2、hook绕过

启用frida并更改端口没有发现检测行为但是直接hook会闪退

自动草稿

打印so 调用堆栈

function hook_pthread(){ var pthread_create_addr = Module.findExportByName(null, 'pthread_create var pthread_create = new NativeFunction(pthread_create_addr, "int", ["pointer", "pointer", "pointer", "pointer"]);  Interceptor.replace(pthread_create_addr, new NativeCallback(function (parg0, parg1, parg2, parg3) { var so_name = Process.findModuleByAddress(parg2).name; var so_path = Process.findModuleByAddress(parg2).path; var so_base = Module.getBaseAddress(so_name); var offset = parg2 - so_base; var PC = 0; if ((so_name.indexOf("libexec.so") > -1)) { console.log("find thread func offset", so_name, offset); } else { PC = pthread_create(parg0, parg1, parg2, parg3); } return PC; }, "int", ["pointer", "pointer", "pointer", "pointer"]))}hook_pthread();

自动草稿

找到了libexec.so开启pthread_create的偏移量，对其进行bypass，即

function hook_pthread() {  var pthread_create_addr = Module.findExportByName(null, 'pthread_create');  var pthread_create = new NativeFunction(pthread_create_addr, "int", ["pointer", "pointer", "pointer", "pointer"]); Interceptor.replace(pthread_create_addr, new NativeCallback(function (parg0, parg1, parg2, parg3) { var so_name = Process.findModuleByAddress(parg2).name; var so_path = Process.findModuleByAddress(parg2).path; var so_base = Module.getBaseAddress(so_name); var offset = parg2 - so_base; var PC = 0; if ((so_name.indexOf("libexec.so") > -1)) { console.log("find thread func offset", so_name, offset); if ((207076 === offset)) { console.log("anti bypass"); } else if (207308 === offset) { console.log("anti bypass"); } else if (283820 === offset) { console.log("anti bypass"); } else if (286488 === offset) { console.log("anti bypass"); } else if (292416 === offset) { console.log("anti bypass"); } else if (78136 === offset) { console.log("anti bypass"); } else if (293768 === offset) { console.log("anti bypass"); } else { PC = pthread_create(parg0, parg1, parg2, parg3); } } else { PC = pthread_create(parg0, parg1, parg2, parg3); } return PC; }, "int", ["pointer", "pointer", "pointer", "pointer"]))}hook_pthread();

自动草稿

已经对其进行绕过frida的检测。

3、class的遍历和hook

绕过frida的检测之后，开始对其加载的class以及class中的函数进行遍历

Java.enumerateLoadedClasses({ onMatch: function(className) { console.log("found class >> " + className); //遍历类中所有的方法和属性 var jClass = Java.use(className); console.log(JSON.stringify({ _name: className, _methods: Object.getOwnPropertyNames(jClass.__proto__).filter(function(m) { return !m.startsWith('$') // filter out Frida related special properties || m == 'class' || m == 'constructor' // optional }),  _fields: jClass.class.getFields().map(function(f) { return f.toString() }) }, null, 2)); //遍历类中所有的方法和属性 }, onComplete: function() { console.log("[*] class enuemration complete"); } });

自动草稿

class和函数大部分已经被遍历出来了，但是由于是加固的，部分函数并没有被加载出来(意料之中)，利用常规的框架尝试去执行

//框架为if(Java.available) { Java.perform(function(){ var application = Java.use("android.app.Application");  application.attach.overload('android.content.Context').implementation = function(context) { var result = this.attach(context); // 先执行原来的attach方法 var classloader = context.getClassLoader(); // 获取classloader Java.classFactory.loader = classloader; var Hook_class = Java.classFactory.use("com.xxx.xxx");  // app的类 console.log("Hook_class: " + Hook_class); // 下面代码和写正常的hook一样 Hook_class.函数.implementation = function()  // 有参数填参数{ }  return result; } });}

发现会执行不成功，说明加固后的app没有用常规的classloader去加载函数。因此需要去遍历在加载app的时候，是哪些classloader被加载
1、可以通过重加载指定classloader去使得脱壳后的源码能在内存中被找到
2、可以一次性重加载所有调用的classloader去执行

//获取加固的classloader并hook函数Java.enumerateClassLoaders({ onMatch: function(loader){ // 每次匹配到，都要把匹配到的赋值给java默认的loader Java.classFactory.loader = loader; var TryClass; // console.log(loader); // 输出被加载的classloader // 没报错就hook到了，报错了就hook下一个，如果全都报错了，没打印东西，那可能就是hook错了。 try{ // 每一次加载尝试是否可以找到想要的class TryClass = Java.use("cn.xxx"); // 需要被加载之后查询的类 TryClass.xx.implementation = function(p1,p2){ // 类的函数 console.log('p1:'+p1) console.log('p2:'+p2) return this.xx(p1,p2) } }catch(error){ if(error.message.includes("ClassNotFoundException")){ console.log(" You are trying to load encrypted class, trying next loader"); } else{ console.log(error.message); } } }, onComplete: function(){ }})