Cct2019 Tryhackme -

The CCT2019 room on TryHackMe is widely considered one of the most grueling and technically demanding forensic challenges on the platform. Originally designed for the 2019 U.S. Navy Cyber Competition Team (CCT) Assessment, it tests the absolute limits of a researcher's packet analysis and reverse engineering skills. 🏗️ Challenge Structure

The room is not a standard "step-by-step" tutorial. It is a raw assessment consisting of legacy files from the Navy's 2019 competition.

PCAP Focus: The core of the challenge revolves around deeply nested traffic captures. Difficulty: Officially rated as Insane.

Time Estimate: Expect to spend significantly more than the suggested 180 minutes. 🛠️ Key Skills & Tools Required

To successfully navigate CCT2019, you need mastery over several specialized domains: 1. Advanced Traffic Analysis

Wireshark & Tshark: Basic filtering is not enough; you must be comfortable extracting data from non-standard protocols.

USB Forensic: One task involves analyzing USB traffic captures to reconstruct file exchanges. 2. File Carving & Recovery

Binwalk: Essential for finding hidden or compressed files inside the PCAPs.

Integrity is Key: If you fail to recover a file perfectly in step one, later stages become impossible. 3. Reverse Engineering

Binary Analysis: Later tasks require decompiling and reversing .NET applications.

Logic Puzzles: You will encounter mathematical constraints (like product/sum conditions) that require scripting solutions (e.g., Python) to solve. ⚠️ Common Pitfalls cct2019 tryhackme

Red Herrings: The creators intentionally included false leads. If you find yourself doing steganography (stego) early on, you are likely in a "rabbit hole".

Extraction Errors: Standard extraction tools sometimes corrupt the payloads. Using command-line tools like tshark is often the more reliable path. 💡 Final Verdict

CCT2019 is a "must-try" for aspiring Blue Teamers and forensic analysts who want to experience a high-stakes military-style assessment. It rewards persistence and "out of the box" thinking rather than encyclopedic knowledge of vulnerabilities. Recommended For: Advanced forensic students.

Professionals preparing for the GCFE or GCFA certifications. Anyone who enjoys complex, multi-layered puzzles. If you'd like to tackle this, Tips on reverse engineering .NET binaries using dnSpy. Help identifying red herrings in the initial PCAP. CCT2019 - TryHackMe

CCT2019 is a high-difficulty, "Insane" rated room on TryHackMe that features legacy challenges originally created for the U.S. Navy Cyber Competition Team (CCT) 2019 Assessment. Unlike standard "grab-the-flag" rooms, this challenge focuses on analytical depth, traffic reconstruction, and reverse engineering. Room Structure & Challenges

The room is divided into four distinct tasks, each focusing on a specific domain of cybersecurity:

Task 1: pcap1 (Network Forensics) – This task requires deep analysis of packet captures. It includes "red herrings" to mislead investigators and emphasizes recovering files in their entirety to progress.

Task 2: re3 (Reverse Engineering) – A complex reverse engineering challenge involving a .NET executable. Users must analyze the binary's logic (often using tools like dnSpy) to find specific combinations of values.

Task 3: for1 (Forensics) – A forensic challenge that often involves digging through disk images or specific artifacts to uncover hidden evidence.

Task 4: crypto1 (Cryptography) – A layered crypto challenge. Some sub-tasks (like crypto1c) may require custom scripting to solve, as standard online tools may not support the specific variants used. Key Skills and Tools Required The CCT2019 room on TryHackMe is widely considered

To successfully navigate the CCT2019 room, participants generally need proficiency in several advanced areas:

Packet Analysis: Mastery of Wireshark is essential for reconstructing traffic and identifying misleading paths.

Reverse Engineering: Knowledge of assembly or .NET decompilation is necessary for Task 2.

Data Extraction: Tools like binwalk are used to find and extract compressed files or hidden data embedded within other files (e.g., extracting a .pcapng from within another capture).

Scripting: Tasks like the crypto challenges often require Python scripts to automate brute-force attempts or custom decoding. Strategic Tips

Validate Everything: The room is designed with a "Zero Trust" mindset; don't assume an artifact is valid just because it looks correct at first glance.

Avoid Rabbit Holes: Pay close attention to hints. For the pcap challenge, if you find yourself doing steganography or extensive reverse engineering, you have likely strayed into a "rabbit hole".

Sequence Matters: Especially in the network forensics task, failing to recover the initial file completely can prevent you from solving subsequent steps.

The CCT2019 room on TryHackMe, designed for the U.S. Navy Cyber Competition Team, offers legacy challenges focusing on analytical depth, structured assessments, and validation of evidence. Key components include PCAP analysis, traffic reconstruction, reverse engineering, and layered forensics, emphasizing a zero-trust mindset. Learn more at TryHackMe. CCT2019 TryHackMe Challenge: Analytical Depth Over Speed

Exploiting SSTI:

We can escalate the injection to read system files. A common payload: From the list of subclasses, search for file

 self.__class__.__mro__[2].__subclasses__()

From the list of subclasses, search for file or subprocess.Popen. With careful chaining, we achieve remote code execution.

First Flag (user.txt): After gaining a basic shell (e.g., via a reverse shell payload injected into the template), we navigate to /home/chester or /home/user to find user.txt.

Content of user.txt: A 32-character hash (typical for TryHackMe rooms).

Phase 3: Exploitation (Getting the Flag)

Based on the note, navigate to the hidden directory.

  1. Navigate: http://<MACHINE_IP>/secret/
  2. Result: You might see a message like "Secret Development Folder" or a directory listing.

The Twist: This room is slightly tricky. You won't find a flag immediately on the webpage. If you look deeper (or run another gobuster scan on this directory), you might find nothing. However, check the source code of the pages you visit.

Alternative Path (The common solution): In CCT2019, the "secret" directory often contains a file or leads to another clue. If you are stuck, try looking at the robots.txt file, or simply look closer at the files in the web root.

Wait, let's re-evaluate the common path for this specific room:

  1. Look at robots.txt (http://<MACHINE_IP>/robots.txt).
  2. It often disallows a directory, for example: /passwords/.
  3. Navigate to /passwords/.
  4. You will find a file (e.g., credentials.txt or similar).

Finding the Flag: Inside one of these directories (often /secret/ or linked from the notes), there is a file named flag.txt or similar, OR the flag is displayed directly on a webpage.

Actually, on CCT2019 specifically, the goal is often simpler than a full system breach for the main flag.

Solution Step:

  1. Access /secret/.
  2. Inside that folder, there is often a file called flag.txt.
  3. Open it.
  4. Flag Found.

(Note: There may be multiple flags or a user flag later, but the primary flag is often hidden in these web directories.)

9. Mitigation & Lessons Learned

Check cron jobs:

cat /etc/crontab

Sometimes a script runs as root every few minutes.