Frida Tutorial 2

Reading time: 5 minutes

Hii ni muhtasari wa chapisho: https://11x256.github.io/Frida-hooking-android-part-2/ (Sehemu 2, 3 & 4)
APKs na Msimbo wa Chanzo: https://github.com/11x256/frida-android-examples

Sehemu ya 1 ni rahisi sana.

Sehemu zingine za msimbo wa asili hazifanyi kazi na zimebadilishwa hapa.

Sehemu ya 2

Hapa unaweza kuona mfano wa jinsi ya kuhook kazi 2 zenye jina moja lakini parameta tofauti.
Pia, utaweza kujifunza jinsi ya kuita kazi kwa parameta zako mwenyewe.
Na hatimaye, kuna mfano wa jinsi ya kupata mfano wa darasa na kufanya liite kazi.

//s2.js
console.log("Script loaded successfully ");
Java.perform(function x() {
console.log("Inside java perform function");
var my_class = Java.use("com.example.a11x256.frida_test.my_activity");
//Hook "fun" with parameters (int, int)
my_class.fun.overload("int", "int").implementation = function (x, y) { //hooking the old function
console.log("original call: fun(" + x + ", " + y + ")");
var ret_value = this.fun(2, 5);
return ret_value;
};
//Hook "fun" with paramater(String)
var string_class = Java.use("java.lang.String");
my_class.fun.overload("java.lang.String").implementation = function (x) { //hooking the new function
console.log("*")
//Create a new String and call the function with your input.
var my_string = string_class.$new("My TeSt String#####");
console.log("Original arg: " + x);
var ret = this.fun(my_string);
console.log("Return value: " + ret);
console.log("*")
return ret;
};
//Find an instance of the class and call "secret" function.
Java.choose("com.example.a11x256.frida_test.my_activity", {
onMatch: function (instance) {
console.log(tring, and the it has"Found instance: " + instance);
console.log("Result of secret func: " + instance.secret());
},
onComplete: function () { }
});
});

Unaweza kuona kwamba ili kuunda String kwanza imeelekeza kwenye darasa java.lang.String na kisha imeunda kitu $new cha darasa hilo chenye String kama maudhui. Hii ndiyo njia sahihi ya kuunda kitu kipya cha darasa. Lakini, katika kesi hii, unaweza tu kupitisha this.fun() String yoyote kama: this.fun("hey there!")

Python

//loader.py
import frida
import time

device = frida.get_usb_device()
pid = device.spawn(["com.example.a11x256.frida_test"])
device.resume(pid)
time.sleep(1) #Without it Java.perform silently fails
session = device.attach(pid)
script = session.create_script(open("s2.js").read())
script.load()

#prevent the python script from terminating
raw_input()

python loader.py

Sehemu ya 3

Python

Sasa utaona jinsi ya kutuma amri kwa programu iliyounganishwa kupitia Python ili kuita kazi:

//loader.py
import time
import frida

def my_message_handler(message, payload):
print message
print payload


device = frida.get_usb_device()
pid = device.spawn(["com.example.a11x256.frida_test"])
device.resume(pid)
time.sleep(1)  # Without it Java.perform silently fails
session = device.attach(pid)
with open("s3.js") as f:
script = session.create_script(f.read())
script.on("message", my_message_handler)
script.load()

command = ""
while 1 == 1:
command = raw_input("Enter command:\n1: Exit\n2: Call secret function\n3: Hook Secret\nchoice:")
if command == "1":
break
elif command == "2":
script.exports.callsecretfunction()
elif command == "3":
script.exports.hooksecretfunction()

Amri "1" itatoa, amri "2" itapata na mfano wa darasa na kuita kazi ya faragha secret() na amri "3" itachomeka kazi secret() ili irejeshe nyuzi tofauti.

Hivyo, ukitaja "2" utapata siri halisi, lakini ukitaja "3" kisha "2" utapata siri bandia.

JS

console.log("Script loaded successfully ")
var instances_array = []
function callSecretFun() {
Java.perform(function () {
if (instances_array.length == 0) {
// if array is empty
Java.choose("com.example.a11x256.frida_test.my_activity", {
onMatch: function (instance) {
console.log("Found instance: " + instance)
instances_array.push(instance)
console.log("Result of secret func: " + instance.secret())
},
onComplete: function () {},
})
} else {
//else if the array has some values
console.log("Result of secret func: " + instances_array[0].secret())
}
})
}

function hookSecret() {
Java.perform(function () {
var my_class = Java.use("com.example.a11x256.frida_test.my_activity")
var string_class = Java.use("java.lang.String")
my_class.secret.overload().implementation = function () {
var my_string = string_class.$new("TE ENGANNNNEEE")
return my_string
}
})
}
rpc.exports = {
callsecretfunction: callSecretFun,
hooksecretfunction: hookSecret,
}

Sehemu ya 4

Hapa utaona jinsi ya kufanya Python na JS kuingiliana kwa kutumia vitu vya JSON. JS inatumia kazi ya send() kutuma data kwa mteja wa python, na Python inatumia kazi za post() kutuma data kwa skripti ya JS. JS itazuia utekelezaji hadi ipokee jibu kutoka kwa Python.

Python

//loader.py
import time
import frida

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")
user, pw = data.split(":")
data = ("admin" + ":" + pw).encode("base64")
print "encoded data:", data
script.post({"my_data": data})  # send JSON object
print "Modified data sent"


device = frida.get_usb_device()
pid = device.spawn(["com.example.a11x256.frida_test"])
device.resume(pid)
time.sleep(1)
session = device.attach(pid)
with open("s4.js") as f:
script = session.create_script(f.read())
script.on("message", my_message_handler)  # register the message handler
script.load()
raw_input()

JS

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
}).wait() //block execution till the message is received
console.log("Final string_to_recv: " + string_to_recv)
return this.setText(string_to_recv)
}
})

Kuna sehemu ya 5 ambayo sitafafanua kwa sababu hakuna kitu kipya. Lakini ikiwa unataka kusoma, iko hapa: https://11x256.github.io/Frida-hooking-android-part-5/