Flag: Tornado! Hurricane!


Packer Name Packer Author Classification Analysis By Last Updated
ASPack 2.12 Alexey Solodovnikov Compressor quig June 15 2005
Allocation Anti-Debug Anti-Disassembly Section Name Sample
PE Header no yes aspack N/A
Notes
This is an easy one to find the OEP of.

Single step through a couple of opcode tricks and into the main unpack loop. You should notice a JNZ to a *very* distant address.

This distant address turns out to be the end of the packer.

Transfer Command
push [patched value]
ret
Entry Point Signature
.aspack:00412001                 public start
.aspack:00412001 start           proc near
.aspack:00412001                 pusha
.aspack:00412002                 call    skipBytes
.aspack:00412002 ; ---------------------------------------------------------------------------
.aspack:00412007                 db 0E9h
.aspack:00412008 ; ---------------------------------------------------------------------------
.aspack:00412008                 jmp     short loc_41200E ; ret address
.aspack:0041200A ; ---------------------------------------------------------------------------
.aspack:0041200A
.aspack:0041200A skipBytes:                              ; CODE XREF: start+1p
.aspack:0041200A                 pop     ebp             ; = fx ret addr after call (412007)
.aspack:0041200B                 inc     ebp
.aspack:0041200C                 push    ebp
.aspack:0041200D                 retn
.aspack:0041200D start           endp ; sp = -20h
.aspack:0041200D

.aspack:0041200E
.aspack:0041200E loc_41200E:                             ; CODE XREF: start+7j
.aspack:0041200E                 call    loc_412014
.aspack:0041200E ; ---------------------------------------------------------------------------
.aspack:00412013                 db 0EBh
.aspack:00412014 ; ---------------------------------------------------------------------------
.aspack:00412014
.aspack:00412014 loc_412014:                             ; CODE XREF: .aspack:loc_41200Ep
.aspack:00412014                 pop     ebp
.aspack:00412015                 mov     ebx, 0FFFFFFEDh
.aspack:0041201A                 add     ebx, ebp
.aspack:0041201C                 sub     ebx, 12000h
.aspack:00412022                 cmp     dword ptr [ebp+422h], 0
.aspack:00412029                 mov     [ebp+422h], ebx
.aspack:0041202F                 jnz     END_OF_PACKER

.aspack:0041239A END_OF_PACKER:                          

.aspack:0041239A                                         
.aspack:0041239A                 mov     eax, 0A870h     ; original entry point offset
.aspack:0041239F                 push    eax
.aspack:004123A0                 add     eax, [ebp+422h] ;add image base to offset
.aspack:004123A6                 pop     ecx
.aspack:004123A7                 or      ecx, ecx
.aspack:004123A9                 mov     [ebp+3A8h], eax ;patch 004123BA to be push [offset]
.aspack:004123AF                 popa
.aspack:004123B0                 jnz     short loc_4123BA
.aspack:004123B2                 mov     eax, 1
.aspack:004123B7                 retn    0Ch             ; error exit ?
.aspack:004123BA ; ---------------------------------------------------------------------------
.aspack:004123BA
.aspack:004123BA loc_4123BA:                             ; CODE XREF: .aspack:004123B0j
.aspack:004123BA                 push    0               ; put a ret addr on stack 
.aspack:004123BF                 retn                    ; ret to pushed address 



Known Unpackers
// Script for OllyScript plugin by SHaG - http://ollyscript.apsvans.com
/* 
Find target's OEP [ ASPack v2.12 ] v0.1
---------------------------------------
Author: DeAtH HaS cOMe #eCh!2004 .:[ CracksLatinos ]:.
Email : [email protected] 
OS : Win XP SP1,OllyDbg 1.10,OllyScript v0.92 
Date : 09.10.2004 
Config: No BreakPoint sets
Note : Any bug or comments, please report at [email protected]
That's all folks!
Un saludo para todo CracksLatinoS, maravillosos listeros, y para mi enana Aur

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