Android Reverse Exposure Removing Advertising Module

Hook third-party library API-using Xposed framework-taking Google Admob advertisement as an example

I. Background

When I first came into contact with the Xposed framework, I also saw an article on the blog of this platform, which was about using the Xposed framework to hijack the login interface. The link is as follows: hook technology of Xposed in Android reverse analysis. For the construction of Xposed environment, you can also refer to the above link, so I won't go into details here.

Because it uses findAndHookMethod of XposedHelpers.jar, it is troublesome to pass the parameter list of the function to Hook. Use the HookMethod of XposedBridge.jar This method can hook any API by passing in an instance of the function to be hooked, and then implementing the callback interface XC_MethodHook.

Back to the topic, to get an instance of a function, you can use the Java reflection mechanism. For the API of Android system, it is easy to get an instance of a function through reflection. However, for the third-party library API mentioned in this article, the reflection of obtaining the instance of the third-party library API will be invalid when cross-applying, and you need to find another way to obtain the instance of the third-party library API. This will be explained in detail below, taking the advertising API as an example.

Two. Category /API description

IXposedHookLoadPackage interface

Method description

HandleLoadPackage(XC _ load package. LoadPackageParam LoadPackageParam)

This method is used to perform the user's action when the package of the application is loaded.

The parameter loadPackageParam contains some basic information of the loaded application. You can use this parameter to obtain the class object of the class where the API is located, so as to obtain an instance of the API.

XposedBridge class

Method description

HookMethod (member hookMethod, XC _ method hook callback)

1. parameters: Member hookMethod is an API instance to hook, that is, a method object.

2. Callback interface: Implement the XC _ method hook interface, and rewrite the processing methods before and after hook API running (see below, for example).

XposedBridge provides many APIs to help developers hook functions, such as:

Three. Write the hook advertisement API of X exposure module

Hook the API of Google AdMob platform to limit the display of advertisements. First of all, we need to know the API used to display advertisements on the AdMob platform. By looking at the AdMob advertisement access guide, taking banner advertisement as an example, the API used to display advertisements belongs to the LOAD () class of com. Google.android.gms.ads.adview Hook this API and prohibit it from running. The concrete implementation is as follows.

Write exposed modules

Four. Operation effect

1. Logarithmic display

As a package communicator. Slam dunk game. The stream has been loaded, an instance of API loadAd has been obtained, and its operation is restricted.

Verb (abbreviation of verb) abstract

In fact, Xposed provides a rich API for developers to hook the objective function. Because this article is dedicated to hooking the functions of third-party libraries, only some related APIs are mentioned. When obtaining the third-party library class, the parameter loadPackageParam should be used, so the interface IXposedHookLoadPackage should be implemented. Although this paper only briefly mentions the hook of the function of the third-party advertising library, it can be extended to the general third-party library and can provide reference.