MalwareSourceCode/MSDOS/Virus.MSDOS.Unknown.detect.asm
2021-01-12 17:38:47 -06:00

87 lines
2.7 KiB
NASM

cseg segment para public 'CODE'
assume cs:cseg,ds:cseg,es:cseg,ss:cseg
org 100h
begin: mov dx,offset virus_get ; Set Int F2h Handler
mov ax,25F2h
int 21H
mov dx,offset signon ; Tell Them We're Here
mov ah,9
int 21h
mov dx,((offset pgm_len+15)/16)+10h ; Reserve DX Paragraphs Mem
mov ax,3100h ; TSR Code 0
int 21h
virus_get proc near
sti
push ax ; Save Registers
push bx
push cx
push dx
push di
push si
push bp
push ds
push es
cmp dx, 'As' ; Virus?
jne okay ; Nope
mov ax,cs
mov ds,ax
mov dx,offset warning ; Warn User
mov ah,9
int 21h
check: mov ah,1 ; Read Keyboard
int 21h
cmp al,'C' ; User Wants To Continue
je cont
cmp al,'c'
je cont
cmp al,'Q' ; User Wants To Quit
je quit
cmp al,'q'
je quit
mov dx,offset bad ; Incorrect Key
mov ah,9
int 21h
jmp check
quit: mov ah,9 ; 'Contact Havoc The ...'
mov dx,offset ending
int 21h
mov ax,4cffh ; Exit Code 255
int 21h
cont: mov dx,offset crlf ; Send CR/LF
mov ah,9
int 21h
okay: pop es ; Restore Registers
pop ds
pop bp
pop si
pop di
pop dx
pop cx
pop bx
pop ax
iret ; Interrupt Return
virus_get endp
signon db 10,13,'Gunther Virus Detection Handler Installed.'
db 10,13,'Created by Havoc The Chaos'
db 10,13,'Copywrite (c) 1992, 1993 by John Burnette'
db 10,13,'All Rights Reserved.',10,13,'$'
warning db 7,7,7,10,13,'Warning, Interrupt F2h Detected: Gunther Virus is active!'
db 10,13,'Continue or Quit (C/Q) ? $'
ending db 10,10,13,'Contact Havoc The Chaos for a cure by sending him the virus!',7,'$'
bad db 7,7,8,' ',8,'$'
crlf db 10,13,'$'
pgm_len equ $-begin
cseg ends
end begin