TrueSecrets - HackTheBox Challenge Writeup

Challenge Information

Challenge Description

Our cybercrime unit has been investigating a well-known APT group responsible for several high-profile attacks on corporate organizations. The group developed a custom command & control (C&C) server. During a raid on the APT leader’s residence, a memory capture was obtained from their computer while it was still powered on. The objective is to analyze this memory dump to locate the source code of their custom C&C server.

Solution Overview

This forensics challenge requires analyzing a memory dump to extract sensitive artifacts. The investigation focuses on identifying and recovering the C&C server source code from the captured system memory.

Key Steps

1. Memory Dump Analysis

Begin by examining the memory capture file to understand its format and contents:

# Identify the memory dump type and metadata
file memory_dump.bin

# Check file size and initial content
ls -lh memory_dump.bin
hexdump -C memory_dump.bin | head -20

2. Volatility Framework Investigation

Use Volatility, the industry-standard memory forensics framework, to extract relevant data:

# List available profiles for the memory dump
volatility -f memory_dump.bin imageinfo

# Identify running processes
volatility -f memory_dump.bin --profile=<PROFILE> pslist

# Search for strings related to C&C or server code
volatility -f memory_dump.bin --profile=<PROFILE> strings | grep -i "server\|c2\|command"

3. Process and File Recovery

Extract processes and related files that may contain the server source code:

# Dump suspicious processes
volatility -f memory_dump.bin --profile=<PROFILE> memdump -p <PID> -D output/

# Recover file artifacts
volatility -f memory_dump.bin --profile=<PROFILE> filescan
volatility -f memory_dump.bin --profile=<PROFILE> dumpfiles -D output/

4. Source Code Extraction

Search recovered artifacts for the C&C server source code:

# Search for common programming patterns
grep -r "def\|class\|function\|import" output/ | grep -i "server\|command\|control"

# Identify code repositories or development artifacts
find output/ -name "*.py" -o -name "*.js" -o -name "*.cpp" -o -name "*.java"

# Extract and examine source files
cat output/recovered_source_code

Tools Used

• Volatility Framework - Memory forensics and analysis
• strings - Extract printable character sequences from binary data
• hexdump - Display file contents in hexadecimal format
• grep - Pattern matching and searching
• file - Identify file types

Key Learnings

1. Memory Forensics Fundamentals - Memory dumps contain volatile data that can reveal active processes, network connections, and in-memory artifacts that may not be present on disk.

2. Volatility Plugin Usage - Understanding profile selection and appropriate plugins is crucial for effective memory analysis. Different operating systems and kernel versions require different profiles.

3. APT Artifact Recovery - Advanced persistent threat actors often keep sensitive materials (like C&C server source code) in memory to avoid disk-based detection, making memory forensics essential for their investigation.

4. Systematic Evidence Collection - A methodical approach to memory analysis—starting with process enumeration, then narrowing focus to suspicious activities—is more effective than random searching.

5. Data Reconstruction - Recovered artifacts from memory may be fragmented and require careful reassembly and validation before analysis.

Flag Format: HTB{<redacted>}