Difficulty: Easy
Tags: Security, Engineer, CTF, Web Exploitation
Target IP: 10.114.144.190

Objective

Exploit a vulnerable web server to discover three specific ingredients required to help Rick transform back from a pickle into a human.

Reconnaissance & Enumeration

Initial Access

The challenge begins by accessing the web service via the target IP: http://10.114.144.190

Upon visiting the homepage, inspecting the Page Source reveals a critical comment exposing a username.

• Username: R1ckRul3s

The source code also hints at a subdirectory (assets/). Navigating to http://10.114.144.190/assets/ confirms the server environment.

• Server: Apache/2.4.41
• OS: Ubuntu
• Open Port: 80

Directory Bruteforcing

Using gobuster with a standard wordlist to find hidden directories and files:

gobuster dir -u http://10.114.144.190 -x php,txt,html -w /usr/share/wordlists/dirbuster/directory-list-2.3-medium.txt

Discovered Paths:

• /login.php
• /robots.txt
• /clue.txt

Exploitation

Credential Discovery

Reviewing the content of /clue.txt provides a hint regarding the ingredients.

Based on the context of the content from /robots.txt, the password is likely the famous catchphrase: Wubbalubbadubdub.

Attempting to log in at /login.php with the credentials:

• User: R1ckRul3s
• Pass: Wubbalubbadubdub

Result: Successful login.

Command Execution & Privilege Escalation

Once logged in, the dashboard restricts access to most sections, leaving only the “Commands” tab available. This suggests a restricted shell or command injection vulnerability.

Step 1: Environment Check

Executing basic commands to understand the environment:

• whoami → Returns current user.
• pwd → Returns current working directory.
• ls → Lists files in the current directory.

A file named Sup3rS3cretPickl3Ingred.txt is visible. Attempting to read it with cat fails because the command is disabled.

Step 2: Reading Files (Bypassing Restrictions)

Since cat is blocked, we try alternative commands like tac (which prints files in reverse line order, but still reads the content):

tac Sup3rS3cretPickl3Ingred.txt

Output: mr meeseek hair

Ingredient #1 Found: mr meeseek hair

Step 3: Finding the Second Ingredient

Next, we attempt to locate the user’s home directory to find the next clue:

ls ../../../home ls ../../../home/rick

A file named second ingredients is found. Note the space in the filename, requiring proper quoting:

tac '../../../home/rick/second ingredients'

Output: 1 jerry tear

Ingredient #2 Found: 1 jerry tear

Step 4: Finding the Final Ingredient

The final flag is typically located in the root directory (/root/). We check if the current user has sudo privileges:

sudo ls /root/

Surprisingly, the user can execute sudo without a password (a common misconfiguration in easy-level CTFs). We can now read the final file:

sudo tac /root/3rd.txt

Output: fleeb juice

Ingredient #3 Found: fleeb juice

Conclusion

By enumerating the web server, finding credentials via source code and clues, and exploiting a restricted shell with sudo privileges, we successfully retrieved all three ingredients.

Mitigations and Remediations

To prevent these specific vulnerabilities in a production environment, the following measures should be implemented:

1. Secure Coding Practices: remove all hardcoded credentials and internal paths from source code comments before deployment. Use automated scanning tools to detect secrets in code repositories.
2. Input Validation & Sandboxing: never pass user input directly to system shell commands. if command execution is required, use a strict whitelist of allowed command and sanitize inputs to prevent injection attacks.
3. Least Privilege Principle: the web server process should run with the minimum necessary permissions. Specifically, the user running the web application should not have sudo access, especially with NOPASSWD privileges.
4. Hardened Configuration: disable unnecessary commands (like tac) in restricted shells and configure the web server to block access to sensitive files types (e.g., .txt, .log) in public directories.

Final Answers

1. First Ingredient: mr meeseek hair
2. Second Ingredient: 1 jerry tear
3. Final Ingredient: fleeb juice

Difficulty: Easy
Tags: CTF, Web Exploitation, Privilege Escalation, Steganography
Target IP: 10.114.158.7

Objective

Exploit a vulnerable web server to discover two flags, one from the user and the other from the root user.

Reconnaissance & Enumeration

Initial Access

The challenge begins by accessing the web service via the target IP: http://10.114.158.7

Upon visiting the homepage, inspecting the Page Source reveals a critical comment exposing a relevant hint that mentions steganography.

Steganography: the practice of representing information within another message or physical object, in such a manner that the presence of the concealed information would not be evident to an unsuspecting person’s examination.

There is a potential hidden content in the image from the main page.

Scanning Services

Making a quick scan of the web would be useful to get more context of our scenario and to verify which services are available using nmap http://10.114.158.7

Discovered services:

• ftp
• ssh
• http

Exploitation

Credential Discovery

Accessing through ftp service firstly verifying if the anonymous user is available to execute ftp anonymous@10.114.158.7 where usually it does not require any password to login.

The anonymous user is enabled. Exploring if there is any relevant file by executing ls, there is a relevant instance called note_to_jake.txt

Getting the file into the local machine by using get note_to_jake.txt

Following the command cat note_to_jake.txt in our local machine to read the content of the file.

Looks like a potential user to log in within ssh service is jake and his password is weak, therefore a brute-force it might be quick to guess it. Using Hydra, hydra -V -l jake -P /usr/share/wordlists/rockyou.txt 10.114.158.7 ssh

Jake’s password has been guessed (987654321). Let’s proceed by impersonating Jake’s ssh session, ssh jake@10.114.158.7

Alternative Credential Discovery

Downloading the suspicious image that in the page source mentions steganography. Extracting detailed metadata from the image using the command exiftool.

There was nothing relevant. After a quick google search an interesting command steghide was found, steghide extract -sf brooklyn99.jpg

It contains a passphrase. It could be brute forced, therefore, after another quick google search if there is a way to make a brute force attack into an image that hides information. Commandstegcracker was found, stegcracker brooklyn99.jpg /usr/share/wordlists/rockyou.txt

Image has been cracked and a new result file has created, cat brooklyn99.jpg.out

In this path Holt’s password (fluffydog12@ninenine) has been discovered instead of Jake. Logging as Holt, ssh holt@10.114.158.7

Command Execution & Privilege Escalation

Once logged in as jake, the common corroboration of the following command brings more context of the session: pwd and whoami

Step 1: Environment Check (Jake)

Executing basic commands to understand the environment:

• whoami → Returns current user.
• pwd → Returns current working directory.

Step 2: Finding the User Flag

After exploring within Jake’s session there is an interesting file.

Looks like it is a hash value (ee11cbb19052e40b07aac0ca060c23ee), could be Holts hash password, but let’s try if it is the user flag.

User flag: ee11cbb19052e40b07aac0ca060c23ee

Alternative Step 1: Finding the User Flag (Holt)

Proceed by extracting the user flag, ls and cat user.txt

We got the same user flag ee11cbb19052e40b07aac0ca060c23ee

User flag: ee11cbb19052e40b07aac0ca060c23ee

Step 3: Privilege Escalation

After extracting the user flag, the remaining flag is the root user. Verifying the current session privileges using sudo -l

After knowing that the command less can be executed with admin privileges it is time to explore exploits by looking into GTFOBins to accomplish the privilege escalation.

Replicating the steps by executing first sudo less /etc/hosts followed afterwards !/bin/sh and verify that we are actually the root user.

Step 4: Finding the Root Flag

Navigating into the root folder and reading the text file using cat root.txt

Root flag: 63a9f0ea7bb98050796b649e85481845

Conclusion

By scanning the IP, finding credentials via ftp service and steganography techniques, and exploiting a vulnerable shell with sudo privileges for a specific command to escalate privileges to become the root user, we successfully retrieved both flags.

Mitigations and Remediations

To prevent these specific vulnerabilities in a production environment, the following measures should be implemented:

1. Secure Coding Practices: remove all hardcoded credentials and internal paths from source code comments before deployment. Use automated scanning tools to detect secrets in code repositories.
2. Least Privilege Principles: the ssh service should run with the minimum necessary permissions. Specifically, the user running in the service should not have sudo access, especially with NOPASSWD privileges.
3. Hardened Password Policy: enforce the usage of complex password to avoid a feasible brute force attack and restrict the amount of attempts to log in.

Final Answers

1. User flag: ee11cbb19052e40b07aac0ca060c23ee
2. Root flag: 63a9f0ea7bb98050796b649e85481845

Difficulty: Easy
Tags: CTF, Remote Code Execution, Forensic, Splunk
Target IP: 10.113.190.140

Objective

The main objective is to determine how an attacker exploited the server and subsequently perform a forensic examination of the host to identify the attacker’s footprints during the post-exploitation stage.

Exploiting the Server

Reconnaissance & Enumeration

Scanning Services

Making a quick scan of the target would be useful to get more context of our scenario and to verify which services are available using nmap 10.113.190.140

Discovered services:

• ssh
• http
• ibm-db2

ibm-db2 is a family of relational database products from IBM for storing, managing, and analyzing structured data.

Using nmap -p 50000 --script db2-das-info -sV 10.113.190.140 confirms the DB2 listener details to identify what host, port, and features are used to authenticate with a DB2 Client.

Looking at the output, we can extract the port 50000 is speaking HTTP and identifies a path to login manually to /login.html page.

Initial Access

Examining the http service using a web browser to gather more information: http://10.113.190.140

Upon visiting the homepage and inspecting the Page Source, anything relevant was found.

Examining the ibm-db2 service (which is actually running a web interface) using the web browser: http://10.113.190.140:50000/login.html

The service is operating an old version 2023.11.3 (build 147512)

Directory Bruteforcing

HTTP Service

Using gobuster with a standard wordlist to find hidden directories and files: gobuster dir -u http://10.113.190.140 -x php,txt,html -w /usr/share/wordlists/dirbuster/directory-list-2.3-medium.txt

Discovered Paths:

Nothing significant was revealed.

IBM-DB2 Service

Using gobuster with a standard wordlist to find hidden directories and files on the specific port: gobuster dir -u http://10.113.190.140:50000 -x php,txt,html -w /usr/share/wordlists/dirbuster/directory-list-2.3-medium.txt

Discovered Paths:

• login.html
• 400.html
• forgotPassword.html
• resetPassword.html

Vulnerability Research

Searching for a vulnerability for the specific version 2023.11.3 in JetBrains products.

There is an identified critical authentication bypass vulnerability tracked as CVE-2024-27198 an allows performing admin actions.

Exploitation

Command Execution & Remote Code Execution

Knowing there is a specific vulnerability to perform admin actions implies we will be able to execute code remotely. To make the exploitation process quick, Metasploit will help to automate the entire process. Launch msfconsole

Step 1: Select Exploit module

Searching for the specific exploit module, search cve:2024-27198

Select the exploit,exploit/multi/http/jetbrains_teamcity_rce_cve_2024_27198

Step 2: Execute the payload

Firstly, examining the required options to be filled in, show options

The required options in this scenario are:

• RHOSTS
• RPORT

Insert the needed values use set RHOSTS 10.113.170.99 and set RPORT 50000 and verify that are correctly selected using show options again.

Verify if the target is vulnerable after setting the options using check, then run the exploit with run

Step 3: Environment Check

Execute basic commands to understand the environment:

• whoami
• pwd
• ls

The flag is mentioned to be in the home flag. Therefore, navigate to the specific folder using cd /home and ls ubuntu

Read the content of the file flag.txt using cat ubuntu/flag.txt

Output:THM{faa9bac345709b6620a6200b484c7594}

Home folder flag Found:THM{faa9bac345709b6620a6200b484c7594}

Investigation

The IT department has provided the compromised server. The goal is to identify the attacker’s footprints in the post-exploitation stage. Splunk will be the first place to delve into the scenario.

• Username: splunk
• Password: analyst123

Splunk Examination

Malicious User

Access Splunk using the following URL, http://10.114.181.179:8000

It is required to explore the Search & Reporting app to investigate the logs from the brains service. Select the option Data Summary to extract all the entrances classified by specific criteria.

Since the attacker has been authorized as a root all the authentication logs are stored in auth.log

Display all records captured from auth.log by selecting the time frame as All time

Since the next flag mentions user, looking at the section called INTERESTING FIELDS does not mention anything about name or user initially, but there is an option to select more fields

In the Field column there is an instance called name. By displaying the field, there is an interesting line that mentions the user.

Name of the backdoor user which was created on the server after exploitation: eviluser

By including the filter of the known malicious user, we can identify the day of the attack.

It is vital to inspect 7/14/24

Malicious Package

Within the Data Summary, the Sourcetypes section mentions packages. Therefore, the next step is to review its content. Before anything, apply an advisable filter to reduce the entrances by selecting Date & Time Range and specifying the date 07/14/2024

Now there are all the instances with the source type packages that were registered in the system before 7/24/24

The first instance contains a suspicious name called datacollector

Name of the malicious-looking package installed on the server: datacollector

Plugin Installed

To look for the malicious plugin, it is mandatory to first review the service that was attacked. It is called teamcity. Therefore, look in the Data Summary within the Sources section where teamcity-activities.log.

Repeating the same temporal criteria as for the malicious package and apply an additional filter *plugin*. The entries generated by Splunk will be the most relevant to inspect based on the scenario.

Looking at the first instance it reveals a bizarre name AyzzbuXY and it is a zip file. This is the plugin.

Name of the plugin installed on the server after successful exploitation: AyzzbuXY.zip

Conclusion

By scanning the IP, identifying the service on port 50000 as a JetBrains TeamCity instance, and exploiting a known vulnerability (CVE-2024-27198) that allows a remote code execution as the root user, we successfully retrieved the initial flag.

By accessing Splunk to review Data Summary where was registered the authentication and TeamCity service activities were registered as logs, we successfully retrieved the forensic flags.

Mitigations and Remediations

To prevent these specific vulnerabilities in a production environment, the following measures should be implemented:

1. Patch Management: immediately update JetBrains TeamCity to the latest version to mitigate known CVEs like CVE-2024-27198.
2. Network Segmentation: restrict access to administrative interfaces (like TeamCity login page) to trusted IP ranges only, rather than exposing them publicly.
3. Log Monitoring & SIEM: implement robust logging and real-time monitoring (like Splunk) to detect anomalous user creation, suspicious package installations, and unauthorized plugin activity.
4. Principle of Least Privilege: ensure that services do not run with unnecessary root privileges and that user accounts are strictly controlled.

Final Answers

1. Home folder flag: THM{faa9bac345709b6620a6200b484c7594}
2. Name of the backdoor user which was created on the server after exploitation: eviluser
3. Name of the malicious-looking package installed on the server: datacollector
4. Name of the plugin installed on the server after successful exploitation: AyzzbuXY.zip

Difficulty: Easy
Tags: CTF, Web Exploitation, Privilege Escalation
Target IP: 10.113.133.17

Objective

Act as Bob, a security engineer, to identify the vulnerabilities exploited on the tourism website in the production environment, retrieve the hidden flags, and restore the website to its original state.

Reconnaissance & Enumeration

The challenge begins by accessing the web service via the target IP: http://10.113.133.17

Minified Javascript: the process of removing unnecessary characters from JavaScript code, such as whitespace, comments, and line breaks, without changing its functionality.

By mentioning “minified” it means that the JavaScript code was modified. Inspecting the Page Source reveals several critical clues:

<!-- Rest PHP code and html content -->


<!DOCTYPE html>
<html lang="en">


<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Tourism Website</title>
 
    <script src='/tailwind.min.js'></script> <!-- THIS IS OFFICIAL FILE - DO NOT CHANGE IT -->
  <script src='custom.min.js'></script> <!-- THIS IS CUSTOM JS FILE-->
  <link rel="stylesheet" href="/style.css">
</head>


<body>
  <!-- Navigation Bar -->
  <nav class="bg-gray-900 text-white p-6">
    <div class="flex justify-between items-center">
      <a href="/" class="text-lg font-bold">Tourism MHT </a>
      <ul class="flex items-center gap-5">
	  <!--  <li><a href="https://alexanderroca.dev/img" class="hover:text-gray-300">Logs</a></li>  Please keep all images in this folder -->
      <!--  <li><a href="./logs" class="hover:text-gray-300">Logs</a></li>  DevOps team to check and remove it later on -->


        
              
      </ul>
    </div>
  </nav>

  <!-- Main Content -->
  <main class=" mx-auto py-8  h-[80vh] flex items-center justify-center">

    <div class="rounded overflow-hidden shadow-lg bg-white  p-8 flex ">
		        <h2 class="text-gray-700 text-3xl py-6"> FINALLY HACKED !!! I HATE MINIFIED JAVASCRIPT</h2>
	    </div>

  </main>

  <!-- Footer -->
  <footer class="bg-gray-900 text-white flex items-center justify-center">
    <div class="text-center p-4">
      <p>&copy; 2023 Tourism.mht. All rights reserved.</p>
    </div>
  </footer></body>

</html>

It mentions PHP at the top of the source code. Moreover, there are relevant comments:

• custom.min.js: Custom JS file
• /img: Keeps all the images
• ./logs: To check logs and remove later for DevOps

Service Analysis

Inspecting the Network tab in browser development tools reveals a GET request to custom.min.js

Downloading and examining the file reveals the content is encoded in Hexadecimal (hex)

What type of encoding is used by the hackers to obfuscate the JavaScript file? hex

Using CyberChef to decode the hex string reveals the hidden message DIRECTORY LISTING IS THE ONLY WAY

What is the flag value after deobfuscating the file? DIRECTORY LISTING IS THE ONLY WAY

Directory Enumeration

Following the hints from the source code comments:

1. Image Directory (/img)

Visiting http://10.113.133.17/img reveals an Apache server running on Ubuntu. No immediate flags are found in the images.

2. Logs Directory (/logs)

Visiting http://10.113.133.17/logs reveals a file named email_dump.txt

What is the name of the file containing email dumps? email_dump.txt

Reading the content of email_dump.txt:

From: Bob <bob@tourism.mht>
To: Mark <mark@tourism.mht>
Subject: API Credentials

Hey Mark,

Sorry I had to rush earlier for the holidays, but I have created the directory for you with all the required information for the API.
You loved SSDLC so much, I named the API folder under the name of the first phase of SSDLC.
This page is password protected and can only be opened through the key. THM{100100111}

See ya after the holidays

Bob.

The email mentions the API folder is named after the first phase of SSDLC. The first phase is Planning.

The logs folder contains email logs and has a message for the software team lead. What is the name of the directory that Bob has created? Planning

The email also provides the password/key: THM{100100111}

What is the key file for opening the directory that Bob has created for Mark? THM{100100111}

Exploitation

Credential Discovery & API Abuse

Step 1: Accessing the Planning Directory

Visiting http://10.113.133.17/planning requires a password. Entering the key THM{100100111} grants access.

Step 2: Enumerating Users

Inside, we find instructions for an API endpoint: GET http://MACHINE_IP/api/?customer_id=1

The objective is to find specific user details via the API.

Finding User ID 5: Calling http://10.113.133.17/api/?customer_id=5 returns information for a client:

There is an information from the customer id=5, where the email is john@traverse.com and it is a client user.

What is the email address for ID 5 using the leaked API endpoint? john@traverse.com

Finding the Admin User: Iterating through IDs reveals that id=3 belongs to an administrator. Calling: http://10.113.133.17/api/?customer_id=3 reveals:

What is the ID for the user with admin privileges? 3

It displays the endpoint to get access /realadmin and it reveals an email realadmin@traverse.com, name admin and password admin_key!!!

What is the endpoint for logging in as the admin? Mention the last endpoint instead of the URL. /realadmin

Step 3: Gaining Admin Access

Navigating to http://10.113.133.17/realadmin:

Logging in with the credentials found (realadmin@traverse.com / admin_key!!!) grants access to the admin panel.

Step 4: Environment Check

The admin panel offers options to execute system commands.

• System Owner: output www-data (equivalent to whoami)
• Current Directory output /var/www/html/realadmin (equivalent to pwd)

Using the browser’s Network tab to intercept the POST request, we can modify the payload to execute arbitrary commands.

Sending commands=ls -lsa reveals the directory contents.

Two critical files are identified:

• thm_shell.php: likely the web shell used by the attacker.

Can you find the name of the web shell that the attacker has uploaded? thm_shell.php

• renamed_file_manager.php: a renamed file manager tool

What is the name of the file renamed by the attacker for managing the web server? renamed_file_manager.php

A password for the file manager is also displayed in the output:THM{10101}

Step 5: Restoring the Website

Accessing http://10.113.133.17/realadmin/renamed_file_manager.php with the passwordTHM{10101} opens the file manager.

Locating the index.php, we observe it has been modified to display “FINALLY HACKED” message.

Editing the file to remove the malicious message restores the site.

The final flag of this room is in the file: THM{WEBSITE_RESTORED}

Can you use the file manager to restore the original website by removing the “FINALLY HACKED” message? What is the flag value after restoring the main website? THM{WEBSITE_RESTORED}

Conclusion

By analyzing the source code for hidden comments and obfuscated JavaScript, we identified the encoding method and a hint for directory listing. Leveraging directory enumeration, we found an email dump that revealed the naming convention for a protected directory and the password to access it. Inside, we discovered an insecure API endpoint that allowed us to enumerate users and harvest admin credentials. Finally, using the admin panel to execute commands, we identified the attacker’s web shells, accessed the file manager, and restored the compromised website.

Mitigations and Remediations

To prevent these specific vulnerabilities in a production environment, the following measures should be implemented:

1. Code Review & Sanitization: remove all hardcoded credentials, internal paths, and debug messages from source code before deployment. Avoid leaving comments that hint at hidden directories.
2. Disable Directory Listing: configure the web server (Apache/Nginx) to disable directory listing (Options -Indexes) to prevent attackers from browsing file structures.
3. Secure API Endpoints: implement proper authentication and authorization checks on all API endpoints. Do not expose sensitive user data (emails, passwords) via unauthenticated or poorly secured GET requests.
4. Input Validation & Sandboxing: restrict the ability of web applications to execute system commands. If command execution is necessary, ensure strict input validation and sandboxing to prevent arbitrary code execution.

Final Answers

1. What type of encoding is used by the hackers to obfuscate the JavaScript file? hex
2. What is the flag value after deobfuscating the file? DIRECTORY LISTING IS THE ONLY WAY
3. What is the name of the file containing email dumps? email_dump.txt
4. What is the name of the directory that Bob has created? Planning
5. What is the key file for opening the directory that Bob has created for Mark? THM{100100111}
6. What is the email address for ID 5 using the leaked API endpoint? john@traverse.com
7. What is the ID for the user with admin privileges? 3
8. What is the endpoint for logging in as the admin? Mention the last endpoint instead of the URL. /realadmin
9. Can you find the name of the web shell that the attacker has uploaded? thm_shell.php
10. What is the name of the file renamed by the attacker for managing the web server? renamed_file_manager.php
11. Can you use the file manager to restore the original website by removing the “FINALLY HACKED” message? What is the flag value after restoring the main website? THM{WEBSITE_RESTORED}