Is it possible to modify application inner function, for instance browser...

[KnIfER]

Yesterday I've learned how to intercept and modify windows system calls from certain application.

Now I wonder is it possible to modify inner functions of app ?

For instance the chrome browser have many limitations, some page can't be shown inside of a iframe, is it possible to unleash that hard-coded limitation, if I've found the source code?

what tool do I need, Frida?

[m417z]

Yes, it's certainly possible. Just a couple of days ago, a mod was published which does something like this with Chrome: Chrome UI Tweaks.
Regarding tools, I like using x64dbg, but other tools like Frida or WinDbg might work too, depending on your needs and preferences.

[KnIfER]

Thanks! I will learn how to use x64dbg first.

Are there any tutorials on how to get those binary instructions used in Chrome UI Tweaks?

I found one step-by-step tutorial (in chinese) : chrome extension developer mode warning remover-CSDN . Steps are : load chrome.dll , press alt+f9 multiple times until run into that dll module, and then right-click and search for string references..

Another tutorial (which I cannot understand) : Hooking Chrome’s SSL functions – Nytro Security

But still, dont know how to locate the binary instructions of specific function .

[m417z]

There are many tutorials, it's difficult to just name one. Look for x64dbg and reverse engineering tutorials.