Android.Hook框架xposed篇(Http流量监控) – 瘦蛟舞

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所属分类：WooYun-Drops

http://drops.wooyun.org/tips/7488

官方教程:https://github.com/rovo89/XposedBridge/wiki/Development-tutorial

官网:http://repo.xposed.info/module/de.robv.android.xposed.installer

apk:http://dl-xda.xposed.info/modules/de.robv.android.xposed.installer_v33_36570c.apk

源码:https://github.com/rovo89/XposedInstaller

模块基本开发流程

1.创建工程android4.0.3(api15,测试发现其他版本也可以),可以不用activity

2.修改AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="de.robv.android.xposed.mods.tutorial"
    android:versionCode="1"
    android:versionName="1.0" >
    <uses-sdk android:minSdkVersion="15" />
    <application
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name" >
        <meta-data
            android:name="xposedmodule"
            android:value="true" />
        <meta-data
            android:name="xposeddescription"
            android:value="Easy example" />
        <meta-data
            android:name="xposedminversion"
            android:value="54" />
    </application>
</manifest>

3.在工程目录下新建一个lib文件夹,将下载好的XposedBridgeApi-54.jar包放入其中.

eclipse 在工程里选中XposedBridgeApi-54.jar 右键–Build Path–Add to Build Path.

IDEA 鼠标右键点击工程,选择Open Module Settings,在弹出的窗口中打开Dependencies选项卡.把XposedBridgeApi这个jar包后面的Scope属性改成provided.

4.模块实现接口

#!java
package de.robv.android.xposed.mods.tutorial;

import de.robv.android.xposed.IXposedHookLoadPackage;
import de.robv.android.xposed.XposedBridge;
import de.robv.android.xposed.callbacks.XC_LoadPackage.LoadPackageParam;

public class Tutorial implements IXposedHookLoadPackage {
    public void handleLoadPackage(final LoadPackageParam lpparam) throws Throwable {
        XposedBridge.log("Loaded app: " + lpparam.packageName);
    }
}

5.入口assets/xposed_init配置,声明需要加载到 XposedInstaller 的入口类:

#!java
de.robv.android.xposed.mods.tutorial.Tutorial  //完整类名:包名+类名

6.定位要hook的api

反编译目标程序,查看Smali代码
直接在AOSP(android源码)中查看

7.XposedBridge to hook it

指定要 hook 的包名
判断当前加载的包是否是指定的包
指定要 hook 的方法名
实现beforeHookedMethod方法和afterHookedMethod方法

示例如下:

#!java
package de.robv.android.xposed.mods.tutorial;

import static de.robv.android.xposed.XposedHelpers.findAndHookMethod; import de.robv.android.xposed.IXposedHookLoadPackage; import de.robv.android.xposed.XC\_MethodHook; import de.robv.android.xposed.callbacks.XC\_LoadPackage.LoadPackageParam;

public class Tutorial implements IXposedHookLoadPackage { public void handleLoadPackage(final LoadPackageParam lpparam) throws Throwable { if (!lpparam.packageName.equals("com.android.systemui")) return;

        findAndHookMethod("com.android.systemui.statusbar.policy.Clock", lpparam.classLoader, "updateClock", new XC_MethodHook() {
            @Override
            protected void beforeHookedMethod(MethodHookParam param) throws Throwable {
                // this will be called before the clock was updated by the original method
            }
            @Override
            protected void afterHookedMethod(MethodHookParam param) throws Throwable {
                // this will be called after the clock was updated by the original method
            }
    });
    }


}

重写XC_MethodHook的两个方法beforeHookedMethod和afterHookedMethod，这两个方法会在原始的方法的之前和之后执行.您可以使用beforeHookedMethod 方法来打印/篡改方法调用的参数(通过param.args) ,甚至阻止调用原来的方法（发送自己的结果）.afterHookedMethod 方法可以用来做基于原始方法的结果的事情.您还可以用它来操纵结果 .当然，你可以添加自己的代码,它将会准确地在原始方法的前或后执行.

关键API

IXposedHookLoadPackage

handleLoadPackage : 这个方法用于在加载应用程序的包的时候执行用户的操作

调用示例

#!java
public class XposedInterface implements IXposedHookLoadPackage {
public void handleLoadPackage(final LoadPackageParam lpparam) throws Throwable {
XposedBridge.log("Kevin-Loaded app: " + lpparam.packageName); }
}

参数说明|final LoadPackageParam lpparam 这个参数包含了加载的应用程序的一些基本信息。

XposedHelpers

findAndHookMethod ;这是一个辅助方法,可以通过如下方式静态导入:

#!java
import static de.robv.android.xposed.XposedHelpers.findAndHookMethod;

使用示例

#!java
findAndHookMethod("com.android.systemui.statusbar.policy.Clock", lpparam.classLoader, "handleUpdateClock", new XC_MethodHook() {
@Override
protected void beforeHookedMethod(MethodHookParam param) throws Throwable {
// this will be called before the clock was updated by the original method }
@Override
protected void afterHookedMethod(MethodHookParam param) throws Throwable {
// this will be called after the clock was updated by the original method }
});

参数说明

findAndHookMethod(Class<?>clazz, //需要Hook的类名
ClassLoader, //类加载器,可以设置为 null 
String methodName, //需要 Hook 的方法名 
Object... parameterTypesAndCallback

该函数的最后一个参数集,包含了:

(1)Hook 的目标方法的参数,譬如:

"com.android.internal.policy.impl.PhoneWindow.DecorView"

是方法的参数的类。

(2)回调方法:

a.XC_MethodHook 
b.XC_MethodReplacement

模块开发中的一些细节

1.Dalvik 孵化器 Zygote (Android系统中，所有的应用程序进程以及系统服务进程SystemServer都是由Zygote进程孕育/fork出来的)进程对应的程序是/system/bin/app_process. Xposed 框架中真正起作用的是对方法的 hook。

#!java

因为 Xposed 工作原理是在/system/bin 目录下替换文件,在 install 的时候需要 root 权限,但是运行时不需要 root 权限。

2.log 统一管理,tag 显示包名

#!java

    Log.d(MYTAG+lpparam.packageName, "hello" + lpparam.packageName);

3.植入广播接收器,动态执行指令

#!java

        findAndHookMethod("android.app.Application", lpparam.classLoader, "onCreate", new XC_MethodHook() {
            @Override
            protected void beforeHookedMethod(MethodHookParam param) throws Throwable {

                Context context = (Context) param.thisObject;
                IntentFilter filter = new IntentFilter(myCast.myAction);
                filter.addAction(myCast.myCmd);
                context.registerReceiver(new myCast(), filter);

            }

            @Override
            protected void afterHookedMethod(MethodHookParam param) throws Throwable {
                super.afterHookedMethod(param);
            }
        });

4.context 获取

#!java

    fristApplication = (Application) param.thisObject;

5.注入点选择 application oncreate 程序真正启动函数而是 MainActivity 的 onCreate (该类有可能被重写,所以通过反射得到 oncreate 方法)

#!java

    String appClassName = this.getAppInfo().className;
            if (appClassName == null) {
                Method hookOncreateMethod = null;
                try {
                    hookOncreateMethod = Application.class.getDeclaredMethod("onCreate", new Class[] {});
                } catch (NoSuchMethodException e) {
                    e.printStackTrace();
                }
                hookhelper.hookMethod(hookOncreateMethod, new ApplicationOnCreateHook());

6.排除系统 app,排除自身,确定主线程

#!java

    if(lpparam.appInfo == null || 
                    (lpparam.appInfo.flags & (ApplicationInfo.FLAG_SYSTEM | ApplicationInfo.FLAG_UPDATED_SYSTEM_APP)) !=0){
                return;
            }else if(lpparam.isFirstApplication && !ZJDROID_PACKAGENAME.equals(lpparam.packageName)){

7.hook method

#!java

    Only methods and constructors can be hooked,Cannot hook interfaces,Cannot hook abstract methods
    只能 hook 方法和构造方法,不能 hook 接口和抽象方法
    抽象类中的非抽象方法是可以 hook的, 接口中的方法不能 hook (接口中的method默认是public abstract 抽象的.field 必须是public static final)

8.参数中有自定义类

#!java

    public void myMethod (String a, MyClass b) 


通过反射得到自定义类,也可以用[xposedhelpers](https://github.com/rovo89/XposedBridge/wiki/Helpers#class-xposedhelpers)封装好的方法findMethod/findConstructor/callStaticMethod....

9.注入后反射自定义类

#!java

    Class<?> hookMessageListenerClass = null;

    hookMessageListenerClass = lpparam.classLoader.loadClass("org.jivesoftware.smack.MessageListener");

    findAndHookMethod("org.jivesoftware.smack.ChatManager", lpparam.classLoader, "createChat", String.class , hookMessageListenerClass ,new XC_MethodHook() {
        @Override
        protected void beforeHookedMethod(MethodHookParam param) throws Throwable {

            String sendTo = (String) param.args[0];
            Log.i(tag , "sendTo : + " + sendTo );

        }

        @Override
        protected void afterHookedMethod(MethodHookParam param) throws Throwable {
            super.afterHookedMethod(param);
        }
    });

10.hook 一个类的方法,该类是子类并且没有重写父类的方法,此时应该 hook 父类还是子类.(hook 父类方法后,子类若没重写,一样生效.子类重写方法需要另外 hook) (如果子类重写父类方法时候加上 spuer ,hook 父类依旧有效)

例如 java.net.HttpURLConnection extends URLConnection ,

方法在父类

#!java

    public OutputStream getOutputStream() throws IOException {
           throw new UnknownServiceException("protocol doesn't support output");
       }


org.apache.http.impl.client.AbstractHttpClient extends CloseableHttpClient ,

方法在父类(注意,android的继承的 AbstractHttpClient implements org.apache.http.client.HttpClient)

#!java

    public CloseableHttpResponse execute(
            final HttpHost target,
            final HttpRequest request,
            final HttpContext context) throws IOException, ClientProtocolException {
        return doExecute(target, request, context);
    }


android.async.http复写HttpGet导致zjdroid hook org.apache.http.impl.client.AbstractHttpClient execute 无法获取到请求 url和method

11.hook 构造方法

#!java

    public static XC_MethodHook.Unhook findAndHookConstructor(String className, ClassLoader classLoader, Object... parameterTypesAndCallback) {
        return findAndHookConstructor(findClass(className, classLoader), parameterTypesAndCallback);
    }

12.承接4,application 的onCreate 方法被重写,例如阿里的壳,重写为原生 native 方法.

解1:通过反射到 application 类重写后的 onCreate 方法再对该方法进行hook

解2:hook 构造方法(构造方法被重写,继续解1)

13.native 方法可以 hook,不过是在 java 层调用时hook而不是 hook 动态链接库.

实战Hook android 中可能的出现 HTTP 请求

首先确定http 请求的 api,大致分为:

apache 提供的 HttpClient
- 1) 创建 HttpClient 以及 GetMethod / PostMethod， HttpRequest等对象;
- 2) 设置连接参数;
- 3) 执行 HTTP 操作;
- 4) 处理服务器返回结果.
java 提供的 HttpURLConnection
- 1) 创建 URL 以及 URLConnection / HttpURLConnection 对象
- 2) 设置连接参数
- 3) 连接到服务器
- 4) 向服务器写数据
- 5) 从服务器读取数据
android 提供的 webview
第三方库:volley/android-async-http/xutils (本质是对前两种的方式的延伸,方法的重写可能对接下来的 hook 产生影响)

不太了解 java 的 hook 前可以先看下基础的代码HttpClient以及HttpURLConnection的基本使用

对 HttpClient的 hook 可以参考贾志军大牛的Zjdroid

#!java
    Method executeRequest = RefInvoke.findMethodExact("org.apache.http.impl.client.AbstractHttpClient", ClassLoader.getSystemClassLoader(),
            "execute", HttpHost.class, HttpRequest.class, HttpContext.class);

    hookhelper.hookMethod(executeRequest, new AbstractBahaviorHookCallBack() {
        @Override
        public void descParam(HookParam param) {
            // TODO Auto-generated method stub
            Logger.log_behavior("Apache Connect to URL ->");
            HttpHost host = (HttpHost) param.args[0];

            HttpRequest request = (HttpRequest) param.args[1];
            if (request instanceof org.apache.http.client.methods.HttpGet) {
                org.apache.http.client.methods.HttpGet httpGet = (org.apache.http.client.methods.HttpGet) request;
                Logger.log_behavior("HTTP Method : " + httpGet.getMethod());
                Logger.log_behavior("HTTP GET URL : " + httpGet.getURI().toString());
                Header[] headers = request.getAllHeaders();
                if (headers != null) {
                    for (int i = 0; i < headers.length; i++) {
                        Logger.log_behavior(headers[i].getName() + ":" + headers[i].getName());
                    }
                }
            } else if (request instanceof HttpPost) {
                HttpPost httpPost = (HttpPost) request;
                Logger.log_behavior("HTTP Method : " + httpPost.getMethod());
                Logger.log_behavior("HTTP URL : " + httpPost.getURI().toString());
                Header[] headers = request.getAllHeaders();
                if (headers != null) {
                    for (int i = 0; i < headers.length; i++) {
                        Logger.log_behavior(headers[i].getName() + ":" + headers[i].getValue());
                    }
                }
                HttpEntity entity = httpPost.getEntity();
                String contentType = null;
                if (entity.getContentType() != null) {
                    contentType = entity.getContentType().getValue();
                    if (URLEncodedUtils.CONTENT_TYPE.equals(contentType)) {

                        try {
                            byte[] data = new byte[(int) entity.getContentLength()];
                            entity.getContent().read(data);
                            String content = new String(data, HTTP.DEFAULT_CONTENT_CHARSET);
                            Logger.log_behavior("HTTP POST Content : " + content);
                        } catch (IllegalStateException e) {
                            // TODO Auto-generated catch block
                            e.printStackTrace();
                        } catch (IOException e) {
                            // TODO Auto-generated catch block
                            e.printStackTrace();
                        }

                    } else if (contentType.startsWith(HTTP.DEFAULT_CONTENT_TYPE)) {
                        try {
                            byte[] data = new byte[(int) entity.getContentLength()];
                            entity.getContent().read(data);
                            String content = new String(data, contentType.substring(contentType.lastIndexOf("=") + 1));
                            Logger.log_behavior("HTTP POST Content : " + content);
                        } catch (IllegalStateException e) {
                            // TODO Auto-generated catch block
                            e.printStackTrace();
                        } catch (IOException e) {
                            // TODO Auto-generated catch block
                            e.printStackTrace();
                        }

                    }
                }else{
                    byte[] data = new byte[(int) entity.getContentLength()];
                    try {
                        entity.getContent().read(data);
                        String content = new String(data, HTTP.DEFAULT_CONTENT_CHARSET);
                        Logger.log_behavior("HTTP POST Content : " + content);
                    } catch (IllegalStateException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    } catch (IOException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }

                }

            }
        }

        @Override
        public void afterHookedMethod(HookParam param) {
            // TODO Auto-generated method stub
            super.afterHookedMethod(param);
            HttpResponse resp = (HttpResponse) param.getResult();
            if (resp != null) {
                Logger.log_behavior("Status Code = " + resp.getStatusLine().getStatusCode());
                Header[] headers = resp.getAllHeaders();
                if (headers != null) {
                    for (int i = 0; i < headers.length; i++) {
                        Logger.log_behavior(headers[i].getName() + ":" + headers[i].getValue());
                    }
                }

            }
        }
    });

对 HttpURLConnection 的 hook Zjdroid 未能提供完美的解决方案,想要取得除了 URL 之外的 data 字段必须对I/O流操作.

#!java
    Method openConnectionMethod = RefInvoke.findMethodExact("java.net.URL", ClassLoader.getSystemClassLoader(), "openConnection");
    hookhelper.hookMethod(openConnectionMethod, new AbstractBahaviorHookCallBack() {
        @Override
        public void descParam(HookParam param) {
            // TODO Auto-generated method stub
            URL url = (URL) param.thisObject;
            Logger.log_behavior("Connect to URL ->");
            Logger.log_behavior("The URL = " + url.toString());
        }
    });

我采取的临时解决方法是对I/O 进行正则匹配,类似 url 的 data 字段就打印出来,代码如下(这段代码只能解决前文 HttpUtils而且会有误报,大家有啥好想法欢迎指点一二)

#!java
    findAndHookMethod("java.io.PrintWriter", lpparam.classLoader, "print",String.class, new XC_MethodHook() {
        @Override
        protected void beforeHookedMethod(MethodHookParam param) throws Throwable {
            String print = (String) param.args[0];
            Pattern pattern = Pattern.compile("(\\w+=.*)");
            Matcher matcher = pattern.matcher(print);
            if (matcher.matches())
                Log.i(tag+lpparam.packageName,"data : " + print);
            //Log.d(tag,"A :" + print);
        }

    });

因为Android-async-http重写了 HttpGet 导致 Zjdroidhook 失败(未进入 HttpGet 和 HttpPost 的判读),加入一个else 语句就可以解决这个问题

#!java
else {
                    HttpEntityEnclosingRequestBase httpGet = (HttpEntityEnclosingRequestBase) request;
                    HttpEntity entity = httpGet.getEntity();
                    Logger.log_behavior("HttpRequestBase URL : " + httpGet.getURI().toString());
                    Header[] headers = request.getAllHeaders();
                    if (headers != null) {
                        for (int i = 0; i < headers.length; i++) {
                            Logger.log_behavior(headers[i].getName() + ":" + headers[i].getName());
                        }
                    }

                    if(entity!= null){
                                try {
                                    String content = EntityUtils
                                            .toString(entity);
                                    Logger.log_behavior("HTTP entity Content : "
                                            + content);
                                } catch (IllegalStateException e) {
                                    // TODO Auto-generated catch block
                                    e.printStackTrace();
                                } catch (IOException e) {
                                    // TODO Auto-generated catch block
                                    e.printStackTrace();
                                }
                    }

                    }

一些常用工具

zjdroid:脱壳/api监控
justTrustMe:忽略证书效验
IntentMonitor:可以监控显/隐意图 intent
Xinstaller:设置应用/设备属性...
XPrivacy:权限管理

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模块基本开发流程

关键API

模块开发中的一些细节

实战Hook android 中可能的出现 HTTP 请求

一些常用工具

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