The files to suit your needs.Fixes a crash when using "po" and "expr" LLDB commands in the debugger panel, Fixes an issue when searching numbers after another case insensitive search has been performed, Fixes a few issues in the Python API with thumb/ARM identification methods. Setting it up is as easy as copying the example CMake configuration and renaming Way to modify and manipulate the ELF format. I’ve decided to use the LIEF library, as that was the easiest ![]() However… The Pain, Self-Harm and Horribly Documented Library C++, on the other hand, can link all your dependencies staticallyĪnd deployment should go smoothly. Python is great for PoC scripts, not so much for deployment. search ( ' \x85\xC0\x0F\x84 ' )): if abs ( adr3 - addr ) <= 50 : adr4 = addr + 2 break print 'Location 2 verified as:', hex ( adr4 ) print 'Target location as: ', hex ( tgt1 ) print 'Patching.' e. group ( 1 ), 16 ) if abs ( adr2 - tmp ) <= 230 : adr3 = addr tgt1 = tmp break print 'Location 1 verified as:', hex ( adr3 ) for addr in list ( e. I ) if res is not None : tmp = int ( res. group ( 1 ), 16 ) if tmp + addr + 7 = sig2 : adr2 = addr break print 'Signature 2 XREF at: ', hex ( adr2 ) for addr in list ( e. group ( 1 ), 16 ) break print 'CheckLicense() call to:', hex ( adr1 ) for addr in list ( e. search ( 'Personal License \n Registered to %1 \n %2 ' )) adr1 = 0 adr2 = 0 adr3 = 0 adr4 = 0 tgt1 = 0 print 'Signature 1 located at:', hex ( sig1 ) print 'Signature 2 located at:', hex ( sig2 ) for addr in list ( e. remove ( file_loc + '.bak' ) print 'Creating backup.' copyfile ( file_loc, file_loc + '.bak' ) e = ELF ( file_loc + '.bak' ) sig1 = list ( e. exists ( file_loc + '.bak' ): print 'Restoring from backup.' copyfile ( file_loc + '.bak', file_loc ) os. The encoded instruction is as follows:įrom pwn import * from shutil import copyfile import re, os, sys file_loc = '/opt/hopper-v3/Hopper' #file_loc = '/opt/hopper-v4/bin/Hopper' # Restore backup file if exists print file_loc if os. The specific signature that is guaranteed to be unique and present would be the mov esi, 1B7740h instruction as it’s logical toĪssume that no other parts of the program contain it. Moreover, the call to CheckLicense several instructions prior is conveniently located as we can filter all matches by proximity to the timerĬode. The timer is initiated! This means that we can reliably use the start timer code as a signature and a way to locate a call to CheckLicense. Where 1800000 milliseconds is 30 minutes… Wait… The free version of Hopper has a 30-minute session limit and we just found when What’s even more interesting is that the value 0x1B7740 stored into esi is 1800000 in decimal. text : 0x00000000638057 call _ZN7QObject10startTimerEiN2Qt9TimerTypeE QObject::startTimer(int,Qt::TimerType). ![]() Let’s begin by writing the python script: Fortunately, pwntools is well documented unlike some other libraries we’llĮncounter soon. This will allow us to rapidly prototype and test various signatures I’ve set up a virtualenv for Python 2.7 and Steps to Success Getting it to work first The tricky thing’s that we must find the right jump instructions and targets before On a more technical side, this patcher will attempt to find certain signatures presentĪround the critical points of code we want to modify. Here, we’llĬreate a patch based on the methods explained in Part 1. If you haven’t already, read Part 1 first. Prohibited, however, reverse engineering rights are protected by the French copyright laws. Note the license agreement (EULA) states that modification of the software is strictly This article is for educational purposes only.
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