Frida Android hook _ Sakura の blog
本文由 简悦 SimpRead 转码， 原文地址 eternalsakura13.com
建了一个知识星球：天问之路如果想学习二进制安全，或者和我交流，欢迎来这里找我 w Frida 环境 https://github.com/frida/frida pyenvpython 全版本随机切换，这里提供……
建了一个知识星球：天问之路
如果想学习二进制安全，或者和我交流，欢迎来这里找我 w
Frida 环境
https://github.com/frida/frida
pyenv
python 全版本随机切换，这里提供 macOS 上的配置方法
brew update
brew install pyenv
echo -e 'if command -v pyenv 1>/dev/null 2>&1; then\n eval "$(pyenv init -)"\nfi' >> ~/.bash_profile
下载一个3.8.2，下载真的很慢，要慢慢等
pyenv install 3.8.2
pyenv versions
sakura@sakuradeMacBook-Pro:~$ pyenv versions
system
* 3.8.2 (set by /Users/sakura/.python-version)
切换到我们装的
pyenv local 3.8.2
python -V
pip -V
原本系统自带的
python local system
python -V
另外当你需要临时禁用 pyenv 的时候
把这个注释了然后另开终端就好了。
关于卸载某个 python 版本
Uninstalling Python Versions
As time goes on, you will accumulate Python versions in your $(pyenv root)/versions directory.
To remove old Python versions, pyenv uninstall command to automate the removal process.
Alternatively, simply rm -rf the directory of the version you want to remove. You can find the directory of a particular Python version with the pyenv prefix command, e.g. pyenv prefix 2.6.8.
frida 安装
如果直接按下述安装则会直接安装 frida 和 frida-tools 的最新版本。
pip install frida-tools
frida --version
frida-ps --version
我们也可以自由安装旧版本的 frida，例如 12.8.0
pyenv install 3.7.7
pyenv local 3.7.7
pip install frida==12.8.0
pip install frida-tools==5.3.0
老版本 frida 和对应关系
对应关系很好找
安装 objection
pyenv local 3.8.2
pip install objection
objection -h
pyenv local 3.7.7
pip install objection==1.8.4
objection -h
frida 使用
下载 frida-server 并解压，在这里下载 frida-server-12.8.0
先 adb shell，然后切换到 root 权限, 把之前 push 进来的 frida server 改个名字叫 fs
然后运行 frida
adb push /Users/sakura/Desktop/lab/alpha/tools/android/frida-server-12.8.0-android-arm64 /data/local/tmp
chmod +x fs
./fs
如果要监听端口，就
./fs -l 0.0.0.0:8888
frida 开发环境搭建
-
安装
git clone https://github.com/oleavr/frida-agent-example.git cd frida-agent-example/ npm install -
使用 vscode 打开此工程，在 agent 文件夹下编写 js，会有智能提示。
-
npm run watch会监控代码修改自动编译生成 js 文件 -
python 脚本或者 cli 加载_agent.js
frida -U -f com.example.android --no-pause -l _agent.js
下面是测试脚本
s1.js
function main() {
Java.perform(function x() {
console.log("sakura")
})
}
setImmediate(main)
loader.py
import time
import frida
device8 = frida.get_device_manager().add_remote_device("192.168.0.9:8888")
pid = device8.spawn("com.android.settings")
device8.resume(pid)
time.sleep(1)
session = device8.attach(pid)
with open("si.js") as f:
script = session.create_script(f.read())
script.load()
input() #等待输入
解释一下，这个脚本就是先通过frida.get_device_manager().add_remote_device来找到 device, 然后 spawn 方式启动 settings，然后 attach 到上面，并执行 frida 脚本。
FRIDA 基础
frida 查看当前存在的进程
frida-ps -U查看通过 usb 连接的 android 手机上的进程。
sakura@sakuradeMacBook-Pro:~$ frida-ps --help
Usage: frida-ps [options]
Options:
--version show program's version number and exit
-h, --help show this help message and exit
-D ID, --device=ID connect to device with the given ID
-U, --usb connect to USB device
-R, --remote connect to remote frida-server
-H HOST, --host=HOST connect to remote frida-server on HOST
-a, --applications list only applications
-i, --installed include all installed applications
sakura@sakuradeMacBook-Pro:~$ frida-ps -U
PID Name
----- ---------------------------------------------------
3640 ATFWD-daemon
707 adbd
728 adsprpcd
26041 android.hardware.audio@2.0-service
741 android.hardware.biometrics.fingerprint@
通过 grep 过滤就可以找到我们想要的包名。
frida 打印参数和修改返回值
package myapplication.example.com.frida_demo;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
public class MainActivity extends AppCompatActivity {
private String total = "@@@###@@@";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
while (true){
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
fun(50,30);
Log.d("sakura.string" , fun("LoWeRcAsE Me!!!!!!!!!"));
}
}
void fun(int x , int y ){
Log.d("sakura.Sum" , String.valueOf(x+y));
}
String fun(String x){
total +=x;
return x.toLowerCase();
}
String secret(){
return total;
}
}
function main() {
console.log("Enter the Script!");
Java.perform(function x() {
console.log("Inside Java perform");
var MainActivity = Java.use("myapplication.example.com.frida_demo.MainActivity");
// 重载找到指定的函数
MainActivity.fun.overload('java.lang.String').implementation = function (str) {
//打印参数
console.log("original call : str:" + str);
//修改结果
var ret_value = "sakura";
return ret_value;
};
})
}
setImmediate(main);
sakura@sakuradeMacBook-Pro:~$ frida-ps -U | grep frida
8738 frida-helper-32
8897 myapplication.example.com.frida_demo
// -f是通过spawn，也就是重启apk注入js
sakura@sakuradeMacBook-Pro:~$ frida -U -f myapplication.example.com.frida_demo -l frida_demo.js
...
original call : str:LoWeRcAsE Me!!!!!!!!!
12-21 04:46:49.875 9594-9594/myapplication.example.com.frida_demo D/sakura.string: sakura
frida 寻找 instance，主动调用。
function main() {
console.log("Enter the Script!");
Java.perform(function x() {
console.log("Inside Java perform");
var MainActivity = Java.use("myapplication.example.com.frida_demo.MainActivity");
//overload 选择被重载的对象
MainActivity.fun.overload('java.lang.String').implementation = function (str) {
//打印参数
console.log("original call : str:" + str);
//修改结果
var ret_value = "sakura";
return ret_value;
};
// 寻找类型为classname的实例
Java.choose("myapplication.example.com.frida_demo.MainActivity", {
onMatch: function (x) {
console.log("find instance :" + x);
console.log("result of secret func:" + x.secret());
},
onComplete: function () {
console.log("end");
}
});
});
}
setImmediate(main);
frida rpc
function callFun() {
Java.perform(function fn() {
console.log("begin");
Java.choose("myapplication.example.com.frida_demo.MainActivity", {
onMatch: function (x) {
console.log("find instance :" + x);
console.log("result of fun(string) func:" + x.fun(Java.use("java.lang.String").$new("sakura")));
},
onComplete: function () {
console.log("end");
}
})
})
}
rpc.exports = {
callfun: callFun
};
import time
import frida
device = frida.get_usb_device()
pid = device.spawn(["myapplication.example.com.frida_demo"])
device.resume(pid)
time.sleep(1)
session = device.attach(pid)
with open("frida_demo_rpc_call.js") as f:
script = session.create_script(f.read())
def my_message_handler(message, payload):
print(message)
print(payload)
script.on("message", my_message_handler)
script.load()
script.exports.callfun()
sakura@sakuradeMacBook-Pro:~/gitsource/frida-agent-example/agent$ python frida_demo_rpc_loader.py
begin
find instance :myapplication.example.com.frida_demo.MainActivity@1d4b09d
result of fun(string):sakura
end
frida 动态修改
即将手机上的 app 的内容发送到 PC 上的 frida python 程序，然后处理后返回给 app，然后 app 再做后续的流程，核心是理解send/recv函数
<TextView
android:id="@+id/textView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="please input username and password"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<EditText
android:id="@+id/editText"
android:layout_width="fill_parent"
android:layout_height="40dp"
android:hint="username"
android:maxLength="20"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="1.0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.095" />
<EditText
android:id="@+id/editText2"
android:layout_width="fill_parent"
android:layout_height="40dp"
android:hint="password"
android:maxLength="20"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.239" />
<Button
android:id="@+id/button"
android:layout_width="100dp"
android:layout_height="35dp"
android:layout_gravity="right|center_horizontal"
android:text="提交"
android:visibility="visible"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.745" />
public class MainActivity extends AppCompatActivity {
EditText username_et;
EditText password_et;
TextView message_tv;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
password_et = (EditText) this.findViewById(R.id.editText2);
username_et = (EditText) this.findViewById(R.id.editText);
message_tv = ((TextView) findViewById(R.id.textView));
this.findViewById(R.id.button).setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (username_et.getText().toString().compareTo("admin") == 0) {
message_tv.setText("You cannot login as admin");
return;
}
//hook target
message_tv.setText("Sending to the server :" + Base64.encodeToString((username_et.getText().toString() + ":" + password_et.getText().toString()).getBytes(), Base64.DEFAULT));
}
});
}
}
先分析问题，我的最终目标是让 message_tv.setText 可以” 发送”username 为 admin 的 base64 字符串。 那肯定是 hook TextView.setText 这个函数。
console.log("Script loaded successfully ");
Java.perform(function () {
var tv_class = Java.use("android.widget.TextView");
tv_class.setText.overload("java.lang.CharSequence").implementation = function (x) {
var string_to_send = x.toString();
var string_to_recv;
send(string_to_send); // send data to python code
recv(function (received_json_object) {
string_to_recv = received_json_object.my_data
console.log("string_to_recv: " + string_to_recv);
}).wait(); //block execution till the message is received
var my_string = Java.use("java.lang.String").$new(string_to_recv);
this.setText(my_string);
}
});
import time
import frida
import base64
def my_message_handler(message, payload):
print(message)
print(payload)
if message["type"] == "send":
print(message["payload"])
data = message["payload"].split(":")[1].strip()
print( 'message:', message)
#data = data.decode("base64")
#data = data
data = str(base64.b64decode(data))
print( 'data:',data)
user, pw = data.split(":")
print( 'pw:',pw)
#data = ("admin" + ":" + pw).encode("base64")
data = str(base64.b64encode(("admin" + ":" + pw).encode()))
print( "encoded data:", data)
script.post({"my_data": data}) # send JSON object
print( "Modified data sent")
device = frida.get_usb_device()
pid = device.spawn(["myapplication.example.com.frida_demo"])
device.resume(pid)
time.sleep(1)
session = device.attach(pid)
with open("frida_demo2.js") as f:
script = session.create_script(f.read())
script.on("message", my_message_handler)
script.load()
input()
sakura@sakuradeMacBook-Pro:~/gitsource/frida-agent-example/agent$ python frida_demo_rpc_loader2.py
Script loaded successfully
{'type': 'send', 'payload': 'Sending to the server :c2FrdXJhOjEyMzQ1Ng==\n'}
None
Sending to the server :c2FrdXJhOjEyMzQ1Ng==
message: {'type': 'send', 'payload': 'Sending to the server :c2FrdXJhOjEyMzQ1Ng==\n'}
data: b'sakura:123456'
pw: 123456'
encoded data: b'YWRtaW46MTIzNDU2Jw=='
Modified data sent
string_to_recv: b'YWRtaW46MTIzNDU2Jw=='
参考链接：https://github.com/Mind0xP/Frida-Python-Binding
API List
Java.choose(className: string, callbacks: Java.ChooseCallbacks): void
通过扫描 Java VM 的堆来枚举 className 类的 live instance。Java.use(className: string): Java.Wrapper<{}>
动态为 className 生成 JavaScript Wrapper，可以通过调用$new()来调用构造函数来实例化对象。 在实例上调用$dispose()以对其进行显式清理，或者等待 JavaScript 对象被 gc。Java.perform(fn: () => void): void
Function to run while attached to the VM.
Ensures that the current thread is attached to the VM and calls fn. (This isn’t necessary in callbacks from Java.)
Will defer calling fn if the app’s class loader is not available yet. Use Java.performNow() if access to the app’s classes is not needed.send(message: any, data?: ArrayBuffer | number[]): void
任何 JSON 可序列化的值。 将 JSON 序列化后的 message 发送到您的基于 Frida 的应用程序，并包含 (可选) 一些原始二进制数据。 The latter is useful if you e.g. dumped some memory using NativePointer#readByteArray().recv(callback: MessageCallback): MessageRecvOperation
Requests callback to be called on the next message received from your Frida-based application.
This will only give you one message, so you need to call recv() again to receive the next one.wait(): void
堵塞，直到 message 已经 receive 并且 callback 已经执行完毕并返回
Frida 动静态结合分析
Objection
- 参考这篇文章
实用 FRIDA 进阶：内存漫游、hook anywhere、抓包 - objection
https://pypi.org/project/objection/
objection 启动并注入内存
objection -d -g package_name explore
sakura@sakuradeMacBook-Pro:~$ objection -d -g com.android.settings explore
[debug] Agent path is: /Users/sakura/.pyenv/versions/3.7.7/lib/python3.7/site-packages/objection/agent.js
[debug] Injecting agent...
Using USB device `Google Pixel`
[debug] Attempting to attach to process: `com.android.settings`
[debug] Process attached!
Agent injected and responds ok!
_ _ _ _
___| |_|_|___ ___| |_|_|___ ___
| . | . | | -_| _| _| | . | |
|___|___| |___|___|_| |_|___|_|_|
|___|(object)inject(ion) v1.8.4
Runtime Mobile Exploration
by: @leonjza from @sensepost
[tab] for command suggestions
com.android.settings on (google: 8.1.0) [usb] #
objection memory
查看内存中加载的 module memory list modules
com.android.settings on (google: 8.1.0) [usb] # memory list modules
Save the output by adding `--json modules.json` to this command
Name Base Size Path
----------------------------------------------- ------------ -------------------- ---------------------------------------------------------------
app_process64 0x64ce143000 32768 (32.0 KiB) /system/bin/app_process64
libandroid_runtime.so 0x7a90bc3000 1990656 (1.9 MiB) /system/lib64/libandroid_runtime.so
libbinder.so 0x7a9379f000 557056 (544.0 KiB) /system/lib64/libbinder.so
查看库的导出函数 memory list exports libssl.so
com.android.settings on (google: 8.1.0) [usb] # memory list exports libssl.so
Save the output by adding `--json exports.json` to this command
Type Name Address
-------- ----------------------------------------------------- ------------
function SSL_use_certificate_ASN1 0x7c8ff006f8
function SSL_CTX_set_dos_protection_cb 0x7c8ff077b8
function SSL_SESSION_set_ex_data 0x7c8ff098f4
function SSL_CTX_set_session_psk_dhe_timeout 0x7c8ff0a754
function SSL_CTX_sess_accept 0x7c8ff063b8
function SSL_select_next_proto 0x7c8ff06a74
dump 内存空间
-
memory dump all 文件名 -
memory dump from_base 起始地址 字节数 文件名搜索内存空间
Usage: memory search "<pattern eg: 41 41 41 ?? 41>" (--string) (--offsets-only)
objection android
内存堆搜索实例 android heap search instances 类名
在堆上搜索类的实例
sakura@sakuradeMacBook-Pro:~$ objection -g myapplication.example.com.frida_demo explore
Using USB device `Google Pixel`
Agent injected and responds ok!
[usb] # android heap search instances myapplication.example.com.frida_demo
.MainActivity
Class instance enumeration complete for myapplication.example.com.frida_demo.MainActivity
Handle Class toString()
-------- ------------------------------------------------- ---------------------------------------------------------
0x2102 myapplication.example.com.frida_demo.MainActivity myapplication.example.com.frida_demo.MainActivity@5b1b0af
调用实例的方法 android heap execute 实例ID 实例方法
查看当前可用的 activity 或者 service android hooking list activities/services
直接启动 activity 或者服务 android intent launch_activity/launch_service activity/服务
android intent launch_activity com.android.settings.DisplaySettings
这个命令比较有趣的是用在如果有些设计的不好，可能就直接绕过了密码锁屏等直接进去。
com.android.settings on (google: 8.1.0) [usb] # android hooking list services
com.android.settings.SettingsDumpService
com.android.settings.TetherService
com.android.settings.bluetooth.BluetoothPairingService
列出内存中所有的类 android hooking list classes
在内存中所有已加载的类中搜索包含特定关键词的类。android hooking search classes display
com.android.settings on (google: 8.1.0) [usb] # android hooking search classes display
[Landroid.icu.text.DisplayContext$Type;
[Landroid.icu.text.DisplayContext;
[Landroid.view.Display$Mode;
android.hardware.display.DisplayManager
android.hardware.display.DisplayManager$DisplayListener
android.hardware.display.DisplayManagerGlobal
内存中搜索指定类的所有方法 android hooking list class_methods 类名
com.android.settings on (google: 8.1.0) [usb] # android hooking list class_methods java.nio.charset.Charset
private static java.nio.charset.Charset java.nio.charset.Charset.lookup(java.lang.String)
private static java.nio.charset.Charset java.nio.charset.Charset.lookup2(java.lang.String)
private static java.nio.charset.Charset java.nio.charset.Charset.lookupViaProviders(java.lang.String)
在内存中所有已加载的类的方法中搜索包含特定关键词的方法 android hooking search methods display
知道名字开始在内存里搜就很有用
com.android.settings on (google: 8.1.0) [usb] # android hooking search methods display
Warning, searching all classes may take some time and in some cases, crash the target application.
Continue? [y/N]: y
Found 5529 classes, searching methods (this may take some time)...
android.app.ActionBar.getDisplayOptions
android.app.ActionBar.setDefaultDisplayHomeAsUpEnabled
android.app.ActionBar.setDisplayHomeAsUpEnabled
hook 类的方法（hook 类里的所有方法 / 具体某个方法）
-
android hooking watch class 类名
这样就可以 hook 这个类里面的所有方法，每次调用都会被 log 出来。 -
android hooking watch class 类名 --dump-args --dump-backtrace --dump-return
在上面的基础上，额外 dump 参数，栈回溯，返回值android hooking watch class xxx.MainActivity --dump-args --dump-backtrace --dump-return -
android hooking watch class_method 方法名//可以直接hook到所有重载 android hooking watch class_method xxx.MainActivity.fun --dump-args --dump-backtrace --dump-returngrep trick 和文件保存
objection log 默认是不能用 grep 过滤的，但是可以通过
objection run xxx | grep yyy的方式，从终端通过管道来过滤。 用法如下sakura@sakuradeMacBook-Pro:~$ objection -g com.android.settings run memory list modules | grep libc Warning: Output is not to a terminal (fd=1). libcutils.so 0x7a94a1c000 81920 (80.0 KiB) /system/lib64/libcutils.so libc++.so 0x7a9114e000 983040 (960.0 KiB) /system/lib64/libc++.so libc.so 0x7a9249d000 892928 (872.0 KiB) /system/lib64/libc.so libcrypto.so 0x7a92283000 1155072 (1.1 MiB) /system/lib64/libcrypto.so有的命令后面可以通过
--json logfile来直接保存结果到文件里。 有的可以通过查看.objection文件里的输出 log 来查看结果。sakura@sakuradeMacBook-Pro:~/.objection$ cat *log | grep -i display android.hardware.display.DisplayManager android.hardware.display.DisplayManager$DisplayListener android.hardware.display.DisplayManagerGlobal
案例学习
案例学习 case1:《仿 VX 数据库原型取证逆向分析》
附件链接
android-backup-extractor 工具链接
sakura@sakuradeMacBook-Pro:~/Desktop/lab/alpha/tools/android/frida_learn$ java -version
java version "1.8.0_141"
sakura@sakuradeMacBook-Pro:~/Desktop/lab/alpha/tools/android/frida_learn$ java -jar abe-all.jar unpack 1.ab 1.tar
0% 1% 2% 3% 4% 5% 6% 7% 8% 9% 10% 11% 12% 13% 14% 15% 16% 17% 18% 19% 20% 21% 22% 23% 24% 25% 26% 27% 28% 29% 30% 31% 32% 33% 34% 35% 36% 37% 38% 39% 40% 41% 42% 43% 44% 45% 46% 47% 48% 49% 50% 51% 52% 53% 54% 55% 56% 57% 58% 59% 60% 61% 62% 63% 64% 65% 66% 67% 68% 69% 70% 71% 72% 73% 74% 75% 76% 77% 78% 79% 80% 81% 82% 83% 84% 85% 86% 87% 88% 89% 90% 91% 92% 93% 94% 95% 96% 97% 98% 99% 100%
9097216 bytes written to 1.tar.
...
sakura@sakuradeMacBook-Pro:~/Desktop/lab/alpha/tools/android/frida_learn/apps/com.example.yaphetshan.tencentwelcome$ ls
Encryto.db _manifest a db
装个夜神模拟器玩
sakura@sakuradeMacBook-Pro:/Applications/NoxAppPlayer.app/Contents/MacOS$ ./adb connect 127.0.0.1:62001
* daemon not running. starting it now on port 5037 *
adb E 5139 141210 usb_osx.cpp:138] Unable to create an interface plug-in (e00002be)
* daemon started successfully *
connected to 127.0.0.1:62001
sakura@sakuradeMacBook-Pro:/Applications/NoxAppPlayer.app/Contents/MacOS$ ./adb shell
dream2qltechn:/ # whoami
root
dream2qltechn:/ # uname -a
Linux localhost 4.0.9+ #222 SMP PREEMPT Sat Mar 14 18:24:36 HKT 2020 i686
肯定还是先定位目标字符串Wait a Minute,What was happend?
jadx 搜索字符串
重点在 a() 代码里，其实是根据明文的 name 和 password，然后aVar.a(a2 + aVar.b(a2, contentValues.getAsString("password"))).substring(0, 7)再做一遍复杂的计算并截取 7 位当做密码，传入 getWritableDatabase 去解密 demo.db 数据库。
所以我们 hook 一下 getWritableDatabase 即可。
frida-ps -U
...
5662 com.example.yaphetshan.tencentwelcome
objection -d -g com.example.yaphetshan.tencentwelcome explore
看一下源码
package net.sqlcipher.database;
...
public abstract class SQLiteOpenHelper {
...
public synchronized SQLiteDatabase getWritableDatabase(char[] cArr) {
也可以 objection search 一下这个 method
...mple.yaphetshan.tencentwelcome on (samsung: 7.1.2) [usb] # android hooking search methods getWritableDatabase
Warning, searching all classes may take some time and in some cases, crash the target application.
Continue? [y/N]: y
Found 4650 classes, searching methods (this may take some time)...
android.database.sqlite.SQLiteOpenHelper.getWritableDatabase
...
net.sqlcipher.database.SQLiteOpenHelper.getWritableDatabase
hook 一下这个 method
[usb] # android hooking watch class_method net.sqlcipher.database.SQLiteOpenHelper.getWritableDatabase --dump-args --dump-backtrace --dump-return
- [incoming message] ------------------
{
"payload": "Attempting to watch class \u001b[32mnet.sqlcipher.database.SQLiteOpenHelper\u001b[39m and method \u001b[32mgetWritableDatabase\u001b[39m.",
"type": "send"
}
- [./incoming message] ----------------
(agent) Attempting to watch class net.sqlcipher.database.SQLiteOpenHelper and method getWritableDatabase.
- [incoming message] ------------------
{
"payload": "Hooking \u001b[32mnet.sqlcipher.database.SQLiteOpenHelper\u001b[39m.\u001b[92mgetWritableDatabase\u001b[39m(\u001b[31mjava.lang.String\u001b[39m)",
"type": "send"
}
- [./incoming message] ----------------
(agent) Hooking net.sqlcipher.database.SQLiteOpenHelper.getWritableDatabase(java.lang.String)
- [incoming message] ------------------
{
"payload": "Hooking \u001b[32mnet.sqlcipher.database.SQLiteOpenHelper\u001b[39m.\u001b[92mgetWritableDatabase\u001b[39m(\u001b[31m[C\u001b[39m)",
"type": "send"
}
- [./incoming message] ----------------
(agent) Hooking net.sqlcipher.database.SQLiteOpenHelper.getWritableDatabase([C)
- [incoming message] ------------------
{
"payload": "Registering job \u001b[94mjytq1qeyllq\u001b[39m. Type: \u001b[92mwatch-method for: net.sqlcipher.database.SQLiteOpenHelper.getWritableDatabase\u001b[39m",
"type": "send"
}
- [./incoming message] ----------------
(agent) Registering job jytq1qeyllq. Type: watch-method for: net.sqlcipher.database.SQLiteOpenHelper.getWritableDatabase
...mple.yaphetshan.tencentwelcome on (samsung: 7.1.2) [usb] #
hook 好之后再打开这个 apk
(agent) [1v488x28gcs] Called net.sqlcipher.database.SQLiteOpenHelper.getWritableDatabase(java.lang.String)
...
(agent) [1v488x28gcs] Backtrace:
net.sqlcipher.database.SQLiteOpenHelper.getWritableDatabase(Native Method)
com.example.yaphetshan.tencentwelcome.MainActivity.a(MainActivity.java:55)
com.example.yaphetshan.tencentwelcome.MainActivity.onCreate(MainActivity.java:42)
android.app.Activity.performCreate(Activity.java:6692)
...
(agent) [1v488x28gcs] Arguments net.sqlcipher.database.SQLiteOpenHelper.getWritableDatabase(ae56f99)
...
...mple.yaphetshan.tencentwelcome on (samsung: 7.1.2) [usb] # jobs list
Job ID Hooks Type
----------- ------- -----------------------------------------------------------------------------
1v488x28gcs 2 watch-method for: net.sqlcipher.database.SQLiteOpenHelper.getWritableDatabase
找到参数ae56f99
剩下的就是用这个密码去打开加密的 db。
然后 base64 解密一下就好了。
还有一种策略是主动调用, 基于数据流的主动调用分析是非常有意思的。 即自己去调用 a 函数以触发 getWritableDatabase 的数据库解密。 先寻找 a 所在类的实例，然后 hook getWritableDatabase，最终主动调用 a。 这里幸运的是 a 没有什么奇奇怪怪的参数需要我们传入，主动调用这种策略在循环注册等地方可能就会有需求 8.
[usb] # android heap search instances com.example.yaphetshan.tencentwelcome.MainActivity
Class instance enumeration complete for com.example.yaphetshan.tencentwelcome.MainActivity
Handle Class toString()
-------- -------------------------------------------------- ----------------------------------------------------------
0x20078a com.example.yaphetshan.tencentwelcome.MainActivity com.example.yaphetshan.tencentwelcome.MainActivity@1528f80
[usb] # android hooking watch class_method net.sqlcipher.database.SQLiteOpenHelper.getWritableDatabase --dump-args --dump-backtrace --dump-return
[usb] # android heap execute 0x20078a a
(agent) [taupgwkum4h] Arguments net.sqlcipher.database.SQLiteOpenHelper.getWritableDatabase(ae56f99)
案例学习 case2: 主动调用爆破密码
因为直接找Unfortunately,note the right PIN :(找不到，可能是把字符串藏在什么资源文件里了。
review 代码之后找到校验的核心函数，逻辑就是将 input 编码一下之后和密码比较，这肯定是什么不可逆的加密。
public static boolean verifyPassword(Context context, String input) {
if (input.length() != 4) {
return false;
}
byte[] v = encodePassword(input);
byte[] p = "09042ec2c2c08c4cbece042681caf1d13984f24a".getBytes();
if (v.length != p.length) {
return false;
}
for (int i = 0; i < v.length; i++) {
if (v[i] != p[i]) {
return false;
}
}
return true;
}
这里就爆破一下密码。
frida-ps -U | grep qualification
7660 org.teamsik.ahe17.qualification.easy
frida -U org.teamsik.ahe17.qualification.easy -l force.js
function main() {
Java.perform(function x() {
console.log("In Java perform")
var verify = Java.use("org.teamsik.ahe17.qualification.Verifier")
var stringClass = Java.use("java.lang.String")
var p = stringClass.$new("09042ec2c2c08c4cbece042681caf1d13984f24a")
var pSign = p.getBytes()
// var pStr = stringClass.$new(pSign)
// console.log(parseInt(pStr))
for (var i = 999; i < 10000; i++){
var v = stringClass.$new(String(i))
var vSign = verify.encodePassword(v)
if (parseInt(stringClass.$new(pSign)) == parseInt(stringClass.$new(vSign))) {
console.log("yes: " + v)
break
}
console.log("not :" + v)
}
})
}
setImmediate(main)
...
not :9080
not :9081
not :9082
yes: 9083
这里注意 parseInt
Frida hook 基础 (一)
- 调用静态函数和调用非静态函数
- 设置 (同名) 成员变量
- 内部类，枚举类的函数并 hook，trace 原型 1
- 查找接口，hook 动态加载 dex
- 枚举 class，trace 原型 2
- objection 不能切换 classloader
Frida hook : 打印参数、返回值 / 设置返回值 / 主动调用
demo 就不贴了，还是先定位登录失败点，然后搜索字符串。
public class LoginActivity extends AppCompatActivity {
/* access modifiers changed from: private */
public Context mContext;
public void onCreate(Bundle bundle) {
super.onCreate(bundle);
this.mContext = this;
setContentView((int) R.layout.activity_login);
final EditText editText = (EditText) findViewById(R.id.username);
final EditText editText2 = (EditText) findViewById(R.id.password);
((Button) findViewById(R.id.login)).setOnClickListener(new View.OnClickListener() {
public void onClick(View view) {
String obj = editText.getText().toString();
String obj2 = editText2.getText().toString();
if (TextUtils.isEmpty(obj) || TextUtils.isEmpty(obj2)) {
Toast.makeText(LoginActivity.this.mContext, "username or password is empty.", 1).show();
} else if (LoginActivity.a(obj, obj).equals(obj2)) {
LoginActivity.this.startActivity(new Intent(LoginActivity.this.mContext, FridaActivity1.class));
LoginActivity.this.finishActivity(0);
} else {
Toast.makeText(LoginActivity.this.mContext, "Login failed.", 1).show();
}
}
});
}
LoginActivity.a(obj, obj).equals(obj2)分析之后可得 obj2 来自 password，由从 username 得来的 obj，经过 a 函数运算之后得到一个值，这两个值相等则登录成功。
所以这里关键是 hook a 函数的参数，最简脚本如下。
//打印参数、返回值
function Login(){
Java.perform(function(){
Java.use("com.example.androiddemo.Activity.LoginActivity").a.overload('java.lang.String', 'java.lang.String').implementation = function (str, str2){
var result = this.a(str, str2);
console.log("args0:"+str+" args1:"+str2+" result:"+result);
return result;
}
})
}
setImmediate(Login)
观察输入和输出, 这里也可以直接主动调用。
function login() {
Java.perform(function () {
console.log("start")
var login = Java.use("com.example.androiddemo.Activity.LoginActivity")
var result = login.a("1234","1234")
console.log(result)
})
}
setImmediate(login)
...
start
4e4feaea959d426155a480dc07ef92f4754ee93edbe56d993d74f131497e66fb
然后
adb shell input text "4e4feaea959d426155a480dc07ef92f4754ee93edbe56d993d74f131497e66fb"
接下来是第一关
public abstract class BaseFridaActivity extends AppCompatActivity implements View.OnClickListener {
public Button mNextCheck;
public void CheckSuccess() {
}
public abstract String getNextCheckTitle();
public abstract void onCheck();
/* access modifiers changed from: protected */
public void onCreate(Bundle bundle) {
super.onCreate(bundle);
setContentView((int) R.layout.activity_frida);
this.mNextCheck = (Button) findViewById(R.id.next_check);
this.mNextCheck.setOnClickListener(this);
Button button = this.mNextCheck;
button.setText(getNextCheckTitle() + "，点击进入下一关");
}
public void onClick(View view) {
onCheck();
}
public void CheckFailed() {
Toast.makeText(this, "Check Failed!", 1).show();
}
}
...
public class FridaActivity1 extends BaseFridaActivity {
private static final char[] table = {'L', 'K', 'N', 'M', 'O', 'Q', 'P', 'R', 'S', 'A', 'T', 'B', 'C', 'E', 'D', 'F', 'G', 'H', 'I', 'J', 'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'o', 'd', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'e', 'f', 'g', 'h', 'j', 'i', 'k', 'l', 'm', 'n', 'y', 'z', '0', '1', '2', '3', '4', '6', '5', '7', '8', '9', '+', '/'};
public String getNextCheckTitle() {
return "当前第1关";
}
public void onCheck() {
try {
if (a(b("请输入密码:")).equals("R4jSLLLLLLLLLLOrLE7/5B+Z6fsl65yj6BgC6YWz66gO6g2t65Pk6a+P65NK44NNROl0wNOLLLL=")) {
CheckSuccess();
startActivity(new Intent(this, FridaActivity2.class));
finishActivity(0);
return;
}
super.CheckFailed();
} catch (Exception e) {
e.printStackTrace();
}
}
public static String a(byte[] bArr) throws Exception {
StringBuilder sb = new StringBuilder();
for (int i = 0; i <= bArr.length - 1; i += 3) {
byte[] bArr2 = new byte[4];
byte b = 0;
for (int i2 = 0; i2 <= 2; i2++) {
int i3 = i + i2;
if (i3 <= bArr.length - 1) {
bArr2[i2] = (byte) (b | ((bArr[i3] & 255) >>> ((i2 * 2) + 2)));
b = (byte) ((((bArr[i3] & 255) << (((2 - i2) * 2) + 2)) & 255) >>> 2);
} else {
bArr2[i2] = b;
b = 64;
}
}
bArr2[3] = b;
for (int i4 = 0; i4 <= 3; i4++) {
if (bArr2[i4] <= 63) {
sb.append(table[bArr2[i4]]);
} else {
sb.append('=');
}
}
}
return sb.toString();
}
public static byte[] b(String str) {
try {
ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
GZIPOutputStream gZIPOutputStream = new GZIPOutputStream(byteArrayOutputStream);
gZIPOutputStream.write(str.getBytes());
gZIPOutputStream.finish();
gZIPOutputStream.close();
byte[] byteArray = byteArrayOutputStream.toByteArray();
try {
byteArrayOutputStream.close();
return byteArray;
} catch (Exception e) {
e.printStackTrace();
return byteArray;
}
} catch (Exception unused) {
return null;
}
}
}
关键函数在a(b("请输入密码:")).equals("R4jSLLLLLLLLLLOrLE7/5B+Z6fsl65yj6BgC6YWz66gO6g2t65Pk6a+P65NK44NNROl0wNOLLLL=")
这里应该直接 hook a，让其返回值为R4jSLLLLLLLLLLOrLE7/5B+Z6fsl65yj6BgC6YWz66gO6g2t65Pk6a+P65NK44NNROl0wNOLLLL=就可以进入下一关了。
function ch1() {
Java.perform(function () {
console.log("start")
Java.use("com.example.androiddemo.Activity.FridaActivity1").a.implementation = function (x) {
return "R4jSLLLLLLLLLLOrLE7/5B+Z6fsl65yj6BgC6YWz66gO6g2t65Pk6a+P65NK44NNROl0wNOLLLL="
}
})
}
Frida hook : 主动调用静态 / 非静态函数 以及 设置静态 / 非静态成员变量的值
总结:
- 静态函数直接 use class 然后调用方法，非静态函数需要先 choose 实例然后调用
- 设置成员变量的值，写法是
xx.value = yy，其他方面和函数一样。 - 如果有一个成员变量和成员函数的名字相同，则在其前面加一个
_，如_xx.value = yy
然后是第二关
public class FridaActivity2 extends BaseFridaActivity {
private static boolean static_bool_var = false;
private boolean bool_var = false;
public String getNextCheckTitle() {
return "当前第2关";
}
private static void setStatic_bool_var() {
static_bool_var = true;
}
private void setBool_var() {
this.bool_var = true;
}
public void onCheck() {
if (!static_bool_var || !this.bool_var) {
super.CheckFailed();
return;
}
CheckSuccess();
startActivity(new Intent(this, FridaActivity3.class));
finishActivity(0);
}
}
这一关的关键在于下面的 if 判断要为 false，则static_bool_var和this.bool_var都要为 true。
if (!static_bool_var || !this.bool_var) {
super.CheckFailed();
return;
}
这样就要调用setBool_var和setStatic_bool_var两个函数了。
function ch2() {
Java.perform(function () {
console.log("start")
var FridaActivity2 = Java.use("com.example.androiddemo.Activity.FridaActivity2")
//hook静态函数直接调用
FridaActivity2.setStatic_bool_var()
//hook动态函数，找到instance实例，从实例调用函数方法
Java.choose("com.example.androiddemo.Activity.FridaActivity2", {
onMatch: function (instance) {
instance.setBool_var()
},
onComplete: function () {
console.log("end")
}
})
})
}
setImmediate(ch2)
接下来是第三关
public class FridaActivity3 extends BaseFridaActivity {
private static boolean static_bool_var = false;
private boolean bool_var = false;
private boolean same_name_bool_var = false;
public String getNextCheckTitle() {
return "当前第3关";
}
private void same_name_bool_var() {
Log.d("Frida", static_bool_var + " " + this.bool_var + " " + this.same_name_bool_var);
}
public void onCheck() {
if (!static_bool_var || !this.bool_var || !this.same_name_bool_var) {
super.CheckFailed();
return;
}
CheckSuccess();
startActivity(new Intent(this, FridaActivity4.class));
finishActivity(0);
}
}
关键还是让if (!static_bool_var || !this.bool_var || !this.same_name_bool_var)为 false，则三个变量都要为 true
function ch3() {
Java.perform(function () {
console.log("start")
var FridaActivity3 = Java.use("com.example.androiddemo.Activity.FridaActivity3")
FridaActivity3.static_bool_var.value = true
Java.choose("com.example.androiddemo.Activity.FridaActivity3", {
onMatch: function (instance) {
instance.bool_var.value = true
instance._same_name_bool_var.value = true
},
onComplete: function () {
console.log("end")
}
})
})
}
这里要注意类里有一个成员函数和成员变量都叫做same_name_bool_var，这种时候在成员变量前加一个_，修改值的形式为xx.value = yy
Frida hook : 内部类，枚举类的函数并 hook，trace 原型 1
总结:
- 对于内部类，通过
类名$内部类名去 use 或者 choose - 对 use 得到的 clazz 应用反射，如
clazz.class.getDeclaredMethods()可以得到类里面声明的所有方法，即可以枚举类里面的所有函数。
接下来是第四关
public class FridaActivity4 extends BaseFridaActivity {
public String getNextCheckTitle() {
return "当前第4关";
}
private static class InnerClasses {
public static boolean check1() {
return false;
}
public static boolean check2() {
return false;
}
public static boolean check3() {
return false;
}
public static boolean check4() {
return false;
}
public static boolean check5() {
return false;
}
public static boolean check6() {
return false;
}
private InnerClasses() {
}
}
public void onCheck() {
if (!InnerClasses.check1() || !InnerClasses.check2() || !InnerClasses.check3() || !InnerClasses.check4() || !InnerClasses.check5() || !InnerClasses.check6()) {
super.CheckFailed();
return;
}
CheckSuccess();
startActivity(new Intent(this, FridaActivity5.class));
finishActivity(0);
}
}
这一关的关键是让if (!InnerClasses.check1() || !InnerClasses.check2() || !InnerClasses.check3() || !InnerClasses.check4() || !InnerClasses.check5() || !InnerClasses.check6())中的所有 check 全部返回 true。
其实这里唯一的问题就是寻找内部类InnerClasses，对于内部类的 hook，通过类名$内部类名去 use。
function ch4() {
Java.perform(function () {
var InnerClasses = Java.use("com.example.androiddemo.Activity.FridaActivity4$InnerClasses")
console.log("start")
InnerClasses.check1.implementation = function () {
return true
}
InnerClasses.check2.implementation = function () {
return true
}
InnerClasses.check3.implementation = function () {
return true
}
InnerClasses.check4.implementation = function () {
return true
}
InnerClasses.check5.implementation = function () {
return true
}
InnerClasses.check6.implementation = function () {
return true
}
})
}
利用反射，获取类中的所有 method 声明，然后字符串拼接去获取到方法名，例如下面的 check1，然后就可以批量 hook，而不用像我上面那样一个一个写。
var inner_classes = Java.use("com.example.androiddemo.Activity.FridaActivity4$InnerClasses")
var all_methods = inner_classes.class.getDeclaredMethods();
...
public static boolean com.example.androiddemo.Activity.FridaActivity4$InnerClasses.check1(),public static boolean com.example.androiddemo.Activity.FridaActivity4$InnerClasses.check2(),public static boolean com.example.androiddemo.Activity.FridaActivity4$InnerClasses.check3(),public static boolean com.example.androiddemo.Activity.FridaActivity4$InnerClasses.check4(),public static boolean com.example.androiddemo.Activity.FridaActivity4$InnerClasses.check5(),public static boolean com.example.androiddemo.Activity.FridaActivity4$InnerClasses.check6()
Frida hook : hook 动态加载的 dex，与查找 interface，
总结:
- 通过
enumerateClassLoaders来枚举加载进内存的 classloader，再loader.findClass(xxx)寻找是否包括我们想要的 interface 的实现类，最后通过Java.classFactory.loader = loader来切换 classloader，从而加载该实现类。
第五关比较有趣，它的 check 函数是动态加载进来的。 java 里有 interface 的概念，是指一系列抽象的接口，需要类来实现。
package com.example.androiddemo.Dynamic;
public interface CheckInterface {
boolean check();
}
...
public class DynamicCheck implements CheckInterface {
public boolean check() {
return false;
}
}
...
public class FridaActivity5 extends BaseFridaActivity {
private CheckInterface DynamicDexCheck = null;
...
public CheckInterface getDynamicDexCheck() {
if (this.DynamicDexCheck == null) {
loaddex();
}
return this.DynamicDexCheck;
}
/* access modifiers changed from: protected */
public void onCreate(Bundle bundle) {
super.onCreate(bundle);
loaddex();
//this.DynamicDexCheck = (CheckInterface) new DexClassLoader(str, filesDir.getAbsolutePath(), (String) null, getClassLoader()).loadClass("com.example.androiddemo.Dynamic.DynamicCheck").newInstance();
}
public void onCheck() {
if (getDynamicDexCheck() == null) {
Toast.makeText(this, "onClick loaddex Failed!", 1).show();
} else if (getDynamicDexCheck().check()) {
CheckSuccess();
startActivity(new Intent(this, FridaActivity6.class));
finishActivity(0);
} else {
super.CheckFailed();
}
}
}
这里有个 loaddex 其实就是先从资源文件加载 classloader 到内存里，再 loadClass DynamicCheck，创建出一个实例，最终调用这个实例的 check。
所以现在我们就要先枚举 class loader，找到能实例化我们要的 class 的那个 class loader，然后把它设置成 Java 的默认 class factory 的 loader。
现在就可以用这个 class loader 来使用.use去 import 一个给定的类。
function ch5() {
Java.perform(function () {
// Java.choose("com.example.androiddemo.Activity.FridaActivity5",{
// onMatch:function(x){
// console.log(x.getDynamicDexCheck().$className)
// },onComplete:function(){}
// })
console.log("start")
Java.enumerateClassLoaders({
onMatch: function (loader) {
try {
if(loader.findClass("com.example.androiddemo.Dynamic.DynamicCheck")){
console.log("Successfully found loader")
console.log(loader);
Java.classFactory.loader = loader ;
}
}
catch(error){
console.log("find error:" + error)
}
},
onComplete: function () {
console.log("end1")
}
})
Java.use("com.example.androiddemo.Dynamic.DynamicCheck").check.implementation = function () {
return true
}
console.log("end2")
})
}
setImmediate(ch5)
todo 有一个疑问
https://github.com/frida/frida/issues/1049
Frida hook : 枚举 class，trace 原型 2
总结: 通过Java.enumerateLoadedClasses来枚举类，然后name.indexOf(str)过滤一下并 hook。
接下来是第六关
import com.example.androiddemo.Activity.Frida6.Frida6Class0;
import com.example.androiddemo.Activity.Frida6.Frida6Class1;
import com.example.androiddemo.Activity.Frida6.Frida6Class2;
public class FridaActivity6 extends BaseFridaActivity {
public String getNextCheckTitle() {
return "当前第6关";
}
public void onCheck() {
if (!Frida6Class0.check() || !Frida6Class1.check() || !Frida6Class2.check()) {
super.CheckFailed();
return;
}
CheckSuccess();
startActivity(new Intent(this, FridaActivity7.class));
finishActivity(0);
}
}
这关是 import 了一些类，然后调用类里的静态方法，所以我们枚举所有的类，然后过滤一下，并把过滤出来的结果 hook 上，改掉其返回值。
function ch6() {
Java.perform(function () {
Java.enumerateLoadedClasses({
onMatch: function (name, handle){
if (name.indexOf("com.example.androiddemo.Activity.Frida6") != -1) {
console.log("name:" + name + " handle:" + handle)
Java.use(name).check.implementation = function () {
return true
}
}
},
onComplete: function () {
console.log("end")
}
})
})
}
Frida hook : 搜索 interface 的具体实现类
利用反射得到类里面实现的 interface 数组，并打印出来。
function more() {
Java.perform(function () {
Java.enumerateLoadedClasses({
onMatch: function (class_name){
if (class_name.indexOf("com.example.androiddemo") < 0) {
return
}
else {
var hook_cls = Java.use(class_name)
var interfaces = hook_cls.class.getInterfaces()
if (interfaces.length > 0) {
console.log(class_name + ": ")
for (var i in interfaces) {
console.log("\t", interfaces[i].toString())
}
}
}
},
onComplete: function () {
console.log("end")
}
})
})
}
Frida hook 基础（二)
- spawn/attach
- 各种主动调用
- hook 函数和 hook 构造函数
- 调用栈 / 简单脚本
- 动态加载自己的 dex
题目下载地址:
https://github.com/tlamb96/kgb_messenger
spawn/attach
firda 的 - f 参数代表 span 启动
frida -U -f com.tlamb96.spetsnazmessenger -l frida_russian.js --no-pause
/* access modifiers changed from: protected */
public void onCreate(Bundle bundle) {
super.onCreate(bundle);
setContentView((int) R.layout.activity_main);
String property = System.getProperty("user.home");
String str = System.getenv("USER");
if (property == null || property.isEmpty() || !property.equals("Russia")) {
a("Integrity Error", "This app can only run on Russian devices.");
} else if (str == null || str.isEmpty() || !str.equals(getResources().getString(R.string.User))) {
a("Integrity Error", "Must be on the user whitelist.");
} else {
a.a(this);
startActivity(new Intent(this, LoginActivity.class));
}
}
}
这个题目比较简单，但是因为这个 check 是在onCreate里，所以 app 刚启动就自动检查，所以这里需要用 spawn 的方式去启动 frida 脚本 hook，而不是 attach。
这里有两个检查，一个是检查 property 的值，一个是检查 str 的值。
分别从System.getProperty和System.getenv里获取，hook 住这两个函数就行。
这里要注意从资源文件里找到User的值。
function main() {
Java.perform(function () {
Java.use("java.lang.System").getProperty.overload('java.lang.String').implementation = function (str) {
return "Russia";
}
Java.use("java.lang.System").getenv.overload('java.lang.String').implementation = function(str){
return "RkxBR3s1N0VSTDFOR180UkNIM1J9Cg==";
}
})
}
setImmediate(main)
接下来进入到 login 功能
public void onLogin(View view) {
EditText editText = (EditText) findViewById(R.id.login_username);
EditText editText2 = (EditText) findViewById(R.id.login_password);
this.n = editText.getText().toString();
this.o = editText2.getText().toString();
if (this.n != null && this.o != null && !this.n.isEmpty() && !this.o.isEmpty()) {
if (!this.n.equals(getResources().getString(R.string.username))) {
Toast.makeText(this, "User not recognized.", 0).show();
editText.setText("");
editText2.setText("");
} else if (!j()) {
Toast.makeText(this, "Incorrect password.", 0).show();
editText.setText("");
editText2.setText("");
} else {
i();
startActivity(new Intent(this, MessengerActivity.class));
}
}
}
...
private boolean j() {
String str = "";
for (byte b : this.m.digest(this.o.getBytes())) {
str = str + String.format("%x", new Object[]{Byte.valueOf(b)});
}
return str.equals(getResources().getString(R.string.password));
}
...
private void i() {
char[] cArr = {'(', 'W', 'D', ')', 'T', 'P', ':', '#', '?', 'T'};
cArr[0] = (char) (cArr[0] ^ this.n.charAt(1));
cArr[1] = (char) (cArr[1] ^ this.o.charAt(0));
cArr[2] = (char) (cArr[2] ^ this.o.charAt(4));
cArr[3] = (char) (cArr[3] ^ this.n.charAt(4));
cArr[4] = (char) (cArr[4] ^ this.n.charAt(7));
cArr[5] = (char) (cArr[5] ^ this.n.charAt(0));
cArr[6] = (char) (cArr[6] ^ this.o.charAt(2));
cArr[7] = (char) (cArr[7] ^ this.o.charAt(3));
cArr[8] = (char) (cArr[8] ^ this.n.charAt(6));
cArr[9] = (char) (cArr[9] ^ this.n.charAt(8));
Toast.makeText(this, "FLAG{" + new String(cArr) + "}", 1).show();
}
从资源文件里找到 username, 密码则是要算一个 j() 函数，要让它返回 true，顺便打印一下 i 函数 toast 到界面的 flag。
Java.use("com.tlamb96.kgbmessenger.LoginActivity").j.implementation = function () {
return true
}
...
Java.use("android.widget.Toast").makeText.overload('android.content.Context', 'java.lang.CharSequence', 'int').implementation = function (x, y, z) {
var flag = Java.use("java.lang.String").$new(y)
console.log(flag)
}
...
[Google Pixel::com.tlamb96.spetsnazmessenger]-> FLAG{G&qG13 R0}
Frida hook :hook 构造函数 / 打印栈回溯
总结:
hook 构造函数实现通过 use 取得类，然后clazz.$init.implementation = callback hook 构造函数。
我们先学习一下怎么 hook 构造函数。
add(new com.tlamb96.kgbmessenger.b.a(R.string.katya, "Archer, you up?", "2:20 am", true));
...
package com.tlamb96.kgbmessenger.b;
public class a {
...
public a(int i, String str, String str2, boolean z) {
this.f448a = i;
this.b = str;
this.c = str2;
this.d = z;
}
...
}
用$init来 hook 构造函数
Java.use("com.tlamb96.kgbmessenger.b.a").$init.implementation = function (i, str1, str2, z) {
this.$init(i, str1, str2, z)
console.log(i, str1, str2, z)
printStack("com.tlamb96.kgbmessenger.b.a")
}
Frida hook : 打印栈回溯
打印栈回溯
function printStack(name) {
Java.perform(function () {
var Exception = Java.use("java.lang.Exception");
var ins = Exception.$new("Exception");
var straces = ins.getStackTrace();
if (straces != undefined && straces != null) {
var strace = straces.toString();
var replaceStr = strace.replace(/,/g, "\\n");
console.log("=============================" + name + " Stack strat=======================");
console.log(replaceStr);
console.log("=============================" + name + " Stack end=======================\r\n");
Exception.$dispose();
}
});
}
输出就是这样
[Google Pixel::com.tlamb96.spetsnazmessenger]-> 2131558449 111 02:27 下午 false
=============================com.tlamb96.kgbmessenger.b.a Stack strat=======================
com.tlamb96.kgbmessenger.b.a.<init>(Native Method)
com.tlamb96.kgbmessenger.MessengerActivity.onSendMessage(Unknown Source:40)
java.lang.reflect.Method.invoke(Native Method)
android.support.v7.app.m$a.onClick(Unknown Source:25)
android.view.View.performClick(View.java:6294)
android.view.View$PerformClick.run(View.java:24770)
android.os.Handler.handleCallback(Handler.java:790)
android.os.Handler.dispatchMessage(Handler.java:99)
android.os.Looper.loop(Looper.java:164)
android.app.ActivityThread.main(ActivityThread.java:6494)
java.lang.reflect.Method.invoke(Native Method)
com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438)
com.android.internal.os.ZygoteInit.main(ZygoteInit.java:807)
=============================com.tlamb96.kgbmessenger.b.a Stack end=======================
Frida hook : 手动加载 dex 并调用
总结：
编译出 dex 之后，通过Java.openClassFile("xxx.dex").load()加载，这样我们就可以正常通过Java.use调用里面的方法了。
现在我们来继续解决这个问题。
public void onSendMessage(View view) {
EditText editText = (EditText) findViewById(R.id.edittext_chatbox);
String obj = editText.getText().toString();
if (!TextUtils.isEmpty(obj)) {
this.o.add(new com.tlamb96.kgbmessenger.b.a(R.string.user, obj, j(), false));
this.n.c();
if (a(obj.toString()).equals(this.p)) {
Log.d("MessengerActivity", "Successfully asked Boris for the password.");
this.q = obj.toString();
this.o.add(new com.tlamb96.kgbmessenger.b.a(R.string.boris, "Only if you ask nicely", j(), true));
this.n.c();
}
if (b(obj.toString()).equals(this.r)) {
Log.d("MessengerActivity", "Successfully asked Boris nicely for the password.");
this.s = obj.toString();
this.o.add(new com.tlamb96.kgbmessenger.b.a(R.string.boris, "Wow, no one has ever been so nice to me! Here you go friend: FLAG{" + i() + "}", j(), true));
this.n.c();
}
this.m.b(this.m.getAdapter().a() - 1);
editText.setText("");
}
}
新的一关是一个聊天框，分析一下代码可知，obj 是我们输入的内容，输入完了之后，加到一个this.o的 ArrayList 里。
关键的 if 判断就是if (a(obj.toString()).equals(this.p))和if (b(obj.toString()).equals(this.r))，所有 hook a 和 b 函数，让它们的返回值等于下面的字符串即可。
private String p = "V@]EAASB\u0012WZF\u0012e,a$7(&am2(3.\u0003";
private String q;
private String r = "\u0000dslp}oQ\u0000 dks$|M\u0000h +AYQg\u0000P*!M$gQ\u0000";
private String s;
但实际上这题比我想象中的还要麻烦，这题的逻辑上是如果通过了 a 和 b 这两个函数的计算，等于对应的值之后，会把用来计算的 obj 的值赋值给 q 和 s，然后根据这个 q 和 s 来计算出最终的 flag。 所以如果不逆向算法，通过 hook 的方式通过了 a 和 b 的计算，obj 的值还是错误的，也计算不出正确的 flag。
这样就逆向一下算法好了，先自己写一个 apk，用 java 去实现注册机。
可以直接把 class 文件转成 dex，不复述，我比较懒，所以我直接解压 apk 找到classes.dex，并 push 到手机上。
然后用 frida 加载这个 dex，并调用里面的方法。
var dex = Java.openClassFile("/data/local/tmp/classes.dex").load();
console.log("decode_P:"+Java.use("myapplication.example.com.reversea.reverseA").decode_P());
console.log("r_to_hex:"+Java.use("myapplication.example.com.reversea.reverseA").r_to_hex());
...
...
decode_P:Boris, give me the password
r_to_hex:0064736c707d6f510020646b73247c4d0068202b4159516700502a214d24675100
Frida 打印与参数构造
-
数组 /(字符串) 对象数组 / gson/Java.array
-
对象 / 多态、强转 Java.cast / 接口 Java.register
-
泛型、List、Map、Set、迭代打印
-
non-ascii 、 child-gating、rpc 上传到 PC 上打印
char[]/[Object Object]
Log.d("SimpleArray", "onCreate: SImpleArray"); char arr[][] = new char[4][]; // 创建一个4行的二维数组 arr[0] = new char[] { '春', '眠', '不', '觉', '晓' }; // 为每一行赋值 arr[1] = new char[] { '处', '处', '闻', '啼', '鸟' }; arr[2] = new char[] { '夜', '来', '风', '雨', '声' }; arr[3] = new char[] { '花', '落', '知', '多', '少' }; Log.d("SimpleArray", "-----横版-----"); for (int i = 0; i < 4; i++) { // 循环4行 Log.d("SimpleArraysToString", Arrays.toString(arr[i])); Log.d("SimpleStringBytes", Arrays.toString (Arrays.toString (arr[i]).getBytes())); for (int j = 0; j < 5; j++) { // 循环5列 Log.d("SimpleArray", Character.toString(arr[i][j])); // 输出数组中的元素 } if (i % 2 == 0) { Log.d("SimpleArray", ",");// 如果是一、三句，输出逗号 } else { Log.d("SimpleArray", "。");// 如果是二、四句，输出句号 } }Java.openClassFile("/data/local/tmp/r0gson.dex").load(); const gson = Java.use('com.r0ysue.gson.Gson'); Java.use("java.lang.Character").toString.overload('char').implementation = function(char){ var result = this.toString(char); console.log("char,result",char,result); return result; } Java.use("java.util.Arrays").toString.overload('[C').implementation = function(charArray){ var result = this.toString(charArray); console.log("charArray,result:",charArray,result) console.log("charArray Object Object:",gson.$new().toJson(charArray)); return result; }这里的
[C是 JNI 函数签名
byte[]
Java.openClassFile("/data/local/tmp/r0gson.dex").load();
const gson = Java.use('com.r0ysue.gson.Gson');
Java.use("java.util.Arrays").toString.overload('[B').implementation = function(byteArray){
var result = this.toString(byteArray);
console.log("byteArray,result):",byteArray,result)
console.log("byteArray Object Object:",gson.$new().toJson(byteArray));
return result;
}
java array 构造
如果不只是想打印出结果，而是要替换原本的参数，就要先自己构造出一个 charArray, 使用Java.arrayAPI
/**
* Creates a Java array with elements of the specified `type`, from a
* JavaScript array `elements`. The resulting Java array behaves like
* a JS array, but can be passed by reference to Java APIs in order to
* allow them to modify its contents.
*
* @param type Type name of elements.
* @param elements Array of JavaScript values to use for constructing the
* Java array.
*/
function array(type: string, elements: any[]): any[];
Java.use("java.util.Arrays").toString.overload('[C').implementation = function(charArray){
var newCharArray = Java.array('char', [ '一','去','二','三','里' ]);
var result = this.toString(newCharArray);
console.log("newCharArray,result:",newCharArray,result)
console.log("newCharArray Object Object:",gson.$new().toJson(newCharArray));
var newResult = Java.use('java.lang.String').$new(Java.array('char', [ '烟','村','四','五','家']))
return newResult;
}
可以用来构造参数重发包，用在爬虫上。
类的多态：转型 / Java.cast
可以通过getClass().getName().toString()来查看当前实例的类型。
找到一个 instance，通过Java.cast来强制转换对象的类型。
/**
* Creates a JavaScript wrapper given the existing instance at `handle` of
* given class `klass` as returned from `Java.use()`.
*
* @param handle An existing wrapper or a JNI handle.
* @param klass Class wrapper for type to cast to.
*/
function cast(handle: Wrapper | NativePointerValue, klass: Wrapper): Wrapper;
public class Water { // 水 类
public static String flow(Water W) { // 水 的方法
// SomeSentence
Log.d("2Object", "water flow: I`m flowing");
return "water flow: I`m flowing";
}
public String still(Water W) { // 水 的方法
// SomeSentence
Log.d("2Object", "water still: still water runs deep!");
return "water still: still water runs deep!";
}
}
...
public class Juice extends Water { // 果汁 类 继承了水类
public String fillEnergy(){
Log.d("2Object", "Juice: i`m fillingEnergy!");
return "Juice: i`m fillingEnergy!";
}
var JuiceHandle = null ;
Java.choose("com.r0ysue.a0526printout.Juice",{
onMatch:function(instance){
console.log("found juice instance",instance);
console.log("juice instance call fill",instance.fillEnergy());
JuiceHandle = instance;
},onComplete:function(){
console.log("juice handle search completed!")
}
})
console.log("Saved juice handle :",JuiceHandle);
var WaterHandle = Java.cast(JuiceHandle,Java.use("com.r0ysue.a0526printout.Water"))
console.log("call Waterhandle still method:",WaterHandle.still(WaterHandle));
interface/Java.registerClass
public interface liquid {
public String flow();
}
frida 提供能力去创建一个新的 java class
/**
* Creates a new Java class.
*
* @param spec Object describing the class to be created.
*/
function registerClass(spec: ClassSpec): Wrapper;
首先获取要实现的 interface，然后调用 registerClass 来实现 interface。
Java.perform(function(){
var liquid = Java.use("com.r0ysue.a0526printout.liquid");
var beer = Java.registerClass({
name: 'com.r0ysue.a0526printout.beer',
implements: [liquid],
methods: {
flow: function () {
console.log("look, beer is flowing!")
return "look, beer is flowing!";
}
}
});
console.log("beer.bubble:",beer.$new().flow())
})
}
成员内部类 / 匿名内部类
看 smali 或者枚举出来的类。
hook enum
关于 java 枚举，从这篇文章了解。 https://www.cnblogs.com/jingmoxukong/p/6098351.html
enum Signal {
GREEN, YELLOW, RED
}
public class TrafficLight {
public static Signal color = Signal.RED;
public static void main() {
Log.d("4enum", "enum "+ color.getClass().getName().toString());
switch (color) {
case RED:
color = Signal.GREEN;
break;
case YELLOW:
color = Signal.RED;
break;
case GREEN:
color = Signal.YELLOW;
break;
}
}
}
Java.perform(function(){
Java.choose("com.r0ysue.a0526printout.Signal",{
onMatch:function(instance){
console.log("instance.name:",instance.name());
console.log("instance.getDeclaringClass:",instance.getDeclaringClass());
},onComplete:function(){
console.log("search completed!")
}
})
})
打印 hash map
Java.perform(function(){
Java.choose("java.util.HashMap",{
onMatch:function(instance){
if(instance.toString().indexOf("ISBN")!= -1){
console.log("instance.toString:",instance.toString());
}
},onComplete:function(){
console.log("search complete!")
}
})
})
打印 non-ascii
https://api-caller.com/2019/03/30/frida-note/#non-ascii
类名非 ASCII 字符串时，先编码打印出来, 再用编码后的字符串去 hook.
//场景hook cls.forName寻找目标类的classloader。
cls.forName.overload('java.lang.String', 'boolean', 'java.lang.ClassLoader').implementation = function (arg1, arg2, arg3) {
var clsName = cls.forName(arg1, arg2, arg3);
console.log('oriClassName:' + arg1)
var base64Name = encodeURIComponent(arg1)
console.log('encodeName:' + base64Name);
//通过日志确认base64后的非ascii字符串，下面对比并打印classloader
//clsName为特殊字符o.ÎÉ«
if ('o.%CE%99%C9%AB' == base64Name) {
//打印classloader
console.log(arg3);
}
return clsName;
}
Frida native hook : NDK 开发入门
https://www.jianshu.com/p/87ce6f565d37
Frida native hook : JNIEnv 和反射
以 jni 字符串来掌握基本的 JNIEnv 用法
public native String stringWithJNI(String context);
...
extern "C"
JNIEXPORT jstring JNICALL
Java_myapplication_example_com_ndk_1demo_MainActivity_stringWithJNI(JNIEnv *env, jobject instance,
jstring context_) {
const char *context = env->GetStringUTFChars(context_, 0);
int context_size = env->GetStringUTFLength(context_);
if (context_size > 0) {
LOGD("%s\n", context);
}
env->ReleaseStringUTFChars(context_, context);
return env->NewStringUTF("sakura1328");
}
12-26 22:30:00.548 15764-15764/myapplication.example.com.ndk_demo D/sakura1328: sakura
Java 反射
总结: 多去读一下 java 的反射 API。
- 查找调用各种 API 接口、JNI、frida/xposed 原理的一部分
- 反射基本 API
- 反射修改访问控制、修改属性值
- JNI so 调用反射进入 java 世界
- xposed/Frida hook 原理
这里其实有一个伏笔，就是为什么我们要 trace artmethod，hook artmethod 是因为有些 so 混淆得非常厉害，然后也就很难静态分析看出 so 里面调用了哪些 java 函数，也不是通过类似 JNI 的 GetMethodID 这样来调用的。 而是通过类似 findclass 这种方法先得到类，然后再反射调用 app 里面的某个 java 函数。
所以去 hook 它执行的位置，每一个 java 函数对于 Android 源码而言都是一个 artmethod 结构体，然后 hook 拿到 artmethod 实例以后调用类函数，打印这个函数的名称。
public class MainActivity extends AppCompatActivity {
private static final String TAG = "sakura";
// Used to load the 'native-lib' library on application startup.
static {
System.loadLibrary("native-lib");
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Example of a call to a native method
TextView tv = (TextView) findViewById(R.id.sample_text);
tv.setText(stringWithJNI("sakura"));
// Log.d(TAG, stringFromJNI());
// Log.d(TAG, stringWithJNI("sakura"));
try {
testClass();
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (NoSuchFieldException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (NoSuchMethodException e) {
e.printStackTrace();
} catch (InvocationTargetException e) {
e.printStackTrace();
}
}
public void testClass() throws ClassNotFoundException, NoSuchFieldException, IllegalAccessException, NoSuchMethodException, InvocationTargetException {
Test sakuraTest = new Test();
// 获得Class的方法（三种）
Class testClazz = MainActivity.class.getClassLoader().loadClass("myapplication.example.com.ndk_demo.Test");
Class testClazz2 = Class.forName("myapplication.example.com.ndk_demo.Test");
Class testClazz3 = Test.class;
Log.i(TAG, "Classloader.loadClass->" + testClazz);
Log.i(TAG, "Classloader.loadClass->" + testClazz2);
Log.i(TAG, "Classloader.loadClass->" + testClazz3.getName());
// 获得类中属性相关的方法
Field publicStaticField = testClazz3.getDeclaredField("publicStaticField");
Log.i(TAG, "testClazz3.getDeclaredField->" + publicStaticField);
Field publicField = testClazz3.getDeclaredField("publicField");
Log.i(TAG, "testClazz3.getDeclaredField->" + publicField);
//对于Field的get方法，如果是static，则传入null即可;如果不是，则需要传入一个类的实例
String valueStaticPublic = (String) publicStaticField.get(null);
Log.i(TAG, "publicStaticField.get->" + valueStaticPublic);
String valuePublic = (String) publicField.get(sakuraTest);
Log.i(TAG, "publicField.get->" + valuePublic);
//对于private属性，需要设置Accessible
Field privateStaticField = testClazz3.getDeclaredField("privateStaticField");
privateStaticField.setAccessible(true);
String valuePrivte = (String) privateStaticField.get(null);
Log.i(TAG, "modified before privateStaticField.get->" + valuePrivte);
privateStaticField.set(null, "modified");
valuePrivte = (String) privateStaticField.get(null);
Log.i(TAG, "modified after privateStaticField.get->" + valuePrivte);
Field[] fields = testClazz3.getDeclaredFields();
for (Field i : fields) {
Log.i(TAG, "testClazz3.getDeclaredFields->" + i);
}
// 获得类中method相关的方法
Method publicStaticMethod = testClazz3.getDeclaredMethod("publicStaticFunc");
Log.i(TAG, "testClazz3.getDeclaredMethod->" + publicStaticMethod);
publicStaticMethod.invoke(null);
Method publicMethod = testClazz3.getDeclaredMethod("publicFunc", java.lang.String.class);
Log.i(TAG, "testClazz3.getDeclaredMethod->" + publicMethod);
publicMethod.invoke(sakuraTest, " sakura");
}
/**
* A native method that is implemented by the 'native-lib' native library,
* which is packaged with this application.
*/
public native String stringFromJNI();
public native String stringWithJNI(String context);
}
...
public class Test {
private static final String TAG = "sakura_test";
public static String publicStaticField = "i am a publicStaticField";
public String publicField = "i am a publicField";
private static String privateStaticField = "i am a privateStaticField";
private String privateField = "i am a privateField";
public static void publicStaticFunc() {
Log.d(TAG, "I`m from publicStaticFunc");
}
public void publicFunc(String str) {
Log.d(TAG, "I`m from publicFunc" + str);
}
private static void privateStaticFunc() {
Log.i(TAG, "I`m from privateFunc");
}
private void privateFunc() {
Log.i(TAG, "I`m from privateFunc");
}
}
...
...
12-26 23:57:11.784 17682-17682/myapplication.example.com.ndk_demo I/sakura: Classloader.loadClass->class myapplication.example.com.ndk_demo.Test
12-26 23:57:11.784 17682-17682/myapplication.example.com.ndk_demo I/sakura: Classloader.loadClass->class myapplication.example.com.ndk_demo.Test
12-26 23:57:11.784 17682-17682/myapplication.example.com.ndk_demo I/sakura: Classloader.loadClass->myapplication.example.com.ndk_demo.Test
12-26 23:57:11.785 17682-17682/myapplication.example.com.ndk_demo I/sakura: testClazz3.getDeclaredField->public static java.lang.String myapplication.example.com.ndk_demo.Test.publicStaticField
12-26 23:57:11.785 17682-17682/myapplication.example.com.ndk_demo I/sakura: testClazz3.getDeclaredField->public java.lang.String myapplication.example.com.ndk_demo.Test.publicField
12-26 23:57:11.785 17682-17682/myapplication.example.com.ndk_demo I/sakura: publicStaticField.get->i am a publicStaticField
12-26 23:57:11.785 17682-17682/myapplication.example.com.ndk_demo I/sakura: publicField.get->i am a publicField
12-26 23:57:11.785 17682-17682/myapplication.example.com.ndk_demo I/sakura: modified before privateStaticField.get->i am a privateStaticField
12-26 23:57:11.785 17682-17682/myapplication.example.com.ndk_demo I/sakura: modified after privateStaticField.get->modified
12-26 23:57:11.785 17682-17682/myapplication.example.com.ndk_demo I/sakura: testClazz3.getDeclaredFields->private java.lang.String myapplication.example.com.ndk_demo.Test.privateField
12-26 23:57:11.785 17682-17682/myapplication.example.com.ndk_demo I/sakura: testClazz3.getDeclaredFields->public java.lang.String myapplication.example.com.ndk_demo.Test.publicField
12-26 23:57:11.785 17682-17682/myapplication.example.com.ndk_demo I/sakura: testClazz3.getDeclaredFields->private static final java.lang.String myapplication.example.com.ndk_demo.Test.TAG
12-26 23:57:11.785 17682-17682/myapplication.example.com.ndk_demo I/sakura: testClazz3.getDeclaredFields->private static java.lang.String myapplication.example.com.ndk_demo.Test.privateStaticField
12-26 23:57:11.785 17682-17682/myapplication.example.com.ndk_demo I/sakura: testClazz3.getDeclaredFields->public static java.lang.String myapplication.example.com.ndk_demo.Test.publicStaticField
12-26 23:57:11.785 17682-17682/myapplication.example.com.ndk_demo I/sakura: testClazz3.getDeclaredMethod->public static void myapplication.example.com.ndk_demo.Test.publicStaticFunc()
12-26 23:57:11.785 17682-17682/myapplication.example.com.ndk_demo D/sakura_test: I`m from publicStaticFunc
12-26 23:57:11.786 17682-17682/myapplication.example.com.ndk_demo I/sakura: testClazz3.getDeclaredMethod->public void myapplication.example.com.ndk_demo.Test.publicFunc(java.lang.String)
12-26 23:57:11.786 17682-17682/myapplication.example.com.ndk_demo D/sakura_test: I`m from publicFunc sakura
memory list modules
Frida 反调试
这一节的主要内容就是关于反调试的原理和如何破解反调试，重要内容还是看文章理解即可。 因为我并不需要做反调试相关的工作，所以部分内容略过。
- Frida 反调试与反反调试基本思路
（Java 层 API、Native 层 API、Syscall)
Frida native hook : 符号 hook JNI、art&libc
Native 函数的 Java Hook 及主动调用
对 native 函数的 java 层 hook 和主动调用和普通 java 函数完全一致，略过。
jni.h头文件导入
导入 jni.h，先 search 一下这个文件在哪。
sakura@sakuradeMacBook-Pro:~/Library/Android/sdk$ find ./ -name "jni.h"
.//ndk-bundle/sysroot/usr/include/jni.h
Error /Users/sakura/Library/Android/sdk/ndk-bundle/sysroot/usr/include/jni.h,27: Can't open include file 'stdarg.h'
Total 1 errors
Caching 'Exports'... ok
报错，所以拷贝一份 jni.h 出来
将这两个头文件导入删掉
导入成功
现在就能识别_JNIEnv 了，如图
JNI 函数符号 hook
先查看一下导出了哪些函数。
extern "C" JNIEXPORT jstring JNICALL
Java_myapplication_example_com_ndk_1demo_MainActivity_stringFromJNI(
JNIEnv *env,
jobject /* this */) {
std::string hello = "Hello from C++";
LOGD("sakura1328");
return env->NewStringUTF(hello.c_str());
}
extern "C"
JNIEXPORT jstring JNICALL
Java_myapplication_example_com_ndk_1demo_MainActivity_stringWithJNI(JNIEnv *env, jobject instance,
jstring context_) {
const char *context = env->GetStringUTFChars(context_, 0);
int context_size = env->GetStringUTFLength(context_);
if (context_size > 0) {
LOGD("%s\n", context);
}
env->ReleaseStringUTFChars(context_, context);
return env->NewStringUTF("sakura1328");
}
这里有几个需要的 API。
- 首先是找到是否 so 被加载，通过
Process.enumerateModules(), 这个 API 可以枚举被加载到内存的 modules。 - 然后通过
Module.findBaseAddress(module name)来查找要 hook 的函数所在的 so 的基地址，如果找不到就返回 null。 - 然后可以通过
findExportByName(moduleName: string, exportName: string): NativePointer来查找导出函数的绝对地址。如果不知道 moduleName 是什么，可以传入一个 null 进入，但是会花费一些时间遍历所有的 module。如果找不到就返回 null。 - 找到地址之后，就可以拦截 function/instruction 的执行。通过
Interceptor.attach。使用方法见下代码。 - 另外为了将 jstring 的值打印出来，可以使用 jenv 的函数 getStringUtfChars，就像正常的写 native 程序一样。
Java.vm.getEnv().getStringUtfChars(args[2], null).readCString()
这里我是循环调用的 string_with_jni，如果不循环调用，那就要主动调用一下这个函数，或者 hook dlopen。 hook dlopen 的方法在这个代码可以参考。
function hook_native() {
// console.log(JSON.stringify(Process.enumerateModules()));
var libnative_addr = Module.findBaseAddress("libnative-lib.so")
console.log("libnative_addr is: " + libnative_addr)
if (libnative_addr) {
var string_with_jni_addr = Module.findExportByName("libnative-lib.so",
"Java_myapplication_example_com_ndk_1demo_MainActivity_stringWithJNI")
console.log("string_with_jni_addr is: " + string_with_jni_addr)
}
Interceptor.attach(string_with_jni_addr, {
onEnter: function (args) {
console.log("string_with_jni args: " + args[0], args[1], args[2])
console.log(Java.vm.getEnv().getStringUtfChars(args[2], null).readCString())
},
onLeave: function (retval) {
console.log("retval:", retval)
console.log(Java.vm.getEnv().getStringUtfChars(retval, null).readCString())
var newRetval = Java.vm.getEnv().newStringUtf("new retval from hook_native");
retval.replace(ptr(newRetval));
}
})
}
libnative_addr is: 0x7a0842f000
string_with_jni_addr is: 0x7a08436194
[Google Pixel::myapplication.example.com.ndk_demo]-> string_with_jni args: 0x7a106cc1c0 0x7ff0b71da4 0x7ff0b71da8
sakura
retval: 0x75
sakura1328
这里还写了一个 hook env 里的 GetStringUTFChars 的代码，和上面一样，不赘述了。
function hook_art(){
var addr_GetStringUTFChars = null;
//console.log( JSON.stringify(Process.enumerateModules()));
var symbols = Process.findModuleByName("libart.so").enumerateSymbols();
for(var i = 0;i<symbols.length;i++){
var symbol = symbols[i].name;
if((symbol.indexOf("CheckJNI")==-1)&&(symbol.indexOf("JNI")>=0)){
if(symbol.indexOf("GetStringUTFChars")>=0){
console.log(symbols[i].name);
console.log(symbols[i].address);
addr_GetStringUTFChars = symbols[i].address;
}
}
}
console.log("addr_GetStringUTFChars:", addr_GetStringUTFChars);
Java.perform(function (){
Interceptor.attach(addr_GetStringUTFChars, {
onEnter: function (args) {
console.log("addr_GetStringUTFChars OnEnter args[0],args[1]",args[0],args[1]);
//console.log(hexdump(args[0].readPointer()));
//console.log(Java.vm.tryGetEnv().getStringUtfChars(args[0]).readCString());
}, onLeave: function (retval) {
console.log("addr_GetStringUTFChars OnLeave",ptr(retval).readCString());
}
})
})
}
JNI 函数参数、返回值打印和替换
-
libc 函数符号 hook
-
libc 函数参数、返回值打印和替换
hook libc 的也和上面的完全一样，也不赘述了。 所以看到这里，究其本质就是找到导出符号和它所在的 so 基地址了。function hook_libc(){ var pthread_create_addr = null; var symbols = Process.findModuleByName("libc.so").enumerateSymbols(); for(var i = 0;i<symbols.length;i++){ var symbol = symbols[i].name; if(symbol.indexOf("pthread_create")>=0){ //console.log(symbols[i].name); //console.log(symbols[i].address); pthread_create_addr = symbols[i].address; } } console.log("pthread_create_addr,",pthread_create_addr); Interceptor.attach(pthread_create_addr,{ onEnter:function(args){ console.log("pthread_create_addr args[0],args[1],args[2],args[3]:",args[0],args[1],args[2],args[3]); },onLeave:function(retval){ console.log("retval is:",retval) } }) }
Frida native hook : JNI_Onload / 动态注册 / inline_hook/native 层调用栈打印
https://github.com/android/ndk-samples
JNI_Onload / 动态注册原理
- JNI_Onload / 动态注册 / Frida hook RegisterNative
详细的内容参见我写的文章，这里只给出栗子。
Log.d(TAG,stringFromJNI2());
public native String stringFromJNI2();
JNIEXPORT jstring JNICALL stringFromJNI2(
JNIEnv *env,
jclass clazz) {
jclass testClass = env->FindClass("myapplication/example/com/ndk_demo/Test");
jfieldID publicStaticField = env->GetStaticFieldID(testClass, "publicStaticField",
"Ljava/lang/String;");
jstring publicStaticFieldValue = (jstring) env->GetStaticObjectField(testClass,
publicStaticField);
const char *value_ptr = env->GetStringUTFChars(publicStaticFieldValue, NULL);
LOGD("now content is %s", value_ptr);
std::string hello = "Hello from C++ stringFromJNI2";
return env->NewStringUTF(hello.c_str());
}
...
JNIEXPORT jint JNI_OnLoad(JavaVM *vm, void *reserved) {
JNIEnv *env;
vm->GetEnv((void **) &env, JNI_VERSION_1_6);
JNINativeMethod methods[] = {
{"stringFromJNI2", "()Ljava/lang/String;", (void *) stringFromJNI2},
};
env->RegisterNatives(env->FindClass("myapplication/example/com/ndk_demo/MainActivity"), methods,
1);
return JNI_VERSION_1_6;
}
Frida hook RegisterNative
使用下面这个脚本来打印出 RegisterNatives 的参数，这里需要注意的是使用了 enumerateSymbolsSync, 它是 enumerateSymbols 的同步版本。
另外和我们之前通过Java.vm.tryGetEnv().getStringUtfChars来调用 env 里的方法不同。
这里则是通过将之前找到的 getStringUtfChars 函数地址和参数信息封装起来，直接调用，具体的原理我没有深入分析，先记住用法。
原理其实是一样的，都是根据符号找到地址，然后 hook 符号地址，然后打印参数。
declare const NativeFunction: NativeFunctionConstructor;
interface NativeFunctionConstructor {
new(address: NativePointerValue, retType: NativeType, argTypes: NativeType[], abiOrOptions?: NativeABI | NativeFunctionOptions): NativeFunction;
readonly prototype: NativeFunction;
}
...
var funcGetStringUTFChars = new NativeFunction(addrGetStringUTFChars, "pointer", ["pointer", "pointer", "pointer"]);
var ishook_libart = false;
function hook_libart() {
if (ishook_libart === true) {
return;
}
var symbols = Module.enumerateSymbolsSync("libart.so");
var addrGetStringUTFChars = null;
var addrNewStringUTF = null;
var addrFindClass = null;
var addrGetMethodID = null;
var addrGetStaticMethodID = null;
var addrGetFieldID = null;
var addrGetStaticFieldID = null;
var addrRegisterNatives = null;
var addrAllocObject = null;
var addrCallObjectMethod = null;
var addrGetObjectClass = null;
var addrReleaseStringUTFChars = null;
for (var i = 0; i < symbols.length; i++) {
var symbol = symbols[i];
if (symbol.name == "_ZN3art3JNI17GetStringUTFCharsEP7_JNIEnvP8_jstringPh") {
addrGetStringUTFChars = symbol.address;
console.log("GetStringUTFChars is at ", symbol.address, symbol.name);
} else if (symbol.name == "_ZN3art3JNI12NewStringUTFEP7_JNIEnvPKc") {
addrNewStringUTF = symbol.address;
console.log("NewStringUTF is at ", symbol.address, symbol.name);
} else if (symbol.name == "_ZN3art3JNI9FindClassEP7_JNIEnvPKc") {
addrFindClass = symbol.address;
console.log("FindClass is at ", symbol.address, symbol.name);
} else if (symbol.name == "_ZN3art3JNI11GetMethodIDEP7_JNIEnvP7_jclassPKcS6_") {
addrGetMethodID = symbol.address;
console.log("GetMethodID is at ", symbol.address, symbol.name);
} else if (symbol.name == "_ZN3art3JNI17GetStaticMethodIDEP7_JNIEnvP7_jclassPKcS6_") {
addrGetStaticMethodID = symbol.address;
console.log("GetStaticMethodID is at ", symbol.address, symbol.name);
} else if (symbol.name == "_ZN3art3JNI10GetFieldIDEP7_JNIEnvP7_jclassPKcS6_") {
addrGetFieldID = symbol.address;
console.log("GetFieldID is at ", symbol.address, symbol.name);
} else if (symbol.name == "_ZN3art3JNI16GetStaticFieldIDEP7_JNIEnvP7_jclassPKcS6_") {
addrGetStaticFieldID = symbol.address;
console.log("GetStaticFieldID is at ", symbol.address, symbol.name);
} else if (symbol.name == "_ZN3art3JNI15RegisterNativesEP7_JNIEnvP7_jclassPK15JNINativeMethodi") {
addrRegisterNatives = symbol.address;
console.log("RegisterNatives is at ", symbol.address, symbol.name);
} else if (symbol.name.indexOf("_ZN3art3JNI11AllocObjectEP7_JNIEnvP7_jclass") >= 0) {
addrAllocObject = symbol.address;
console.log("AllocObject is at ", symbol.address, symbol.name);
} else if (symbol.name.indexOf("_ZN3art3JNI16CallObjectMethodEP7_JNIEnvP8_jobjectP10_jmethodIDz") >= 0) {
addrCallObjectMethod = symbol.address;
console.log("CallObjectMethod is at ", symbol.address, symbol.name);
} else if (symbol.name.indexOf("_ZN3art3JNI14GetObjectClassEP7_JNIEnvP8_jobject") >= 0) {
addrGetObjectClass = symbol.address;
console.log("GetObjectClass is at ", symbol.address, symbol.name);
} else if (symbol.name.indexOf("_ZN3art3JNI21ReleaseStringUTFCharsEP7_JNIEnvP8_jstringPKc") >= 0) {
addrReleaseStringUTFChars = symbol.address;
console.log("ReleaseStringUTFChars is at ", symbol.address, symbol.name);
}
}
if (addrRegisterNatives != null) {
Interceptor.attach(addrRegisterNatives, {
onEnter: function (args) {
console.log("[RegisterNatives] method_count:", args[3]);
var env = args[0];
var java_class = args[1];
var funcAllocObject = new NativeFunction(addrAllocObject, "pointer", ["pointer", "pointer"]);
var funcGetMethodID = new NativeFunction(addrGetMethodID, "pointer", ["pointer", "pointer", "pointer", "pointer"]);
var funcCallObjectMethod = new NativeFunction(addrCallObjectMethod, "pointer", ["pointer", "pointer", "pointer"]);
var funcGetObjectClass = new NativeFunction(addrGetObjectClass, "pointer", ["pointer", "pointer"]);
var funcGetStringUTFChars = new NativeFunction(addrGetStringUTFChars, "pointer", ["pointer", "pointer", "pointer"]);
var funcReleaseStringUTFChars = new NativeFunction(addrReleaseStringUTFChars, "void", ["pointer", "pointer", "pointer"]);
var clz_obj = funcAllocObject(env, java_class);
var mid_getClass = funcGetMethodID(env, java_class, Memory.allocUtf8String("getClass"), Memory.allocUtf8String("()Ljava/lang/Class;"));
var clz_obj2 = funcCallObjectMethod(env, clz_obj, mid_getClass);
var cls = funcGetObjectClass(env, clz_obj2);
var mid_getName = funcGetMethodID(env, cls, Memory.allocUtf8String("getName"), Memory.allocUtf8String("()Ljava/lang/String;"));
var name_jstring = funcCallObjectMethod(env, clz_obj2, mid_getName);
var name_pchar = funcGetStringUTFChars(env, name_jstring, ptr(0));
var class_name = ptr(name_pchar).readCString();
funcReleaseStringUTFChars(env, name_jstring, name_pchar);
//console.log(class_name);
var methods_ptr = ptr(args[2]);
var method_count = parseInt(args[3]);
for (var i = 0; i < method_count; i++) {
var name_ptr = Memory.readPointer(methods_ptr.add(i * Process.pointerSize * 3));
var sig_ptr = Memory.readPointer(methods_ptr.add(i * Process.pointerSize * 3 + Process.pointerSize));
var fnPtr_ptr = Memory.readPointer(methods_ptr.add(i * Process.pointerSize * 3 + Process.pointerSize * 2));
var name = Memory.readCString(name_ptr);
var sig = Memory.readCString(sig_ptr);
var find_module = Process.findModuleByAddress(fnPtr_ptr);
console.log("[RegisterNatives] java_class:", class_name, "name:", name, "sig:", sig, "fnPtr:", fnPtr_ptr, "module_name:", find_module.name, "module_base:", find_module.base, "offset:", ptr(fnPtr_ptr).sub(find_module.base));
}
},
onLeave: function (retval) { }
});
}
ishook_libart = true;
}
hook_libart();
结果很明显的打印了出来，包括动态注册的函数的名字，函数签名，加载地址和在 so 里的偏移量，
[RegisterNatives] java_class: myapplication.example.com.ndk_demo.MainActivity name: stringFromJNI2 sig: ()Ljava/lang/String; fnPtr: 0x79f8698484 module_name: libnative-lib.so module_base: 0x79f8691000 offset: 0x7484
最后测试一下 yang 开源的一个 hook art 的脚本，很有意思，trace 出了非常多的需要的信息。
frida -U --no-pause -f package_name -l hook_art.js
...
[FindClass] name:myapplication/example/com/ndk_demo/Test
[GetStaticFieldID] name:publicStaticField, sig:Ljava/lang/String;
[GetStringUTFChars] result:i am a publicStaticField
[NewStringUTF] bytes:Hello from C++ stringFromJNI2
[GetStringUTFChars] result:sakura
native 层调用栈打印
直接使用 frida 提供的接口打印栈回溯。
Interceptor.attach(f, {
onEnter: function (args) {
console.log('RegisterNatives called from:\n' +
Thread.backtrace(this.context, Backtracer.ACCURATE)
.map(DebugSymbol.fromAddress).join('\n') + '\n');
}
});
效果如下, 我加到了 hook registerNative 的地方。
[Google Pixel::myapplication.example.com.ndk_demo]-> RegisterNatives called from:
0x7a100be03c libart.so!0xe103c
0x7a100be038 libart.so!0xe1038
0x79f85699a0 libnative-lib.so!_ZN7_JNIEnv15RegisterNativesEP7_jclassPK15JNINativeMethodi+0x44
0x79f85698e0 libnative-lib.so!JNI_OnLoad+0x90
0x7a102b9fd4 libart.so!_ZN3art9JavaVMExt17LoadNativeLibraryEP7_JNIEnvRKNSt3__112basic_stringIcNS3_11char_traitsIcEENS3_9allocatorIcEEEEP8_jobjectP8_jstringPS9_+0x638
0x7a08e3820c libopenjdkjvm.so!JVM_NativeLoad+0x110
0x70b921c4 boot.oat!oatexec+0xa81c4
主动调用去进行方法参数替换
使用Interceptor.replace，不赘述。主要目的还是为了改掉函数原本的执行行为，而不是仅仅打印一些信息。
inline hook
inline hook 简单理解就是不是 hook 函数开始执行的地方，而是 hook 函数中间执行的指令
整体来说没什么区别，就是把找函数符号地址改成从 so 里找到偏移，然后加到 so 基地址上就行, 注意一下它的 attach 的 callback。
/**
* Callback to invoke when an instruction is about to be executed.
*/
type InstructionProbeCallback = (this: InvocationContext, args: InvocationArguments) => void;
type InvocationContext = PortableInvocationContext | WindowsInvocationContext | UnixInvocationContext;
interface PortableInvocationContext {
/**
* Return address.
*/
returnAddress: NativePointer;
/**
* CPU registers. You may also update register values by assigning to these keys.
*/
context: CpuContext;
/**
* OS thread ID.
*/
threadId: ThreadId;
/**
* Call depth of relative to other invocations.
*/
depth: number;
/**
* User-defined invocation data. Useful if you want to read an argument in `onEnter` and act on it in `onLeave`.
*/
[x: string]: any;
}
...
...
interface Arm64CpuContext extends PortableCpuContext {
x0: NativePointer;
x1: NativePointer;
x2: NativePointer;
x3: NativePointer;
x4: NativePointer;
x5: NativePointer;
x6: NativePointer;
x7: NativePointer;
x8: NativePointer;
x9: NativePointer;
x10: NativePointer;
x11: NativePointer;
x12: NativePointer;
x13: NativePointer;
x14: NativePointer;
x15: NativePointer;
x16: NativePointer;
x17: NativePointer;
x18: NativePointer;
x19: NativePointer;
x20: NativePointer;
x21: NativePointer;
x22: NativePointer;
x23: NativePointer;
x24: NativePointer;
x25: NativePointer;
x26: NativePointer;
x27: NativePointer;
x28: NativePointer;
fp: NativePointer;
lr: NativePointer;
}
我的 so 是自己编译的，具体的汇编代码如下, 总之这里很明显在 775C 时，x0 里保存的是一个指向”sakura” 这个字符串的指针。(其实我也不是很看得懂 arm64 了已经，就随便 hook 了一下)
所以 hook 这个指令，然后Memory.readCString(this.context.x0);打印出来，结果如下
.text:000000000000772C ; __unwind {
.text:000000000000772C SUB SP, SP, #0x40
.text:0000000000007730 STP X29, X30, [SP,#0x30+var_s0]
.text:0000000000007734 ADD X29, SP, #0x30
.text:0000000000007738 ; 6: v6 = a1;
.text:0000000000007738 MOV X8, XZR
.text:000000000000773C STUR X0, [X29,#var_8]
.text:0000000000007740 ; 7: v5 = a3;
.text:0000000000007740 STUR X1, [X29,#var_10]
.text:0000000000007744 STR X2, [SP,#0x30+var_18]
.text:0000000000007748 ; 8: v4 = (const char *)_JNIEnv::GetStringUTFChars(a1, a3, 0LL);
.text:0000000000007748 LDUR X0, [X29,#var_8]
.text:000000000000774C LDR X1, [SP,#0x30+var_18]
.text:0000000000007750 MOV X2, X8
.text:0000000000007754 BL ._ZN7_JNIEnv17GetStringUTFCharsEP8_jstringPh ; _JNIEnv::GetStringUTFChars(_jstring *,uchar *)
.text:0000000000007758 STR X0, [SP,#0x30+var_20]
.text:000000000000775C ; 9: if ( (signed int)_JNIEnv::GetStringUTFLength(v6, v5) > 0 )
.text:000000000000775C LDUR X0, [X29,#var_8]
.text:0000000000007760 LDR X1, [SP,#0x30+var_18]
function inline_hook() {
var libnative_lib_addr = Module.findBaseAddress("libnative-lib.so");
if (libnative_lib_addr) {
console.log("libnative_lib_addr:", libnative_lib_addr);
var addr_775C = libnative_lib_addr.add(0x775C);
console.log("addr_775C:", addr_775C);
Java.perform(function () {
Interceptor.attach(addr_775C, {
onEnter: function (args) {
var name = this.context.x0.readCString()
console.log("addr_775C OnEnter :", this.returnAddress, name);
},
onLeave: function (retval) {
console.log("retval is :", retval)
}
})
})
}
}
setImmediate(inline_hook())
Attaching...
libnative_lib_addr: 0x79fabe0000
addr_775C: 0x79fabe775c
TypeError: cannot read property 'apply' of undefined
at [anon] (../../../frida-gum/bindings/gumjs/duktape.c:56618)
at frida/runtime/core.js:55
[Google Pixel::myapplication.example.com.ndk_demo]-> addr_775C OnEnter : 0x79fabe7758 sakura
addr_775C OnEnter : 0x79fabe7758 sakura
到这里已经可以总结一下我目前的学习了，需要补充一些 frida api 的学习，比如 NativePointr 里居然有个 readCString，这些 API 是需要再看看的。
Frida native hook : Frida hook native app 实战
- 破解 Frida 全端口检测的 native 层反调试
- hook libc 的 pthread_create 函数
- 破解 TracePid 的 native 反调试
- target: https://gtoad.github.io/2017/06/25/Android-Anti-Debug/
- solve : hook libc 的 fgets 函数
- native 层修改参数、返回值
- 静态分析
JNI_Onload - 动态 trace 主动注册 & IDA 溯源
- 动态 trace JNI、libc 函数 & IDA 溯源
- native 层主动调用、打调用栈
- 主动调用 libc 读写文件
看下 logcat
n/u0a128 for activity com.gdufs.xman/.MainActivity
12-28 05:53:26.898 26615 26615 V com.gdufs.xman: JNI_OnLoad()
12-28 05:53:26.898 26615 26615 V com.gdufs.xman: RegisterNatives() --> nativeMethod() ok
12-28 05:53:26.898 26615 26615 D com.gdufs.xman m=: 0
12-28 05:53:26.980 26615 26615 D com.gdufs.xman m=: Xman
sakura@sakuradeMacBook-Pro:~/gitsource/frida-agent-example/agent$ frida -U --no-pause -f com.gdufs.xman -l hook_reg.js
...
[Google Pixel::com.gdufs.xman]-> [RegisterNatives] method_count: 0x3
[RegisterNatives] java_class: com.gdufs.xman.MyApp name: initSN sig: ()V fnPtr: 0xd4ddf3b1 module_name: libmyjni.so module_base: 0xd4dde000 offset: 0x13b1
[RegisterNatives] java_class: com.gdufs.xman.MyApp name: saveSN sig: (Ljava/lang/String;)V fnPtr: 0xd4ddf1f9 module_name: libmyjni.so module_base: 0xd4dde000 offset: 0x11f9
[RegisterNatives] java_class: com.gdufs.xman.MyApp name: work sig: ()V fnPtr: 0xd4ddf4cd module_name: libmyjni.so module_base: 0xd4dde000 offset: 0x14cd
结合一下看，只要 initSN 检查到/sdcard/reg.dat里是EoPAoY62@ElRD，应该就会给 m 设置成 1。
只要 m 的值是 1，就能走到 work() 函数的逻辑。
function main() {
var file = new File("/sdcard/reg.dat",'w')
file.write("EoPAoY62@ElRD")
file.flush()
file.close()
}
setImmediate(main())
这样我们继续看 work 的逻辑
v2 是从 getValue 得到的，看上去就是 m 字段的值，此时应该是 1，一会 hook 一下看看。
[NewStringUTF] bytes:输入即是flag,格式为xman{……}！
callWork 里又调用了 work 函数，死循环了。
那看来看去最后还是回到了 initSN，那其实我们看的顺序似乎错了。 理一下逻辑，n2 执行完保存到文件，然后 n1 check 一下，所以最后还是要逆 n2 的算法，pass。
Frida trace 四件套
jni trace : trace jni
https://github.com/chame1eon/jnitrace
pip install jnitrace
Requirement already satisfied: frida>=12.5.0 in /Users/sakura/.pyenv/versions/3.7.7/lib/python3.7/site-packages (from jnitrace) (12.8.0)
Requirement already satisfied: colorama in /Users/sakura/.pyenv/versions/3.7.7/lib/python3.7/site-packages (from jnitrace) (0.4.3)
Collecting hexdump (from jnitrace)
Downloading https://files.pythonhosted.org/packages/55/b3/279b1d57fa3681725d0db8820405cdcb4e62a9239c205e4ceac4391c78e4/hexdump-3.3.zip
Installing collected packages: hexdump, jnitrace
Running setup.py install for hexdump ... done
Running setup.py install for jnitrace ... done
Successfully installed hexdump-3.3 jnitrace-3.0.8
usage: jnitrace [options] -l libname target
默认应该是 spawn 运行的，
-
-m来指定是spawn还是attach -
-b指定是fuzzy还是accurate -
-i <regex>指定一个正则表达式来过滤出方法名，例如-i Get -i RegisterNatives就会只打印出名字里包含 Get 或者 RegisterNatives 的 JNI methods。 -
-e <regex>和-i相反，同样通过正则表达式来过滤，但这次会将指定的内容忽略掉。 -
-I <string>trace 导出的方法，jnitrace 认为导出的函数应该是从 Java 端能够直接调用的函数，所以可以包括使用 RegisterNatives 来注册的函数，例如-I stringFromJNI -I nativeMethod([B)V，就包括导出名里有 stringFromJNI，以及使用 RegisterNames 来注册，并带有 nativeMethod([B)V 签名的函数。 -
-o path/output.json，导出输出到文件里。 -
-p path/to/script.js，用于在加载 jnitrace 脚本之前将指定路径的 Frida 脚本加载到目标进程中，这可以用于在 jnitrace 启动之前对抗反调试。 -
-a path/to/script.js，用于在加载 jnitrace 脚本之后将指定路径的 Frida 脚本加载到目标进程中 -
--ignore-env，不打印所有的 JNIEnv 函数 -
--ignore-vm，不打印所有的 JavaVM 函数sakura@sakuradeMacBook-Pro:~/Desktop/lab/alpha/tools/android/frida_learn/0620/0620/xman/resources/lib/armeabi-v7a$ jnitrace -l libmyjni.so com.gdufs.xman Tracing. Press any key to quit... Traced library "libmyjni.so" loaded from path "/data/app/com.gdufs.xman-X0HkzLhbptSc0tjGZ3yQ2g==/lib/arm". /* TID 28890 */ 355 ms [+] JavaVM->GetEnv 355 ms |- JavaVM* : 0xefe99140 355 ms |- void** : 0xda13e028 355 ms |: 0xeff312a0 355 ms |- jint : 65542 355 ms |= jint : 0 355 ms ------------------------Backtrace------------------------ 355 ms |-> 0xda13a51b: JNI_OnLoad+0x12 (libmyjni.so:0xda139000) /* TID 28890 */ 529 ms [+] JNIEnv->FindClass 529 ms |- JNIEnv* : 0xeff312a0 529 ms |- char* : 0xda13bdef 529 ms |: com/gdufs/xman/MyApp 529 ms |= jclass : 0x81 { com/gdufs/xman/MyApp } 529 ms ------------------------Backtrace------------------------ 529 ms |-> 0xda13a539: JNI_OnLoad+0x30 (libmyjni.so:0xda139000) /* TID 28890 */ 584 ms [+] JNIEnv->RegisterNatives 584 ms |- JNIEnv* : 0xeff312a0 584 ms |- jclass : 0x81 { com/gdufs/xman/MyApp } 584 ms |- JNINativeMethod* : 0xda13e004 584 ms |: 0xda13a3b1 - initSN()V 584 ms |: 0xda13a1f9 - saveSN(Ljava/lang/String;)V 584 ms |: 0xda13a4cd - work()V 584 ms |- jint : 3 584 ms |= jint : 0 584 ms ------------------------Backtrace------------------------ 584 ms |-> 0xda13a553: JNI_OnLoad+0x4a (libmyjni.so:0xda139000) /* TID 28890 */ 638 ms [+] JNIEnv->FindClass 638 ms |- JNIEnv* : 0xeff312a0 638 ms |- char* : 0xda13bdef 638 ms |: com/gdufs/xman/MyApp 638 ms |= jclass : 0x71 { com/gdufs/xman/MyApp } 638 ms -----------------------Backtrace----------------------- 638 ms |-> 0xda13a377: setValue+0x12 (libmyjni.so:0xda139000) /* TID 28890 */ 688 ms [+] JNIEnv->GetStaticFieldID 688 ms |- JNIEnv* : 0xeff312a0 688 ms |- jclass : 0x71 { com/gdufs/xman/MyApp } 688 ms |- char* : 0xda13be04 688 ms |: m 688 ms |- char* : 0xda13be06 688 ms |: I 688 ms |= jfieldID : 0xf1165004 { m:I } 688 ms -----------------------Backtrace----------------------- 688 ms |-> 0xda13a38d: setValue+0x28 (libmyjni.so:0xda139000)
strace : trace syscall
https://linuxtools-rst.readthedocs.io/zh_CN/latest/tool/strace.html
frida-trace : trace libc(or more)
https://frida.re/docs/frida-trace/
Usage:frida-trace [options] target
frida-trace -U -i "strcmp" -f com.gdufs.xman
...
5634 ms strcmp(s1="fi", s2="es-US")
5635 ms strcmp(s1="da", s2="es-US")
5635 ms strcmp(s1="es", s2="es-US")
5635 ms strcmp(s1="eu-ES", s2="es-US")
5635 ms strcmp(s1="et-EE", s2="es-US")
5635 ms strcmp(s1="et-EE", s2="es-US")
- art trace: hook artmethod
hook_artmethod : trace java 函数调用
https://github.com/lasting-yang/frida_hook_libart/blob/master/hook_artmethod.js
修改 AOSP 源码打印
Frida native hook : init_array 开发和自动化逆向
init_array 原理
常见的保护都会在 init_array 里面做，关于其原理，主要阅读以下文章即可。
IDA 静态分析 init_array
// 编译生成后在.init段 [名字不可更改]
extern "C" void _init(void) {
LOGD("Enter init......");
}
// 编译生成后在.init_array段 [名字可以更改]
__attribute__((__constructor__)) static void sakura_init() {
LOGD("Enter sakura_init......");
}
...
...
2016-12-29 16:51:23.017 5160-5160/com.example.ndk_demo D/sakura1328: Enter init......
2016-12-29 16:51:23.017 5160-5160/com.example.ndk_demo D/sakura1328: Enter sakura_init......
IDA 快捷键shift+F7找到 segment，然后就可以找到.init_array段，然后就可以找到里面保存的函数地址。
IDA 动态调试 so
-
打开要调试的 apk，找到入口
sakura@sakuradeMacBook-Pro:~/.gradle/caches$ adb shell dumpsys activity top | grep TASK TASK com.android.systemui id=29 userId=0 TASK null id=26 userId=0 TASK com.example.ndk_demo id=161 userId=0 -
启动 apk, 并让设备将处于一个 Waiting For Debugger 的状态
adb shell am start -D -n com.example.ndk_demo/.MainActivity -
执行 android_server64
sailfish:/data/local/tmp # ./android_server64 IDA Android 64-bit remote debug server(ST) v1.22. Hex-Rays (c) 2004-2017 Listening on 0.0.0.0:23946... -
新开一个窗口使用 forward 程序进行端口转发：
adb forward tcp:23946 tcp:23946
adb forward tcp:<本地机器的网络端口号> tcp:<模拟器或是真机的网络端口号>
例: adb [-d|-e|-s ] forward tcp:6100 tcp:7100 表示把本机的 6100 端口号与模拟器的 7100 端口建立起相关，当模拟器或真机向自己的 7100 端口发送了数据，那们我们可以在本机的 6100 端口读取其发送的内容，这是一个很关键的命令，以后我们使用 jdb 调试 apk 之前，就要用它先把目标进程和本地端口建立起关联
-
打开 IDA，选择菜单 Debugger -> Attach -> Remote ARM Linux/Android debugger
-
打开 IDA，选择菜单 Debugger -> Process options, 填好，然后选择进程去 attach。
-
查看待调试的进程
adb jdwpsakura@sakuradeMacBook-Pro:~$ adb jdwp 10436 -
转发端口
adb forward tcp:8700 jdwp:10436，将该进程的调试端口和本机的 8700 绑定。 -
jdb 连接调试端口，从而让程序继续运行
jdb -connect com.sun.jdi.SocketAttach:hostname=127.0.0.1,port=8700 -
找到断点并断下。
打开 module
找到 linker64
找到 call array 函数
下断并按 F9 断下
最终我确实可以调试到.init_array的初始化，具体的代码分析见 Linker 学习笔记这里。
init_array && JNI_Onload “自吐”
JNI_Onload
目标是找到动态注册的函数的地址，因为这种函数没有导出。
JNINativeMethod methods[] = {
{"stringFromJNI2", "()Ljava/lang/String;", (void *) stringFromJNI2},
};
env->RegisterNatives(env->FindClass("com/example/ndk_demo/MainActivity"), methods,
1);
首先jnitrace -m spawn -i "RegisterNatives" -l libnative-lib.so com.example.ndk_demo
525 ms [+] JNIEnv->RegisterNatives
525 ms |- JNIEnv* : 0x7a106cc1c0
525 ms |- jclass : 0x89 { com/example/ndk_demo/MainActivity }
525 ms |- JNINativeMethod* : 0x7ff0b71120
525 ms |: 0x79f00d36b0 - stringFromJNI2()Ljava/lang/String;
然后objection -d -g com.example.ndk_demo run memory list modules explore | grep demo
sakura@sakuradeMacBook-Pro:~$ objection -d -g com.example.ndk_demo run memory list modules explore | grep demo
[debug] Attempting to attach to process: `com.example.ndk_demo`
Warning: Output is not to a terminal (fd=1).
base.odex 0x79f0249000 106496 (104.0 KiB) /data/app/com.example.ndk_demo-HGAFhnKyKCSIpzn227pwXw==/oat/arm64/base.odex
libnative-lib.so 0x79f00c4000 221184 (216.0 KiB) /data/app/com.example.ndk_demo-HGAFhnKyKCSIpzn227pwXw==/lib/arm64/libnative...
offset = 0x79f00d36b0 - 0x79f00c4000 = 0xf6b0
这样就找到了
init_array
没有支持 arm64，可以在安装 app 的时候adb install --abi armeabi-v7a强制让 app 运行在 32 位模式
这个脚本整体来说就是 hook callfunction，然后打印出 init_array 里面的函数地址和参数等。
从源码看，关键就是 call_array 这里调用的 call_function，第一个参数代表这是注册的 init_array 里面的 function，第二个参数则是 init_array 里存储的函数的地址。
template <typename F>
static void call_array(const char* array_name __unused,
F* functions,
size_t count,
bool reverse,
const char* realpath) {
if (functions == nullptr) {
return;
}
TRACE("[ Calling %s (size %zd) @ %p for '%s' ]", array_name, count, functions, realpath);
int begin = reverse ? (count - 1) : 0;
int end = reverse ? -1 : count;
int step = reverse ? -1 : 1;
for (int i = begin; i != end; i += step) {
TRACE("[ %s[%d] == %p ]", array_name, i, functions[i]);
call_function("function", functions[i], realpath);
}
TRACE("[ Done calling %s for '%s' ]", array_name, realpath);
}
function LogPrint(log) {
var theDate = new Date();
var hour = theDate.getHours();
var minute = theDate.getMinutes();
var second = theDate.getSeconds();
var mSecond = theDate.getMilliseconds()
hour < 10 ? hour = "0" + hour : hour;
minute < 10 ? minute = "0" + minute : minute;
second < 10 ? second = "0" + second : second;
mSecond < 10 ? mSecond = "00" + mSecond : mSecond < 100 ? mSecond = "0" + mSecond : mSecond;
var time = hour + ":" + minute + ":" + second + ":" + mSecond;
var threadid = Process.getCurrentThreadId();
console.log("[" + time + "]" + "->threadid:" + threadid + "--" + log);
}
function hooklinker() {
var linkername = "linker";
var call_function_addr = null;
var arch = Process.arch;
LogPrint("Process run in:" + arch);
if (arch.endsWith("arm")) {
linkername = "linker";
} else {
linkername = "linker64";
LogPrint("arm64 is not supported yet!");
}
var symbols = Module.enumerateSymbolsSync(linkername);
for (var i = 0; i < symbols.length; i++) {
var symbol = symbols[i];
//LogPrint(linkername + "->" + symbol.name + "---" + symbol.address);
if (symbol.name.indexOf("__dl__ZL13call_functionPKcPFviPPcS2_ES0_") != -1) {
call_function_addr = symbol.address;
LogPrint("linker->" + symbol.name + "---" + symbol.address)
}
}
if (call_function_addr != null) {
var func_call_function = new NativeFunction(call_function_addr, 'void', ['pointer', 'pointer', 'pointer']);
Interceptor.replace(new NativeFunction(call_function_addr,
'void', ['pointer', 'pointer', 'pointer']), new NativeCallback(function (arg0, arg1, arg2) {
var functiontype = null;
var functionaddr = null;
var sopath = null;
if (arg0 != null) {
functiontype = Memory.readCString(arg0);
}
if (arg1 != null) {
functionaddr = arg1;
}
if (arg2 != null) {
sopath = Memory.readCString(arg2);
}
var modulebaseaddr = Module.findBaseAddress(sopath);
LogPrint("after load:" + sopath + "--start call_function,type:" + functiontype + "--addr:" + functionaddr + "---baseaddr:" + modulebaseaddr);
if (sopath.indexOf('libnative-lib.so') >= 0 && functiontype == "DT_INIT") {
LogPrint("after load:" + sopath + "--ignore call_function,type:" + functiontype + "--addr:" + functionaddr + "---baseaddr:" + modulebaseaddr);
} else {
func_call_function(arg0, arg1, arg2);
LogPrint("after load:" + sopath + "--end call_function,type:" + functiontype + "--addr:" + functionaddr + "---baseaddr:" + modulebaseaddr);
}
}, 'void', ['pointer', 'pointer', 'pointer']));
}
}
setImmediate(hooklinker)
我调试了一下 linker64，因为没有导出 call_function 的地址，所以不能直接 hook 符号名，而是要根据偏移去 hook，以后再说。
其实要看init_array，直接 shift+F7 去 segment 里面找.init_array段就可以了，这里主要是为了反反调试，因为可能反调试会加在 init_array 里，hook call_function 就可以让它不加载反调试程序。
native 层未导出函数主动调用（任意符号和地址）
现在我想要主动调用 sakura_add 来打印值, 可以 ida 打开找符号，或者根据偏移，总之最终用这个 NativePointer 指针来初始化一个 NativeFunction 来调用。
extern "C"
JNIEXPORT jint JNICALL
Java_com_example_ndk_1demo_MainActivity_sakuraWithInt(JNIEnv *env, jobject thiz, jint a, jint b) {
// TODO: implement sakuraWithInt()
return sakura_add(a,b);
}
...
int sakura_add(int a, int b){
int sum = a+b;
LOGD("sakura add a+b:",sum);
return sum;
}
function main() {
var libnative_lib_addr = Module.findBaseAddress("libnative-lib.so");
console.log("libnative_lib_addr is :", libnative_lib_addr);
if (libnative_lib_addr) {
var sakura_add_addr1 = Module.findExportByName("libnative-lib.so", "_Z10sakura_addii");
var sakura_add_addr2 = libnative_lib_addr.add(0x0F56C) ;
console.log("sakura_add_addr1 ", sakura_add_addr1);
console.log("sakura_add_addr2 ", sakura_add_addr2)
}
var sakura_add1 = new NativeFunction(sakura_add_addr1, "int", ["int", "int"]);
var sakura_add2 = new NativeFunction(sakura_add_addr2, "int", ["int", "int"]);
console.log("sakura_add1 result is :", sakura_add1(200, 33));
console.log("sakura_add2 result is :", sakura_add2(100, 133));
}
setImmediate(main())
...
...
libnative_lib_addr is : 0x79fa1c5000
sakura_add_addr1 0x79fa1d456c
sakura_add_addr2 0x79fa1d456c
sakura_add1 result is : 233
sakura_add2 result is : 233
C/C++ hook
//todo
Native/JNI 层参数打印和主动调用参数构造
jni 的基本类型要通过调用 jni 相关的 api 转化成 c++ 对象，才能打印和调用。
jni 主动调用的时候，参数构造有两种方式，一种是Java.vm.getenv，另一种是 hook 获取 env 之后来调用 jni 相关的 api 构造参数。
C/C++ 编成 so 并引入 Frida 调用其中的函数
致谢
本篇文章学到的内容来自且完全来自 r0ysue 的知识星球，推荐一下。
