Parzaan-Cybersecurity_Task_1

GDG Recruitments 2026: Cybersecurity Task 1 Writeup

Introduction

This document outlines my investigative process for Task 1 and Task 1B. As a beginner in cybersecurity, my goal was to apply a structured methodology to each challenge. While I was unable to retrieve the final flags within the time limit, the following sections document the tools I explored, the logic I applied, and the technical roadblocks I encountered during my attempts.

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Task 1A: The 3-Level CTF

Objective: Formulate a strategy to recover three hidden fragments for the flag format: Gdg{part1_part2_part3}.

Level 1: Hidden Files & Directory Traversal

• The Strategy: My first instinct was to check for "hidden" files that don't appear in standard directory listings, as these are often used to store hints or flag fragments in CTF environments.
• The Investigation: 1. I navigated to the gdg_part1 directory and executed ls -la to view all contents, including those prefixed with a dot (.). 2. I located a .hint file and attempted to decode its contents (which appeared to be Base64).
• The Roadblock: While I identified the likely hidden files, I struggled to bypass the final permission layer or encoding required to read the actual fragment text before the time expired.

Level 2: Steganography (Image Analysis)

• The Strategy: Given the image heheheha.png, I looked for data hidden within the file's pixels or metadata.
• The Investigation:

  1. I used exiftool to scan for hidden comments, unusual timestamps, or suspicious software tags in the metadata.

  2. I researched LSB (Least Significant Bit) encoding, where fragments are hidden in the binary "noise" of the image colors.

  3. I attempted to use zsteg to isolate different bit planes (Red, Green, Blue) to find a text string.

• The Result: I found suspicious patterns in the Red channel, but I was unable to successfully extract a readable string during the challenge window.

Level 3: Automation vs. The "QR Bomb"

• The Strategy: Faced with 3,000 QR codes, I realized manual analysis was a "rabbit hole" designed to waste time.
• The Investigation:
  1. I designed a Python logic (linked in qr_solver.py) to automate the search. The plan was to use PIL for image handling and pyzbar for decoding.
  2. The Logic: Iterate through all 3,000 files and print() only the content that matched the "Gdg" prefix.
• The Roadblock: I ran into a "to hell with dependencies" part where the pyzbar library could not link to the necessary libzbar system drivers on my local machine. I spent most of the remaining time troubleshooting the environment rather than running the final scan.

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Task 1B: apple_pi3 (Binary Analysis)

Objective: Audit a Linux binary to see if sensitive data can be recovered from an obfuscated state.

1. Static Analysis Attempts

• I used the strings command to peer into the binary. I noticed references to strcmp and printf, which suggested the program performs a comparison between user input and a "secret" string stored internally.

2. Dynamic Analysis & Tracing

• The Approach: I attempted to use ltrace ./apple_pie to catch the binary de-obfuscating its secret in memory.
• The Theory: If the program de-obfuscates the flag at runtime, ltrace should capture the plain-text flag as an argument to the strcmp function right before checking my input.

3. Debugging (GDB)

• I tried setting a breakpoint at the main function using GDB. My goal was to step through the assembly code and inspect the registers (RDI/RSI) where the comparison happens.
• The Result: Due to my limited experience with assembly and the binary's basic obfuscation, I was unable to correctly identify the specific memory address holding the flag before the session ended.

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Technical Hurdles & Failure Analysis

• Technological Roadblocks: The biggest hurdle was environment configuration (specifically for the QR-scanner and GDB). This taught me that having a "ready-to-go" toolkit is just as important as knowing the theory.
• Logic vs. Execution: My logic for identifying the vulnerabilities (LSB in stego, strcmp in binaries) was sound, but my I couldn't execute it as fast as I am super new to this.
• Final Reflection: Although I did not capture the flags, this task provided an immense learning curve regarding how developers attempt to hide data and how a security researcher systematically peels back those layers.