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Reverse Engineering

Reverse engineering is understanding how something works when you don't have the source code
It's a core skill for malware analysis , vulnerability research , exploit development , and understanding proprietary protocols

Why Reverse Engineering Matters

  • Malware analysis requires understanding what a binary does without source
  • Vulnerability research needs to find bugs in compiled code
  • Protocol reversing enables interoperability testing
  • Competitor analysis (within legal bounds)
  • Legacy code maintenance when source is unavailable
  • Firmware analysis for IoT security testing

The RE Mindset

  • Every observation is a hypothesis that needs verification
  • Multiple analysis methods converge on truth
  • Static analysis tells you what the code could do
  • Dynamic analysis tells you what the code actually does
  • Documentation is created not found

Analysis Approaches

Static Analysis - Examining code without executing it * Disassembly (assembly instructions) * Decompilation (higher-level representation) * String extraction * Import/export analysis * Structure analysis

Dynamic Analysis - Examining code during execution * Debugger stepping * System call tracing * Network monitoring * Memory inspection * API hooking

Common Targets

  • Malware - Understand behavior, C2, persistence
  • Binaries - Find vulnerabilities (buffer overflows, use-after-free)
  • Firmware - Extract filesystems, find backdoors
  • Mobile Apps - API endpoints, crypto schemes, hardcoded keys
  • Protocols - Reverse engineer proprietary protocols
  • Drivers - Kernel-level vulnerability research

Legal and Ethical Boundaries

  • Only reverse engineer software you own or have permission to analyze
  • Malware analysis in isolated environments only
  • Vulnerability disclosure follows responsible disclosure process
  • DMCA has anti-circumvention provisions (varies by jurisdiction)