Frida tutorijal

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Instalacija

Instalirajte frida tools:

bash
pip install frida-tools
pip install frida

Preuzmite i instalirajte na Androidu frida server (Download the latest release).
Jednolinijska naredba za restart adb-a u root režimu, povezivanje na uređaj, upload frida-server, dodeljivanje exec dozvola i pokretanje u pozadini:

bash
adb root; adb connect localhost:6000; sleep 1; adb push frida-server /data/local/tmp/; adb shell "chmod 755 /data/local/tmp/frida-server"; adb shell "/data/local/tmp/frida-server &"

Proverite da li radi:

bash
frida-ps -U #List packages and processes
frida-ps -U | grep -i <part_of_the_package_name> #Get all the package name

Frida server vs. Gadget (root vs. no-root)

Dva uobičajena načina za instrumentovanje Android aplikacija pomoću Frida:

  • Frida server (rooted devices): Prebacite i pokrenite native daemon koji vam omogućava da se povežete sa bilo kojim procesom.
  • Frida Gadget (no root): Ugradite Frida kao shared library unutar APK-a i automatski je učitajte u ciljnom procesu.

Frida server (rooted)

bash
# Download the matching frida-server binary for your device's arch
# https://github.com/frida/frida/releases
adb root
adb push frida-server-<ver>-android-<arch> /data/local/tmp/frida-server
adb shell chmod 755 /data/local/tmp/frida-server
adb shell /data/local/tmp/frida-server &    # run at boot via init/magisk if desired

# From host, list processes and attach
frida-ps -Uai
frida -U -n com.example.app

Frida Gadget (no-root)

  1. Raspakujte APK, dodajte gadget .so i konfiguraciju:
  • Postavite libfrida-gadget.so u lib// (npr. lib/arm64-v8a/)
  • Kreirajte assets/frida-gadget.config sa podešavanjima za učitavanje skripte

Primer frida-gadget.config

json
{
"interaction": { "type": "script", "path": "/sdcard/ssl-bypass.js" },
"runtime": { "logFile": "/sdcard/frida-gadget.log" }
}
  1. Referencirajte/učitajte gadget tako da bude inicijalizovan rano:
  • Najlakše: Dodajte mali Java stub koji poziva System.loadLibrary("frida-gadget") u Application.onCreate(), ili koristite native lib loading koji je već prisutan.
  1. Ponovo upakujte i potpišite APK, zatim instalirajte:
bash
apktool d app.apk -o app_m
# ... add gadget .so and config ...
apktool b app_m -o app_gadget.apk
uber-apk-signer -a app_gadget.apk -o out_signed
adb install -r out_signed/app_gadget-aligned-debugSigned.apk
  1. Attach sa hosta na gadget process:
bash
frida-ps -Uai
frida -U -n com.example.app

Napomene

  • Gadget je detektovan od strane nekih zaštita; držite imena/putanje prikrivenim i učitavajte kasno/uslovno po potrebi.
  • Kod ojačanih aplikacija, preferirajte testiranje na rootovanom uređaju sa serverom + kasnim attach-ovanjem, ili kombinujte sa sakrivanjem pomoću Magisk/Zygisk.

Vodiči

Tutorial 1

Izvor: https://medium.com/infosec-adventures/introduction-to-frida-5a3f51595ca1
APK: https://github.com/t0thkr1s/frida-demo/releases
Izvorni kod: https://github.com/t0thkr1s/frida-demo

Pratite link to read it.

Tutorial 2

Izvor: https://11x256.github.io/Frida-hooking-android-part-2/ (Parts 2, 3 & 4)
APKs i Izvorni kod: https://github.com/11x256/frida-android-examples

Pratite link to read it.

Tutorial 3

Izvor: https://joshspicer.com/android-frida-1
APK: https://github.com/OWASP/owasp-mstg/blob/master/Crackmes/Android/Level_01/UnCrackable-Level1.apk

Pratite link to read it.

Vi možete pronaći više Awesome Frida skripti ovde: https://codeshare.frida.re/

Brzi primeri

Pozivanje Frida iz komandne linije

bash
frida-ps -U

#Basic frida hooking
frida -l disableRoot.js -f owasp.mstg.uncrackable1

#Hooking before starting the app
frida -U --no-pause -l disableRoot.js -f owasp.mstg.uncrackable1
#The --no-pause and -f options allow the app to be spawned automatically,
#frozen so that the instrumentation can occur, and the automatically
#continue execution with our modified code.

Osnovna Python skripta

python
import frida, sys

jscode = open(sys.argv[0]).read()
process = frida.get_usb_device().attach('infosecadventures.fridademo')
script = process.create_script(jscode)
print('[ * ] Running Frida Demo application')
script.load()
sys.stdin.read()

Hooking funkcija bez parametara

Hook funkciju a() klase sg.vantagepoint.a.c

javascript
Java.perform(function () {
;  rootcheck1.a.overload().implementation = function() {
rootcheck1.a.overload().implementation = function() {
send("sg.vantagepoint.a.c.a()Z   Root check 1 HIT!  su.exists()");
return false;
};
});

Hook java exit()

javascript
var sysexit = Java.use("java.lang.System")
sysexit.exit.overload("int").implementation = function (var_0) {
send("java.lang.System.exit(I)V  // We avoid exiting the application  :)")
}

Hook MainActivity .onStart() i .onCreate()

javascript
var mainactivity = Java.use("sg.vantagepoint.uncrackable1.MainActivity")
mainactivity.onStart.overload().implementation = function () {
send("MainActivity.onStart() HIT!!!")
var ret = this.onStart.overload().call(this)
}
mainactivity.onCreate.overload("android.os.Bundle").implementation = function (
var_0
) {
send("MainActivity.onCreate() HIT!!!")
var ret = this.onCreate.overload("android.os.Bundle").call(this, var_0)
}

Hook android .onCreate()

javascript
var activity = Java.use("android.app.Activity")
activity.onCreate.overload("android.os.Bundle").implementation = function (
var_0
) {
send("Activity HIT!!!")
var ret = this.onCreate.overload("android.os.Bundle").call(this, var_0)
}

Hooking funkcija sa parametrima i dohvatanje vrednosti

Hooking a decryption function. Ispisati input, pozvati originalnu funkciju za decryption inputa i na kraju ispisati nešifrovane podatke:

javascript
function getString(data) {
var ret = ""
for (var i = 0; i < data.length; i++) {
ret += data[i].toString()
}
return ret
}
var aes_decrypt = Java.use("sg.vantagepoint.a.a")
aes_decrypt.a.overload("[B", "[B").implementation = function (var_0, var_1) {
send("sg.vantagepoint.a.a.a([B[B)[B   doFinal(enc)  // AES/ECB/PKCS7Padding")
send("Key       : " + getString(var_0))
send("Encrypted : " + getString(var_1))
var ret = this.a.overload("[B", "[B").call(this, var_0, var_1)
send("Decrypted : " + ret)

var flag = ""
for (var i = 0; i < ret.length; i++) {
flag += String.fromCharCode(ret[i])
}
send("Decrypted flag: " + flag)
return ret //[B
}

Hooking funkcija i pozivanje istih sa našim ulazom

Hook funkciju koja prima string i pozovi je drugim stringom (from here)

javascript
var string_class = Java.use("java.lang.String") // get a JS wrapper for java's String class

my_class.fun.overload("java.lang.String").implementation = function (x) {
//hooking the new function
var my_string = string_class.$new("My TeSt String#####") //creating a new String by using `new` operator
console.log("Original arg: " + x)
var ret = this.fun(my_string) // calling the original function with the new String, and putting its return value in ret variable
console.log("Return value: " + ret)
return ret
}

Dobijanje već kreiranog objekta klase

Ako želite da izdvojite neki atribut iz već kreiranog objekta, možete koristiti ovo.

U ovom primeru ćete videti kako da dobijete objekat klase my_activity i kako da pozovete funkciju .secret() koja će ispisati privatni atribut objekta:

javascript
Java.choose("com.example.a11x256.frida_test.my_activity", {
onMatch: function (instance) {
//This function will be called for every instance found by frida
console.log("Found instance: " + instance)
console.log("Result of secret func: " + instance.secret())
},
onComplete: function () {},
})

Ostali Frida tutorijali

Reference

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Učite i vežbajte GCP Hacking: HackTricks Training GCP Red Team Expert (GRTE) Učite i vežbajte Azure Hacking: HackTricks Training Azure Red Team Expert (AzRTE)

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