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EC-Council

EC0-350 · Question #829

More sophisticated IDSs look for common shellcode signatures. But even these systems can be bypassed, by using polymorphic shellcode. This is a technique common among virus writers - it basically…

The correct answer is A. They encrypt the shellcode by XORing values over the shellcode, using loader code to decrypt the. See the full explanation below for the reasoning.

Question

More sophisticated IDSs look for common shellcode signatures. But even these systems can be bypassed, by using polymorphic shellcode. This is a technique common among virus writers - it basically hides the true nature of the shellcode in different disguises. How does a polymorphic shellcode work?

Options

  • AThey encrypt the shellcode by XORing values over the shellcode, using loader code to decrypt the
  • BThey convert the shellcode into Unicode, using loader to convert back to machine code then executing them
  • CThey reverse the working instructions into opposite order by masking the IDS signatures
  • DThey compress shellcode into normal instructions, uncompress the shellcode using loader code and then

How the community answered

(35 responses)
  • A
    83% (29)
  • B
    9% (3)
  • C
    3% (1)
  • D
    6% (2)

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