Apktool VS gef

App tampering and repackaging can be performed by using reverse engineering or tampering tools, such as Apktool, dex2jar, etc.

Apktool made by iBotPeaches, this uses v2.9.1

Can someone clarify what "PP tools" are, and provide a link to them? I came across this link (https://apktool.org/) but I'm not sure if it's the right tool.

Apktool is all you need most of the time.

But it'll still be editable and we can make something good out of it. One of the famous ones, that I'm planning to use is ApkTool(https://ibotpeaches.github.io/Apktool/).

I did a dissection of twitter apk (got from apk pure) with apktool, and I found permission :

Not sure. I started reverse engineering Java apps very early in my life — initially it was J2ME games. Decompilers of the time sucked but that didn't stop me from modding Gravity Defied :P

I honestly don't know what's a good way of getting started on reverse engineering. There's a bunch of everything about Windows executables in particular, including "crackmes", but native machine code is a level up from JVM bytecode. Java classes and Android dex files can be decompiled back to sensible source with a good chance that you get something that can be compiled again. No such luck for native code — C/C++ compilation is a lossy process by its nature, especially the optimizations. Ghidra does a decent job but still requires a non-zero amount of manual assistance. Flash games also were good to hone one's reverse engineering skills since ActionScript decompilers did a pretty darn good job.

Anyway. To decompile dex to Java source, there's jadx: https://github.com/skylot/jadx

Since decompilation is sometimes lossy, there's apktool for when you want to put the app back together after tinkering with it: https://github.com/iBotPeaches/Apktool

It goes without saying that you also need a JDK and the Android SDK. In particular, you need apksigner form the SDK to sign the unsigned apks generated by apktool. You can also automate things a bit and use adb to deploy them to your device.

What I usually do is get a high-level overview of the app in jadx, and then modify the smali (dalvik bytecode in text form, very assembly-like) files generated by apktool.

I am not game or android app dev, but you might first need to de-compile apk using tools like https://ibotpeaches.github.io/Apktool/

There is also GEF, which is widely used by the reverse engineering and CTF community.

https://github.com/hugsy/gef

If you are on Linux, install GEF and be happy.

If you are in linux, I recomend none of them (haha) because you should get more used to GDB a little bit. You just need to install some good visualizers likes GEF, for example.

https://github.com/hugsy/gef, https://hugsy.github.io/gef/, https://hugsy.github.io/gef/commands/context/ ("Values in red indicate that this register has had its value changed since the last time execution stopped.")

The attached debugger is not just raw GDB but is using https://hugsy.github.io/gef/ to make debugging less of a pain. It's still not perfect but helps plenty already.

I still struggle with GDB but my excuse is that I seldom use it.

When I was studying reverse engineering though, I came across a really cool kit (which I've yet to find an alternative for lldb, which would be nice given: rust)

I'd recommend checking it out, if for no other reason than it makes a lot of things really obvious (like watching what value lives in which register).

https://github.com/hugsy/gef

LLDB's closest alternative to this is called Venom, but it's not the same at all. https://github.com/ovh/venom