Challenge, and we’ll fill out the rest of the information to ensure our users know what the lab is all about. Lab description: This is a Linux CTF machine designed to test your ability in privilege escalation! Estimated Time Required: 30 Minutes Difficulty: 3 Learning outcomes: Understand how to exploit a common Linux misconfiguration What’s involved: Investigate the machine and find the misconfiguration that allows for privilege escalation. Next, we want to fill in the briefing panel. The briefing panel is the learning material that lets our lab users understand a bit about the topic and anything else they need to know to answer the questions. Since this is a CTF, we’ll give them limited information: Linux CTF This is a CTF lab scenario designed to test your ability to exploit a common misconfiguration in Linux that could result in privilege escalation. Your task in this lab is to read a flag located at /root/flag.txt. Good luck! Next, we want to add a Task. Tasks are what the user has to solve to complete the lab. For this example lab, we want to add a question to verify that they’ve read the flag in the /root/flag.txt file. Select Add task, which will bring up a library of task types. From the library, select Question. This will add a question to the lab task list, which we can then edit by selecting Edit. Update the question settings to the following: Question text: What is the flag found in the /root/flag.txt file? Answer: w3ll_don3_h4ck3r The next stage is to import our custom image. Select Systems and then click Add under the Virtual machine—EC2 type. This will add a new machine to your lab. Once the machine has been added, we want to configure it. Selecting Edit at the top right will open the machine's configuration editor. In the blue information box, we provide which region and, most importantly, which AWS account to share your image with so that our platform can use it in a lab. Within your own AWS account where you created your AMI for the lab image, click on the AMI, and at the bottom of the screen, you will see Permissions. Select Edit AMI permissions and Add account ID. This will open a box where you enter the Account ID that is displayed in Lab Builder. Click Share AMI. Now, copy the AMI ID of the machine you just shared and add it to the Lab Builder machine AMI ID section: Set the following configuration for the other sections in this editor: System Name: Your chosen name for the system you’re configuring. For this example, let's call it “Linux Machine”. Instance Type: t3.medium Connection Type: SSH Username: lab-user (or the username you set) Password: lab-user (or the password you set) Once you’ve configured your system, you can easily use it in Lab Builder by selecting Preview System on the system view. Assuming you’ve built everything correctly, you’ll get a shiny preview of your newly configured machine! This is a good time to run through your lab scenario to ensure it's working correctly. And that’s it—congratulations on building your first practical lab! At this point, you can spruce up your lab by adding additional questions or details to the briefing panel and publish your lab to your organization for them to enjoy. This powerful new feature puts the control directly in your hands, allowing you to create incredibly specific and challenging learning environments. These range from simple privilege escalation scenarios like this one to complex, multi-machine attack simulations. We can’t wait to see the innovative labs you'll create. In the meantime, if you need more ideas or support, use our Help Centre docs for Lab Builder.
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