Android逆向之hook框架frida篇

转载自 [原文](https://www.jianshu.com/p/ca8381d3e094)

前言

Frida是一款基于python + javascript 的hook框架，通杀android\ios\linux\win\osx等各平台，由于是基于脚本的交互，因此相比xposed和substrace cydia更加便捷，本文重点介绍Frida在android下面的使用。Frida的官网为：http://www.frida.re/

安装和搭建Frida环境

首先要保证你的android手机已经root。通过pip安装frida:

pip install frida

下载frida-server：

frida_server的下载地址：https://github.com/frida/frida/releases

到android手机上并且运行

adb push frida-server /data/local/tmp/
adb shell
su
cd /data/local/tmp/
chmod 777 frida-server
./frida-server

转发android TCP端口到本地：

adb forward tcp:27042 tcp:27042
adb forward tcp:27043 tcp:27043

测试frida环境，如果出现android手机的进程列表说明搭建成功：

frida-ps -R
PID Name

---

2700 acceleratord
2713 adbd
2798 agnsscontrol
2799 agnsslog
2195 akmd09911
8078 android.process.acore
31283 android.process.media
2185 atcmdserver
4939 chargelogcat
2796 chr_logd
22856 com.android.browser
7912 com.android.contacts
22417 com.android.gallery3d
….

得到android手机当前最前端Activity所在的进程

get_front_app.py

其中get_front_app.py的内容如下：

import frida
rdev = frida.get_remote_device()
front_app = rdev.get_frontmost_application()
print front_app

枚举android手机所有的进程

enum_process.py

enum_process.py内容如下：

import frida
rdev = frida.get_remote_device()
processes = rdev.enumerate_processes()
for process in processes:
    print process

枚举某个进程加载的所有模块以及模块中的导出函数

import frida
rdev = frida.get_remote_device()
session = rdev.attach("com.tencent.mm")  #如果存在两个一样的进程名可以采用rdev.attach(pid)的方式
modules = session.enumerate_modules()
for module in modules:
    print module
    export_funcs = module.enumerate_exports()
    print "\tfunc_name\tRVA"
    for export_func in export_funcs:
        print "\t%s\t%s"%(export_func.name,hex(export_func.relative_address))

hook android的native函数

import frida
import sys
rdev = frida.get_remote_device()
session = rdev.attach("com.tencent.mm")
scr = """
Interceptor.attach(Module.findExportByName("libc.so" , "open"), {
    onEnter: function(args) {
        send("open("+Memory.readCString(args[0])+","+args[1]+")");
    },
    onLeave:function(retval){

    }
});
"""
script = session.create_script(scr)
def on_message(message ,data):
    print message
script.on("message" , on_message)
script.load()
sys.stdin.read()

hook android的java层函数

如下代码为hook微信（测试版本为6.3.13，不同版本由于混淆名字的随机生成的原因或者代码改动导致类名不一样）
com.tencent.mm.sdk.platformtools.ay类的随机数生成函数，让微信猜拳随机（type=2），而摇色子总是为6点（type=5）

import frida
import sys
rdev = frida.get_remote_device()
session = rdev.attach("com.tencent.mm")

scr = """
Java.perform(function () {
var ay = Java.use("com.tencent.mm.sdk.platformtools.ay");
ay.pu.implementation = function(){
    var type = arguments[0];
    send("type="+type);
    if (type == 2)
    {
    return this.pu(type);
    }
    else
    {
    return 5;
    }
};

});
"""

script = session.create_script(scr)
def on_message(message ,data):
    print message
script.on("message" , on_message)
script.load()
sys.stdin.read()

通过frida向android进程注入dex

import frida, sys, optparse, re
def on_message(message, data):
    if message['type'] == 'send':
        print("[*] {0}".format(message['payload']))
    else:
        print(message)

jscode = """
Java.perform(function () {
    var currentApplication = Java.use("android.app.ActivityThread").currentApplication();
    var context = currentApplication.getApplicationContext();
    var pkgName = context.getPackageName();
    var dexPath = "%s";
    var entryClass = "%s";
    Java.openClassFile(dexPath).load();
    console.log("inject " + dexPath +" to " + pkgName + " successfully!")
    Java.use(entryClass).%s("%s");
    console.log("call entry successfully!")
});
"""

def checkRequiredArguments(opts, parser):
    missing_options = []
    for option in parser.option_list:
        if re.match(r'^\[REQUIRED\]', option.help) and eval('opts.' + option.dest) == None:
            missing_options.extend(option._long_opts)
    if len(missing_options) > 0:
        parser.error('Missing REQUIRED parameters: ' + str(missing_options))

if __name__ == "__main__":
    usage = "usage: python %prog [options] arg\n\n" \
            "example: python %prog -p com.android.launcher " \
            "-f /data/local/tmp/test.apk " \
            "-e com.parker.test.DexMain/main " \
            "\"hello fridex!\""
    parser = optparse.OptionParser(usage)
    parser.add_option("-p", "--package", dest="pkg", type="string",
                      help="[REQUIRED]package name of the app to be injected.")
    parser.add_option("-f", "--file", dest="dexPath", type="string",
                      help="[REQUIRED]path of the dex")
    parser.add_option("-e", "--entry", dest="entry", type="string",
                      help="[REQUIRED]the entry function Name.")

    (options, args) = parser.parse_args()
    checkRequiredArguments(options, parser)
    if len(args) == 0:
        arg = ""
    else:
        arg = args[0]

    pkgName = options.pkg
    dexPath = options.dexPath
    entry = options.entry.split("/")
    if len(entry) > 1:
        entryClass = entry[0]
        entryFunction = entry[1]
    else:
        entryClass = entry[0]
        entryFunction = "main"

    process = frida.get_usb_device(1).attach(pkgName)
    jscode = jscode%(dexPath, entryClass, entryFunction, arg)
    script = process.create_script(jscode)
    script.on('message', on_message)
    print('[*] Running fridex')
    script.load()
    sys.stdin.read()

通过注入抛出异常代码实现跟踪程序调用栈

在<>这本书中第八章有介绍通过重打包写入异常代码进行栈跟踪，但是这样比较麻烦，使用frida注入更方便。

frida的相关资源

https://github.com/dweinstein/awesome-frida
http://jaq.alibaba.com/community/art/show?articleid=816
https://koz.io/using-frida-on-android-without-root/
http://www.ninoishere.com/frida-learn-by-example/
https://github.com/TheCjw/Frida-Android-Scripts