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()
