OffSec Echo Response Writeups

Overview

This repository contains comprehensive writeups for all 8 weeks of the OffSec Echo Response challenge series. Each writeup represents a complete security investigation with detailed analysis, evidence collection, and remediation strategies.

Challenge Structure

Week	Challenge	Focus Area	Primary Skills
0	Tutorial Challenge	Path Traversal & Log Analysis	Web Security, Forensics
1	ProtoVault Breach	Database Security & Cloud Infrastructure	Database Forensics, Cloud Security
2	Stealer's Shadow	Advanced Persistent Threat & Malware	Threat Hunting, Malware Analysis
3	Quantum Conundrum	Cryptography & Algorithm Analysis	Crypto Analysis, Reverse Engineering
4	Echo Trail	Cloud Security & Humanitarian Impact	Azure Security, Incident Response
5	Emerald Anomaly	Supply Chain Attack & Code Analysis	Supply Chain Security, Malware Analysis
6	Nullform Vault	Advanced Malware & Reverse Engineering	Malware Analysis, Binary Forensics
7	Codex Circuit	Collaboration Tool Security & Insider Threats	Network Forensics, Insider Threat Analysis
8	Last Ascent	ICS/SCADA Security & Critical Infrastructure	Industrial Security, System Forensics

Writeup Structure

Each writeup follows a consistent structure designed to provide comprehensive coverage:

Core Sections

• Executive Summary - High-level overview and key findings
• Investigation Strategy - Methodology and approach
• Key Discoveries - Critical findings and breakthrough moments
• Technical Analysis - Detailed technical breakdown
• Evidence Collection - Forensic artifacts and analysis
• Timeline Reconstruction - Complete attack chronology
• Impact Assessment - Business and security implications
• Remediation Strategy - Immediate and long-term fixes
• Lessons Learned - Key takeaways and insights

Technical Elements

• MITRE ATT&CK Mapping - Framework alignment
• Detection Rules - Yara, Snort, and Sigma signatures
• Tool Analysis - Security tools and techniques used
• Evidence Documentation - Complete forensic chain of custody

Week-by-Week Breakdown

Week 0 - Tutorial Challenge

Focus: Path traversal attack and SSH key theft

• Base64 decoding challenges
• Web server log analysis
• Attack reconstruction from initial access to data exfiltration
• Remediation strategies for web application vulnerabilities

Week 1 - ProtoVault Breach

Focus: Database security and cloud infrastructure compromise

• Hardcoded credential analysis
• Git history forensics and evidence recovery
• Cloud S3 bucket security assessment
• Database breach impact analysis

Week 2 - Stealer's Shadow

Focus: Advanced persistent threat with blockchain-based malware

• Information stealer analysis and reverse engineering
• Blockchain payload delivery mechanisms
• Cloud credential compromise and lateral movement
• Advanced threat actor techniques and TTPs

Week 3 - Quantum Conundrum

Focus: Cryptographic algorithm analysis and reverse engineering

• "Quantum-proof" cipher deconstruction
• Multi-layer encryption analysis
• Seed generation and key expansion techniques
• Cryptographic implementation vulnerabilities

Week 4 - Echo Trail

Focus: Cloud security and humanitarian data breach

• Azure MFA bypass techniques
• Cloud lateral movement via Azure Arc
• NGO data breach impact assessment
• Cloud security architecture review

Week 5 - Emerald Anomaly

Focus: Supply chain attack and code obfuscation

• Typosquatting and package poisoning
• Code obfuscation and deobfuscation techniques
• PowerShell-based credential harvesting
• Supply chain security controls

Week 6 - Nullform Vault

Focus: Advanced malware analysis and reverse engineering

• Multi-layer obfuscation and anti-debugging
• ICMP reconnaissance and HTTP exfiltration
• Living-off-the-land techniques
• Advanced malware detection and response

Week 7 - Codex Circuit

Focus: Collaboration tool security and insider threats

• Slack data exfiltration analysis
• Network packet forensics (234K+ packets)
• Insider threat behavioral analysis
• Collaboration tool security controls

Week 8 - Last Ascent

Focus: ICS/SCADA security and critical infrastructure protection

• Wind turbine control system analysis
• Multi-stage attack chain reconstruction
• Industrial protocol security (Modbus TCP)
• Critical infrastructure incident response

Investigation Methodology

Standard Approach Applied Across All Challenges

1. Initial Triage - Quick assessment of available evidence
2. Evidence Collection - Systematic gathering of all artifacts
3. Technical Analysis - Deep dive into technical components
4. Timeline Reconstruction - Building complete chronology
5. Impact Assessment - Evaluating scope and severity
6. Remediation Strategy - Developing actionable fixes
7. Documentation - Comprehensive reporting and knowledge sharing

Tools and Techniques Used

Forensic Tools:

• Wireshark for network packet analysis
• Volatility for memory forensics
• Autopsy for disk forensics
• Strings and hex editors for binary analysis

Reverse Engineering:

• IDA Pro for disassembly
• Ghidra for static analysis
• x64dbg for dynamic debugging
• Python scripts for automation

Network Analysis:

• Scapy for packet manipulation
• tcpdump for traffic capture
• NetFlow analysis for pattern detection
• DNS analysis for infrastructure mapping

Malware Analysis:

• Yara for pattern matching
• VirusTotal for threat intelligence
• Cuckoo Sandbox for behavioral analysis
• PEStudio for Windows malware analysis

Key Learning Outcomes

Technical Skills Developed

• Digital Forensics - Evidence collection, preservation, and analysis
• Malware Analysis - Static and dynamic analysis techniques
• Network Security - Packet analysis and intrusion detection
• Cloud Security - AWS, Azure, and GCP security assessment
• Cryptography - Algorithm analysis and implementation review
• Industrial Security - ICS/SCADA protocol analysis and protection

Strategic Security Insights

• Defense in Depth - Multi-layered security architecture importance
• Threat Intelligence - Understanding attacker methodologies and TTPs
• Incident Response - Rapid detection, containment, and recovery
• Risk Management - Business impact assessment and prioritization
• Security Architecture - Designing resilient security controls

Professional Development

• Report Writing - Technical documentation and executive communication
• Investigation Planning - Structured approach to complex security challenges
• Evidence Handling - Proper chain of custody and forensic procedures
• Cross-functional Collaboration - Working with technical and non-technical stakeholders

Usage Guidelines

For Learning and Study

1. Read Chronologically - Progress through weeks in order to build skills progressively
2. Study Methodology - Pay attention to investigation approach and structure
3. Practice Techniques - Reproduce the analysis methods described
4. Expand Knowledge - Use references to explore topics in greater depth

For Reference and Research

1. Search by Topic - Use the structure to find specific security domains
2. Extract Techniques - Adapt investigation methods for your own use cases
3. Compare Approaches - Analyze different strategies for similar problems
4. Stay Current - Note how techniques evolve across different challenge types

Contributing and Sharing

These writeups represent comprehensive security investigations that can serve as:

• Learning Resources - For cybersecurity students and professionals
• Reference Material - For incident responders and security analysts
• Training Examples - For security team development and education
• Methodology Templates - For structuring security investigations

Disclaimer

These writeups are educational in nature and represent analysis of controlled challenge environments. All techniques described should only be applied to authorized systems and for legitimate security purposes.

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Author: Regaan
Challenge Platform: OffSec Echo Response
Completion Date: November 2025
Total Writeups: 8 comprehensive investigations