Android PentesterLab06 - Reverse Engineering apk application | Shahul Hameed


How to reverse engineering in Android application

    Required tools : 

        1. JAD ()

        2. DEX2JAR ()

        3. 7ZIP

    Note: Put your apk app and all tools in a single folder(to easy access).

Step 1:  To redirect the command prompt directly.


Step 2: Convert DEX to JAR

 Using tool dex2jar


    Now we got extracted file



Step 3: We extracted the jar file 

    Using the 7Zip tool 


Choose your required files and copy them to your local disk.


Now we got Class files but we can’t edit them so next, we have to convert the Class file into Java.

    Using a tool: JAD

Step 4:

    Convert class file to java file




Use any online java compiler to execute the below code.

    Note: Take the secret key from a.java and MessageActivity.java source code.

import java.util.Base64;

import javax.crypto.Cipher;

import javax.crypto.spec.IvParameterSpec;

import javax.crypto.spec.SecretKeySpec;

public class Main

{

    public static void main(String[] args) {

        try

        {

            String s ="ygiG2VpgnW6z2ocCPEVaYhDwBs3UxZENbgh1iQJ6NhpBqHsczQsDh1rD3WjejQ7JH1o+lvBdtxhG64qyLQyHSg";

            String key = "__pentesterlab__";

            byte abyte1[] = Base64.getDecoder().decode(s);

            byte iv[] = new byte[16];

            System.arraycopy(abyte1, 0, iv, 0, 16);

            IvParameterSpec ivparameterspec = new IvParameterSpec(iv);

            int z = abyte1.length - 16;

            byte enc[] = new byte[z];

            System.arraycopy(abyte1, 16, enc, 0, z);

            SecretKeySpec skey = new SecretKeySpec(key.getBytes(), "AES");

            Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");

            cipher.init(2,skey, ivparameterspec);

            String res = new String(cipher.doFinal(enc));

            System.out.println(res);

        }

        // Misplaced declaration of an exception variable

        catch(Exception e)

        {

            e.printStackTrace();

        }

    }

}




Step 5: Finally, we got the key.


Comments

Post a Comment

Popular posts from this blog

Using Burp Suite - Brute Force payloads using XSS Validator(Extension) | Shahul Hameed

Image
XSS Brute Force Payloads using Burp Suite  Step 1: Get the parameter variable from the scope URL. Step 2: Intercept the parameter value using the burp suite application as shown in the below screenshot. Step 3: Clear and add the variable position which goes to perform an attack on the brute force of XSS payloads. Step 4: Install xssValidator extension in the burp suite and we can also add custom payloads in the below payloads box. Step 5: Set the following options in the Payloads option. Step 6: In Intruder clear, the Grep-Match and Grep-Payloads checked option search responses for payload strings. Step 7: Copy the grep phase from xssValidator and paste it into the intruder grep-match. Step 8: Unchecked the option from the payload encoding. Step 9: Start the attack and check the results with the grep value is 1 manually in the web browser which exploited the XSS attack payload.
Read more

Janus Vulnerability Exploitation

Image
  Janus Vulnerability(Exploitation) In brief, Applications that are signed only with v1 when installed on devices having an android version(5.0–8.0) are vulnerable to Janus Vulnerability. Step 1: Use the  apksigner tool and verify the signature v1 is only true , Hence it's highly possible to exploit the Janus vulnerability in the android application. CMD: apksigner verify -verbose h5.apk(Victim app) Before that we need to make sure that this application can be made to run on vulnerable Android versions  5.x, 6.x, 7.x & 8.0 (i.e., api level 21–26). Step 2:  Now let's check with min android version running on the application use apktool . CMD: apktool -s d H5.apk && cat H5/apktool.yml | grep minSdk The below application can be run on API Level 15(Android 4.0.4 Ice Cream Sandwich), so we can choose any device from  5.x, 6.x, 7.x & 8.0  to exploit it. A serious vulnerability in Android allows attackers to inject a DEX file into an APK file without affecting the sig
Read more

SQL Basics | Shahul Hameed

Image
  SQL _Queries   Resource: https://balanced-quince-db1.notion.site/SQL-7347f5956fe347f887b4132c716cd236#17bc403a1add453db519621da47c1de3 Database queries CREATE DATABASE LOGICFIRST; -- creates a new database -- TO DELETE A DATABASE DROP DATABASE LOGICFIRST; DROP SCHEMA LOGICFIRST; -- same as above. u can use DATABASE Or SCHEMA DROP SCHEMA IF EXISTS LOGICFIRST; -- prevents error if db not found   SHOW DATABASES; -- shows all the databases SHOW SCHEMAS; -- same as above. shows schemas/db   USE SYS; -- uses this database for all further commands SHOW TABLES;-- shows all tables in the database being used Table - Create,Delete,Alter primary key - uniquely identifies a row in a table //creating a table CREATE TABLE student(                id INT PRIMARY KEY,     name VARCHAR(30),     gpa DECIMAL(3,2) ); -- ----or----- CREATE TABLE student(                id INT,     name VARCHAR(30),     gpa DECIMAL(3,2),     PRIMARY KEY(id) );  
Read more