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Malware obfuscation

Malware obfuscation definition

Malware obfuscation is the practice of modifying malicious software (malware) to make it more difficult for cybersecurity measures to identify. Malware obfuscation transforms the structure, logic, and appearance of the malware without affecting its core functionality.

See also: cyberattack, obfuscation, steganography, heuristic analysis, anti-malware, polymorphic malware

Common malware obfuscation methods

  • Code obfuscation modifies the actual code of the malware to make it harder to understand. Code obfuscation may involve renaming variables to be non-descriptive, inserting irrelevant code snippets, or using compression to hide the code.
  • Control flow obfuscation makes the flow of execution in the malware more convoluted to confuse analysis tools. Control flow obfuscation may be accomplished using redundant loops, jumps, or conditional statements.
  • Data obfuscation hides critical malware data using string encryption, custom data encoding, or data fragmentation.
  • Anti-analysis techniques (such as automatic detection of sandboxed environments or debugging tools) make it hard to examine the malware in a controlled environment, preventing cybersecurity professionals from working on an effective cure.
  • Polymorphism and metamorphism dynamically modifies the structure and appearance of the malware during each infection instance. Polymorphic malware generates unique variants with different signatures, while metamorphic malware actively changes its own code structure to evade signature-based detection methods.
  • Steganography involves hiding the malware within benign-looking images, documents, or other media to make the infection blend in with legitimate files.