App逆向案例 X嘟牛 - Frida监听 & WT-JS工具还原（一）

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前言

该文章使用了Frida、JDAX-GUI、Charles、夜神模拟器、WT-JS等工具
主要编程语言Python部分涉及到JavaScript、Java

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提示以下是本篇文章正文内容下面案例可供参考

一、资源推荐

Frida - App逆向 概念介绍https://blog.csdn.net/EXIxiaozhou/article/details/128112421
安装抓包工具以及模拟器 App抓包https://blog.csdn.net/EXIxiaozhou/article/details/127767808
JS逆向 Frida - 夜神模拟器安装配置 基本使用https://blog.csdn.net/EXIxiaozhou/article/details/128035059
ApkScan-PKID 查壳工具下载https://blog.csdn.net/EXIxiaozhou/article/details/127196615
Frida-Dexdump 脱壳工具下载使用https://blog.csdn.net/EXIxiaozhou/article/details/128208068
JDAX-GUI 反编译工具下载https://blog.csdn.net/EXIxiaozhou/article/details/127207762
JS逆向加密解密工具 下载使用https://blog.csdn.net/EXIxiaozhou/article/details/128034062
X嘟牛Apk下载https://pan.baidu.com/s/1HMxGZx9m8QZwAZSZPBiHwQ?pwd=m1qk
示例代码下载https://pan.baidu.com/s/1rfFBzLeMQgKaajyUIhCb9Q?pwd=ad7i#list/path=%2F

二、App抓包分析

1、打开Charles、夜神模拟器开始App抓包
2、登录接口的urlhttp://api.dodovip.com/api/user/login

三、反编译逆向分析

提示可以把反编译的Java代码复制到IDEA分析运行这样会提高逆向的效率
加密参数的关键词“Encrypt”点击"转到"来到加密代码处


MD5加密生成sign参数public static String paraMap(Map<String, String> addMap, String append, String sign)

DES加密生成encryptpublic static String encodeDesMap(String data, String desKey, String desIV)

四、还原JS加密

1.Hook示例代码

import frida
import sys

def on_message(message, data):
    if message['type'] == 'send':
        print("[*] {0}".format(message['payload']))
    else:
        print(message)       
        
java_code = """
    Java.perform(function(){
        var hooksClass = Java.use("com.dodonew.online.http.RequestUtil");
        hooksClass.paraMap.overload('java.util.Map', 'java.lang.String', 'java.lang.String').implementation = function (addMap, append, sign) {
            console.log("MD5加密参数1为"+addMap);
            console.log("MD5加密参数2为"+append);
            console.log("MD5加密参数3为"+sign);
            var result = this.paraMap(addMap, append, sign);
            console.log("sign加密结果"+result);
            console.log("sign加密结果"+result['equtype']);
            return result;
        }
    })
    Java.perform(function(){
        var hooksClass = Java.use("com.dodonew.online.http.RequestUtil");
        hooksClass.encodeDesMap.overload('java.lang.String', 'java.lang.String', 'java.lang.String').implementation = function (data, desKey, desIV) {
            console.log("DES加密参数1为"+data);
            console.log("DES加密参数2为"+desKey);
            console.log("DES加密参数3为"+desIV);
            var result = this.encodeDesMap(data, desKey, desIV);
            console.log("encrypt加密结果"+result);
            return result;
        }
    })
"""       

# get_usb_device改成get_remote_device方法get_usb_device有的电脑会报错
process = frida.get_remote_device().attach(3179)  # 'App名称', 或 App应用的 Process Pid
script = process.create_script(java_code)  # 把js的hook脚本注入到进程里面
script.on('message', on_message)
print('[*] Running CTF')
script.load()
sys.stdin.read()

2.JS还原

1、运行Hook代码

2、分析加密参数
sign的加密参数equtype=ANDROID&loginImei=Android354730613429558&timeStamp=1670240167016&userPwd=123456&username=15888888888&key=sdlkjsdljf0j2fsjk
sign的MD5加密结果B5BC60EB36B54B683656B56B88714E00
3、WT-JS还原MD5

4、使用WT-JS生成MD5的加密代码

5、查看生成的代码

6、WT-JS还原DES
public static final String BASE_DES_IV = “32028092”;
public static final String BASE_DES_KEY = “65102933”;
这里有个小坑分析apk源码可以发现key先进行了MD5加密后才作为参数传入创建DES加密对象

这里先用WT-JS生成DES加密代码

7、查看WT-JS生成的DES加密代码

五、python登录实现代码

1.python示例代码

import time
import execjs
import urllib
import requests


class DuDuNiu(object):
    def __init__(self):
        with open(file="js_code.js", mode='r', encoding='utf-8') as fis:
            self.js_code = fis.read()
        self.js_obj = execjs.compile(source=self.js_code, cwd=r'D:\software_install\nodejs\node_modules')
        self.username = "15888888888"
        self.password = "123456"
        self.time_string = str(int(time.time() * 1000))
        self.headers = {
            'User-Agent': 'Dalvik/2.1.0 (Linux; U; Android 7.1.2; SM-G9810 Build/QP1A.190711.020)'
        }

    def get_login_params(self):
        items = {
            'equtype': 'ANDROID', 'loginImei': 'Android354730613429558', 'timeStamp': self.time_string,
            "userPwd": self.password, "username": self.username
        }
        content = ''
        for keys in items:
            content += f"{keys}={items[keys]}&"
        append = "sdlkjsdljf0j2fsjk"
        content += f"key={append}"
        print(content)
        sign = str(self.js_obj.call('MD5_Encrypt', content)).upper()
        print("sign参数:", sign)
        items['sign'] = sign
        content = str(items).replace(' ', '')
        print(content)
        encrypt_string = self.js_obj.call('DES_Encrypt', content)
        print("login参数:", encrypt_string)
        return encrypt_string

    def des_decrypt(self, content):
        result = self.js_obj.call('DES_Decrypt', content)
        return result

    def register(self):
        pass

    def login(self):
        login_url = 'http://api.dodovip.com/api/user/login'
        params = {"Encrypt": self.get_login_params()}
        login_response = requests.post(url=login_url, headers=self.headers, json=params)
        login_result = str(login_response.text)
        print("login响应:", login_result)
        login_result = self.des_decrypt(content=login_result)
        print(urllib.parse.unquote(login_result))

    def runs(self):
        self.login()


obj = DuDuNiu()
obj.runs()

2.python运行结果

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总结

以上就是今天要讲的内容本文仅仅简单介绍了一个app的逆向案例需要仔细观察一下加密的参数以及加密结果的变化该示例用的加密参数都是同一种希望对大家有所帮助