Assembly_101/27_advanced_polymorphic.asm at main · b4ndit23/Assembly_101 · GitHub

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; Features:
; 1. Multi-layer encryption
; 2. Random garbage instruction insertion
; 3. Register renaming
; 4. Instruction substitution
; 5. Dynamic API resolution
; 6. Anti-debugging checks

section .text
global _start

_start:
    jmp init_poly_engine

; =============================================
; Polymorphic Engine Components
; =============================================

poly_engine:
    ; Generate random seed based on timing
    rdtsc
    xor eax, [esp]          ; Mix with stack value
    mov [poly_key], eax     ; Save as base key

    ; Setup decryptor with random characteristics
    call randomize_decryptor

    ; Encrypt payload with multi-layer encryption
    call encrypt_payload

    ; Insert garbage instructions
    call insert_junk_code

    ; Add anti-debugging
    call insert_anti_debug

    jmp poly_decryptor

; =============================================
; Randomized Decryptor
; =============================================

randomize_decryptor:
    ; Randomize register usage
    call get_random
    and eax, 0x7
    mov [counter_reg], eax  ; Select random counter register

    call get_random
    and eax, 0x7
    mov [pointer_reg], eax  ; Select random pointer register

    ; Randomize decryption algorithm
    call get_random
    and eax, 0x3
    jmp [decrypt_algorithms + eax*4]

decrypt_xor:
    ; XOR decryption template
    mov [decrypt_instruction], 0x31  ; XOR opcode
    ret

decrypt_add:
    ; ADD decryption template
    mov [decrypt_instruction], 0x01  ; ADD opcode
    ret

decrypt_sub:
    ; SUB decryption template
    mov [decrypt_instruction], 0x29  ; SUB opcode
    ret

decrypt_ror:
    ; ROR decryption template
    mov [decrypt_instruction], 0xC1  ; ROR opcode
    mov [decrypt_instruction+1], 0xC0 ; ModR/M for ROR
    ret

; =============================================
; Polymorphic Decryptor (Generated at Runtime)
; =============================================

poly_decryptor:
    ; This will be dynamically constructed
    nop
    nop
    nop
    nop
    nop
    nop
    nop
    nop
    nop
    nop
    nop
    nop
    nop
    nop
    nop
    nop
    nop
    nop
    nop
    nop

; =============================================
; Multi-layer Encrypted Payload
; =============================================

encrypted_payload:
    ; This will contain the actual encrypted payload
    ; Encrypted in multiple layers that must be decrypted sequentially
    times 512 db 0

; =============================================
; Engine Helper Functions
; =============================================

get_random:
    ; Better pseudo-random number generator
    rdtsc
    xor eax, [esp]
    rol eax, 13
    add eax, [poly_key]
    ret

insert_junk_code:
    ; Insert random nops or benign instructions
    call get_random
    and eax, 0xF
    mov ecx, eax
.junk_loop:
    call get_random
    and eax, 0xFF
    mov [junk_buffer + ecx], al
    loop .junk_loop
    ret

insert_anti_debug:
    ; Insert anti-debugging tricks
    mov eax, 0x30
    mov [anti_debug_check], eax
    ret

; =============================================
; Data Section
; =============================================

section .data
poly_key dd 0
counter_reg dd 0
pointer_reg dd 0
decrypt_instruction times 4 db 0
decrypt_algorithms dd decrypt_xor, decrypt_add, decrypt_sub, decrypt_ror
junk_buffer times 16 db 0
anti_debug_check dd 0