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教你如何高效的检查APK中使用敏感权限的地方以及检查某系统方法被调用的地方

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前言

相信最近在App上架应用商店的同学都感受到了,国内对用户的隐私越来越重视,如MAC地址,设备ID,IMEI信息等,要么就干脆不用,要么就必须很明显的告诉用户想要获取这些信息,相关法律及规定,参考《网络安全法》及《关于开展APP侵害用户权益专项整治工作的通知》

开门见山

废话不多说,找了几个反编译工具,并简单看了下使用方法,最终锁定androguard,官方解释:对Android应用程序的逆向工程、恶意软件和恶意软件分析,它提供了一系列的Apk以及dex、odex、arsc等文件的分析处理功能,可以轻松的帮助我们找到调用系统权限的地方。且python脚本执行,简直不能再好用了

环境

  • python

    https://www.python.org
  • pycharm

    https://www.jetbrains.com/pycharm/download/
  • androguard

    https://androguard.readthedocs.io/en/latest/

    安装

    pip install -U androguard

    如果想在命令行直接操作,请在安装完后执行如下:

    androguard analyze

    执行后如图:
    CleanShot 2021-07-15 at 17.20.24@2x.png
    然后再加载apk,在上面执行后,输入如下:

    a, d, dx = AnalyzeAPK("examples/android/abcore/app-prod-debug.apk")

    apk加载完成后就可以调用相关api来获取信息

    获取权限

    In [2]: a.get_permissions()
    Out[2]:
    ['android.permission.INTERNET',
     'android.permission.WRITE_EXTERNAL_STORAGE',
     'android.permission.ACCESS_WIFI_STATE',
     'android.permission.ACCESS_NETWORK_STATE']

    获取Activity

    In [3]: a.get_activities()
    Out[3]:
    ['com.greenaddress.abcore.MainActivity',
     'com.greenaddress.abcore.BitcoinConfEditActivity',
     'com.greenaddress.abcore.AboutActivity',
     'com.greenaddress.abcore.SettingsActivity',
     'com.greenaddress.abcore.DownloadSettingsActivity',
     'com.greenaddress.abcore.PeerActivity',
     'com.greenaddress.abcore.ProgressActivity',
     'com.greenaddress.abcore.LogActivity',
     'com.greenaddress.abcore.ConsoleActivity',
     'com.greenaddress.abcore.DownloadActivity']

    其他

    # 包名
    In [4]: a.get_package()
    Out[4]: 'com.greenaddress.abcore'
    # app名字
    In [5]: a.get_app_name()
    Out[5]: u'ABCore'
    # logo
    In [6]: a.get_app_icon()
    Out[6]: u'res/mipmap-xxxhdpi-v4/ic_launcher.png'
    # 版本号
    In [7]: a.get_androidversion_code()
    Out[7]: '2162'
    # 版本名
    In [8]: a.get_androidversion_name()
    Out[8]: '0.62'
    # 最低sdk支持
    In [9]: a.get_min_sdk_version()
    Out[9]: '21'
    # 最高
    In [10]: a.get_max_sdk_version()
    # 目标版本
    In [11]: a.get_target_sdk_version()
    Out[11]: '27'
    # 获取有效目标版本
    In [12]: a.get_effective_target_sdk_version()
    Out[12]: 27
    # manifest文件
    In [13]: a.get_android_manifest_xml()
    Out[13]: <Element manifest at 0x7f9d01587b00>

    等等吧,Api实在是太多了,还是关注官方文档吧,只有你想不到,没有它没有的,如下链接:

    https://androguard.readthedocs.io/en/latest/intro/gettingstarted.html#using-the-analysis-object

    更多demo

https://github.com/androguard/androguard/tree/master/examples

下面直接开始实践。

检索使用敏感权限的地方并输出文件

下面就是检查APK中使用敏感权限的实现,请看:

import os
import sys

# 引入androguard的路径,根据个人存放的位置而定
androguard_module_path = os.path.join(os.path.dirname(os.path.abspath(__file__)), 'androguard')
if not androguard_module_path in sys.path:
    sys.path.append(androguard_module_path)

from androguard.misc import AnalyzeAPK
from androguard.core.androconf import load_api_specific_resource_module

path = r"/apk"
out_path = r"/out"
files = []
path_list = os.listdir(path)
path_list.sort()
for name in path_list:
    if os.path.isfile(os.path.join(path, name)):
        files.append(name)


def main():
    for apkFile in files:
        file_name = os.path.splitext(apkFile)[0]
        print(apkFile)
        out = AnalyzeAPK(path + '/' + apkFile)
        # apk object 抽象apk对象,可以获取apk的一些信息,如版本号、包名、Activity等
        a = out[0]
        # DalvikVMFormat 数组,一个元素其实对应的是class.dex,可以从DEX文件中获取类、方法或字符串。
        d = out[1]
        # Analysis 分析对象,因为它包含特殊的类,这些类链接有关classes.dex的信息,甚至可以一次处理许多dex文件,所以下面我们从这里面来分析整个apk
        dx = out[2]

        # api和权限映射
        # 输出文件路径
        api_perm_filename = os.path.join(out_path, file_name + "_api-perm.txt")
        api_perm_file = open(api_perm_filename, 'w', encoding='utf-8')
        # 权限映射map
        permissionMap = load_api_specific_resource_module('api_permission_mappings')
        # 遍历apk所有方法
        for meth_analysis in dx.get_methods():
            meth = meth_analysis.get_method()
            # 获取类名、方法名
            name = meth.get_class_name() + "-" + meth.get_name() + "-" + str(
                meth.get_descriptor())
             
            for k, v in permissionMap.items():
                # 匹配系统权限方法,匹配上就输出到文件中
                if name == k:
                    result = str(meth) + ' : ' + str(v)
                    api_perm_file.write(result + '\n')
        api_perm_file.close()


if __name__ == '__main__':
    main()

输出结果

Landroid/app/Activity;->navigateUpTo(Landroid/content/Intent;)Z : ['android.permission.BROADCAST_STICKY']
Landroid/app/Activity;->onMenuItemSelected(I Landroid/view/MenuItem;)Z : ['android.permission.BROADCAST_STICKY']
Landroid/app/Activity;->setRequestedOrientation(I)V : ['android.permission.BROADCAST_STICKY']
Landroid/app/Activity;->unregisterReceiver(Landroid/content/BroadcastReceiver;)V : ['android.permission.BROADCAST_STICKY']
Landroid/os/PowerManager$WakeLock;->acquire(J)V : ['android.permission.WAKE_LOCK']
Landroid/os/PowerManager$WakeLock;->release()V : ['android.permission.WAKE_LOCK']
Landroid/location/LocationManager;->isProviderEnabled(Ljava/lang/String;)Z : ['android.permission.ACCESS_COARSE_LOCATION', 'android.permission.ACCESS_FINE_LOCATION']
Landroid/location/LocationManager;->getLastKnownLocation(Ljava/lang/String;)Landroid/location/Location; : ['android.permission.ACCESS_COARSE_LOCATION', 'android.permission.ACCESS_FINE_LOCATION']
Landroid/app/ActivityManager;->getRunningTasks(I)Ljava/util/List; : ['android.permission.GET_TASKS']
Landroid/accounts/AccountManager;->invalidateAuthToken(Ljava/lang/String; Ljava/lang/String;)V : ['android.permission.MANAGE_ACCOUNTS', 'android.permission.USE_CREDENTIALS']
Landroid/net/ConnectivityManager;->getNetworkInfo(I)Landroid/net/NetworkInfo; : ['android.permission.ACCESS_NETWORK_STATE']
Landroid/net/ConnectivityManager;->isActiveNetworkMetered()Z : ['android.permission.ACCESS_NETWORK_STATE']
Landroid/net/ConnectivityManager;->getActiveNetworkInfo()Landroid/net/NetworkInfo; : ['android.permission.ACCESS_NETWORK_STATE']
Landroid/telephony/TelephonyManager;->getDeviceId()Ljava/lang/String; : ['android.permission.READ_PHONE_STATE']
Landroid/telephony/TelephonyManager;->getSubscriberId()Ljava/lang/String; : ['android.permission.READ_PHONE_STATE']
Landroid/telephony/TelephonyManager;->getSimSerialNumber()Ljava/lang/String; : ['android.permission.READ_PHONE_STATE']

输出的系统类、调用方法、需要的权限。

检索某系统方法被调用的地方并打印

import os
import sys

# 引入androguard的路径,根据个人存放的位置而定
androguard_module_path = os.path.join(os.path.dirname(os.path.abspath(__file__)), 'androguard')
if not androguard_module_path in sys.path:
    sys.path.append(androguard_module_path)

from androguard.misc import AnalyzeAPK
from androguard.core.androconf import load_api_specific_resource_module

path = r"/apk"
out_path = r"/out"
files = []
path_list = os.listdir(path)
path_list.sort()
for name in path_list:
    if os.path.isfile(os.path.join(path, name)):
        files.append(name)


def main():
    for apkFile in files:
        file_name = os.path.splitext(apkFile)[0]
        print(apkFile)
        out = AnalyzeAPK(path + '/' + apkFile)
        a = out[0]
        d = out[1]
        dx = out[2]

        for meth in dx.classes['Ljava/io/File;'].get_methods():
            print("usage of method {}".format(meth.name))
            # 拿到改函数的引用函数
            for _, call, _ in meth.get_xref_from():
            print("  called by -> {} -- {}".format(call.class_name, call.name))

if __name__ == '__main__':
    main()

输出结果

usage of method getPath
  called by -> Landroid/support/v4/util/AtomicFile; -- <init>
usage of method <init>
  called by -> Landroid/support/v4/util/AtomicFile; -- <init>
usage of method delete
  called by -> Landroid/support/v4/util/AtomicFile; -- failWrite
  called by -> Landroid/support/v4/util/AtomicFile; -- delete
  called by -> Landroid/support/v4/util/AtomicFile; -- delete
  called by -> Landroid/support/v4/util/AtomicFile; -- startWrite
  called by -> Landroid/support/v4/util/AtomicFile; -- openRead
  called by -> Landroid/support/v4/util/AtomicFile; -- finishWrite
usage of method renameTo
  called by -> Landroid/support/v4/util/AtomicFile; -- openRead
  called by -> Landroid/support/v4/util/AtomicFile; -- failWrite
  called by -> Landroid/support/v4/util/AtomicFile; -- startWrite
usage of method exists
  called by -> Landroid/support/v4/util/AtomicFile; -- startWrite
  called by -> Landroid/support/v4/util/AtomicFile; -- openRead
  called by -> Landroid/support/v4/util/AtomicFile; -- startWrite
usage of method getParentFile
  called by -> Landroid/support/v4/util/AtomicFile; -- startWrite
usage of method mkdir
  called by -> Landroid/support/v4/util/AtomicFile; -- startWrite
  • ‘Ljava/io/File;’ 需要检测的类
  • meth.get_xref_from() 那该类中函数被引用的地方
  • 你也可以自己搞个数组,配置好要检查的相关函数,然后在上面代码中加入if过滤即可
    如果你想找Android系统定位,被应用哪些方法调用,你就可以这样做:

    dx.classes['Landroid/location/LocationManager;']

    再运行一遍脚本就可以看到结果了。

    结束

    写这篇博客,主要目的是为了让更多人知道这个东西吧,我自己去搜索文章的时候发现并没有多少可以参考的,导致很多人无从下手,但其实官方文档也很详细,但是英文的,看起来也不方便,也希望这篇简短的文章给你提供帮助,如果有问题请再联系我或留言评论

    欢迎关注新网站

  • http://jetpack.net.cn
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