mirror of
https://github.com/vxunderground/MalwareSourceCode.git
synced 2024-12-19 09:56:10 +00:00
175 lines
4.4 KiB
PHP
175 lines
4.4 KiB
PHP
; Catchy32 v1.6-2 - Length Disassembler Engine 32bit
|
|
; original source Catchy32.inc-orig (c) sars [HI-TECH] 2003
|
|
; this slightly opimized version - herm1t'2004
|
|
BITS 32
|
|
CPU 386
|
|
global catchy32
|
|
|
|
pref66h equ 1
|
|
pref67h equ 2
|
|
|
|
catchy32: pushad
|
|
mov esi, [esp + 36] ; pointer to opcode
|
|
sub esp, 256 ; allocate space for the table in stack
|
|
mov ebp, esp ; ebp <- opcode table
|
|
mov edi, esp
|
|
push esi
|
|
;; (1) unpack table
|
|
mov edx, esp ; save stack pointer
|
|
push 115
|
|
pop ecx
|
|
call .data
|
|
db 0x45,0x29,0x20,0x45,0x29,0x20,0x45,0x29
|
|
db 0x20,0x45,0x29,0x20,0x45,0x29,0x36,0x45
|
|
db 0x29,0x36,0x45,0x29,0x36,0x45,0x29,0x36
|
|
db 0xe0,0xe0,0x60,0x25,0x57,0x30,0x28,0x40
|
|
db 0xe7,0x27,0x2c,0x2b,0xc5,0xa0,0x31,0x40
|
|
db 0x4f,0x40,0x29,0x60,0x87,0x8f,0x2b,0x2d
|
|
db 0x25,0x2c,0x2e,0x2d,0x22,0x20,0x45,0x27
|
|
db 0x20,0x85,0x87,0x2f,0x32,0x40,0x36,0x37
|
|
db 0x20,0x25,0x60,0x65,0x33,0x40,0x35,0x34
|
|
db 0x23,0x85,0x26,0x75,0x45,0x46,0x85,0x60
|
|
db 0xb5,0xe5,0xe5,0xe5,0x65,0x4b,0x25,0x24
|
|
db 0x85,0xef,0x2f,0xe5,0x25,0x20,0x21,0x2a
|
|
db 0x25,0x20,0x21,0x2a,0xa5,0x35,0x2a,0x65
|
|
db 0x2a,0x2b,0x2a,0x80,0x34,0xe5,0xe5,0x25
|
|
db 0x34,0xc5,0x26
|
|
; xlat table
|
|
db 0x00,0x01,0x02,0x03,0x10,0x11,0x1e,0x22
|
|
db 0x23,0x28,0x31,0x33,0x39,0x40,0x60,0x88
|
|
db 0x89,0xc0,0xc2,0xe0,0xe1,0xee,0xf0,0xff
|
|
.data: pop esi
|
|
lea ebx, [esi + ecx]
|
|
xor eax, eax
|
|
.next: lodsb
|
|
push ecx
|
|
mov ecx, eax
|
|
shr ecx, 5
|
|
and al, 31
|
|
xlat
|
|
rep stosb
|
|
pop ecx
|
|
loop .next
|
|
mov esp, edx ; restore stack frame
|
|
;; /unpack
|
|
pop esi
|
|
push edi ; (2)
|
|
mov edi, esi ; (3)
|
|
|
|
cmp word [esi], 20cdh ; VXD call (6 bytes)
|
|
jne ExtFlags
|
|
inc esi
|
|
inc esi
|
|
lodsd
|
|
CalcLen: sub esi, edi ; (3)
|
|
cmp esi, 15
|
|
jbe OK
|
|
Error: xor esi, esi
|
|
dec esi
|
|
OK: pop esp ; (2)
|
|
mov [esp+4*7], esi
|
|
popad
|
|
ret
|
|
; ecx zero after loop
|
|
;==============================================================================
|
|
ExtFlags: xor eax, eax
|
|
xor ebx, ebx
|
|
cdq
|
|
lodsb ;al <- opcode
|
|
mov cl, al ;cl <- opcode
|
|
cmp al, 0fh ;Test on prefix 0Fh
|
|
jne NormTable
|
|
lodsb
|
|
inc ah ;EAX=al+100h (100h/2 - lenght first table)
|
|
NormTable: shr eax, 1 ;Elements tables on 4 bits
|
|
mov al, byte [ebp + eax]
|
|
jc IFC1
|
|
shr eax, 4 ;Get high 4-bits block if offset is odd, otherwise...
|
|
IFC1: and al, 0fh
|
|
xchg eax, ebx ;EAX will be needed for other purposes
|
|
CheckFlags: cmp bl, 0Eh ;Test on ErrorFlag
|
|
je Error
|
|
cmp bl, 0Fh ;Test on PrefixFlag
|
|
je Prefix
|
|
or ebx, ebx ;One byte command
|
|
jz CalcLen
|
|
btr ebx, 0 ;Command with ModRM byte
|
|
jc ModRM
|
|
btr ebx, 1 ;Test on imm8,rel8 etc flag
|
|
jc incr1
|
|
btr ebx, 2 ;Test on ptr16 etc flag
|
|
jc incr2
|
|
and bl, 11110111b ;Reset 16/32 sign
|
|
cmp cl, 0A0h ;Processing group 0A0h-0A3h
|
|
jb Check66h
|
|
cmp cl, 0A3h
|
|
ja Check66h
|
|
test ch, pref67h
|
|
jnz incr2
|
|
jmp incr4
|
|
Check66h: test ch, pref66h
|
|
jnz incr2
|
|
incr4: inc esi
|
|
inc esi
|
|
incr2: inc esi
|
|
incr1: inc esi
|
|
jmp_CheckFlags: jmp CheckFlags
|
|
;-----------------------------------------------
|
|
Prefix: cmp cl, 66h
|
|
je SetF66h
|
|
cmp cl, 67h
|
|
jne ExtFlags
|
|
SetF67h: or ch, pref67h
|
|
jmp ExtFlags
|
|
;-----------------------------------------------
|
|
SetF66h: or ch, pref66h
|
|
jmp ExtFlags
|
|
;-----------------------------------------------
|
|
ModRM: lodsb
|
|
cmp cl, 0F7h ;Check on 0F6h and 0F7h groups
|
|
je F6F7
|
|
cmp cl, 0F6h
|
|
jne ModXX
|
|
F6F7: test al, 00111000b ;Processing groups 0F6h and 0F7h
|
|
jnz ModXX
|
|
test cl, 00000001b
|
|
jz incbt1
|
|
test ch, 1
|
|
jnz incbt2
|
|
inc esi
|
|
inc esi
|
|
incbt2: inc esi
|
|
incbt1: inc esi
|
|
ModXX: mov edx, eax ;Processing MOD bits
|
|
and al, 00000111b ;al <- only R/M bits
|
|
test dl, 11000000b ;Check MOD bits
|
|
jz Mod00
|
|
jp CheckFlags ;Or c_Mod11
|
|
js Mod10
|
|
Mod01: test ch, pref67h
|
|
jnz incr1 ;16-bit addressing
|
|
cmp al, 4 ;Check SIB
|
|
je incr2
|
|
jmp incr1
|
|
;-----------------------------------------------
|
|
Mod00: test ch, pref67h
|
|
jz Mod00_32 ;32-bit addressing
|
|
cmp al, 6
|
|
je incr2
|
|
jmp jmp_CheckFlags
|
|
;-----------------------------------------------
|
|
Mod00_32: cmp al, 4 ;Check SIB
|
|
jne disp32
|
|
lodsb ;Processing SIB byte
|
|
and al, 00000111b
|
|
disp32: cmp al, 5
|
|
je incr4
|
|
jmp jmp_CheckFlags
|
|
;-----------------------------------------------
|
|
Mod10: test ch, pref67h
|
|
jnz incr2 ;16-bit addressing
|
|
cmp al, 4 ;Check SIB
|
|
jne incr4
|
|
inc esi
|
|
jmp incr4
|