![]() ![]() IDA Pro is a pretty awesome multi-processor disassembler and debugger. The first thing you need to do is install the demo version of IDA Pro from their website. In this article, we are going to permanently patch this check so we are always authenticated. If you remember, we had found a way to change the logic of the method that gets called when Login was tapped and hence bypassed the login authentication check. ![]() In this article, we will be using the same application GDB-Demo that we had used in Part 22 of this series. Once the binary is patched, you can then run it on a jailbroken device with the changed logic. So you don’t have to repeat the same process over and over again. Once a change has been made in the application’s binary, its permanent. This is where patching the application is useful. However, using Cycript or GDB is a bit of a pain as one has to do repeat the same process everytime after you restart the application. All of these things have been done to serve a purpose, which is to make the application do what we want. Therefore code execution from the memory page is possible even though it requires series of mistakes to make.In the previous applications we have looked at how we can hijack method implementations during runtime using Cycript, and even change the logic of the code rather than changing the complete implementation using GDB. As a consequence, the memory area has the protection flag of PAGE_EXECUTE_READWRITE. dvalloc command to allocate the memory for the data. $$ It reads binary data from the specified file and copies the data to the pre-allocated memory area.Ġ07e0090 ae c2 a3 82 b6 5f 3f 82-ae c2 a1 82 b4 5f 3f 82. Once the prompt is given it waits for command to execute.dvalloc command is used to allocate memory.readmem command is to copy the the content of the file to the allocated memory area. There is a script called LoadFile.wds that does the job so it's enough to execute this with the correct parameters. In the further steps, there is nothing to do with the application. To use Windbg as hex editor the first things that needs to be done is to open an application (say notepad.exe) to get Windbg prompt. Beyond that, I don't even miss the graphical interface. My second thought was if there was anything that I can achieve in hex editor but cannot in Windbg. It sounds very good because those commands are powerful. I was thinking about that I could use my plugin commands, and many built-in Windbg commands. In the recent days, I was thinking about what if I give it a try to tentatively use Windbg as a static hex editor. That would mean I should maintain both code base in the future which is not what I want. Although this is true, I have some plugin commands already written for Windbg, and there should not be a reason to code them again to work with some hex-editor, too. ![]() Some hex editors have plugin interface so for them it's possible to write special functionality that accounts people needs. Even though some of them have rich feature set built-in sometimes there is a need to use special functionality that goes beyond the capability of any hex editor. I often use hex editor to examine binaries. Possible risks are discussed at the end of the post. It consists of the followings: the advantage of using this approach, and the initial steps to getting started. This blog post discusses the idea to use Windbg as hex editor. ![]()
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