SMS Trojans: all around the world

How SMS trojans works and how it affect our smart phones. Lets take a look.

I like researching and get knowledge about technology. Good and Bad parts of it and I found a strange thing about Android Device's Malware.

I found a good article about an SMS trojan at SecureList.com

There is an Application named "SuiConFo". Actually its a good application but someone has created the bogus app with same name which is popular in market. It looks like after installing.



There are 2 main malicious classes of this Trojan: ‘MagicSMSActivity.class' and ‘SMSReceiver.class'. The first is mainly responsible for sending SMS messages, while the second is used to hide incoming messages from specific numbers. As mentioned above, after launching this app shows an ‘Android version is not compatible' error message:



Right after displaying this message the Trojan will call the public method getSimCountryIso in theTelephonyManager class in order to retrieve the ISO country code of the SIM card:



After that, the malware defines the variables ‘s1' (SMS number) and ‘s2' (SMS text):



The list of countries consists of 8 options: France (81001 SMS number), Belgium (9903 SMS number), Switzerland (543 SMS number), Luxembourg (64747 SMS number), Canada (60999 SMS number), Germany (63000 SMS number), Spain (35064 SMS number), and the UK (60999 SMS number).
It looks like the virus writers made a mistake in the code. The Trojan will send an SMS message using the SmsManager class with the sendTextMessage method:
smsmanager.sendTextMessage(s1, null, s2, pendingintent, pendingintent1)
where ‘s1' is a number and ‘s2' is a text. These variables are defined correctly for all countries except Canada:

if(s.equals("ca"))
{
s1 = "SP";
s2 = "60999";

After defining the country and, therefore, the number and message text, the Trojan will send 4 SMS messages with the help of the sendTextMessage method as mentioned above.

SMSReceiver.class is responsible for hiding incoming SMS messages from particular numbers. If there is an incoming SMS message from one of the following numbers: 81001, 35064, 63000, 9903, 60999, 543, 64747, then the Trojan will try to hide it using the abortBroadcast method. The number itself is retrieved from the SMS message with the help of getDisplayOriginatingAddress.

There is another interesting thing lurking inside this malware. If you look at this part of the code:

you may notice that after hiding the incoming message (abortBroadcast) this Trojan will send one more SMS to a French cell phone number with the text stored in the ‘s' variable. And that ‘s' variable is defined with the help of the getMessageBody method when an incoming SMS message arrives.

In other words, the Trojan will send an SMS message to a French cell phone number with the text taken from a reply from a premium rate number. This may help the cybercriminals find out how many premium SMS messages have been sent.

Unfortunately, today SMS Trojans are one the easiest ways for cybercriminals to make easy money fast. 

Only advise is do not to install any application just for try. Install only popular application from "Google Play Market" only. Do not install application directly i.e "APK" files. 

Display Alert on Back button Pressed in Android Studio

Display Alert on Back button Pressed in Android Studio

Description: When user wants to exit from application, he is prompted to exit from application.

Complexity Level: Beginner

Keywords: back, back button, android, android studio, alert, dialog, onbackpress

                Alert means to get user’s input when needed. Most of us played games and when we try to exit it by pressing “Back” button in Android phone, it ask for “Do you really want to exit?”.             So, in this article we are going to learn how to prevent user to exit from application without giving response. 

Step 1:

Create a new Project with following parameters.

Step 2:

Open your Main Activity file, in my case it is “BackPressActivity” and paste following code inside.

===============

BackPressActivity

===============

package com.example.alertonbackpressdemo;

import android.app.AlertDialog;

import android.content.DialogInterface;

import android.os.Bundle;

import android.app.Activity;

import android.view.Menu;

public class BackPressActivity extends Activity {

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

    }

    @Override

    public void onBackPressed() {

        AlertDialog.Builder builder = new AlertDialog.Builder(this);

        builder.setCancelable(false);

        builder.setMessage("Do you want to Exit?");

        builder.setPositiveButton("Yes", new DialogInterface.OnClickListener() {

            @Override

            public void onClick(DialogInterface dialog, int which) {

                //if user pressed "yes", then he is allowed to exit from application

                finish();

            }

        });

        builder.setNegativeButton("No",new DialogInterface.OnClickListener() {

            @Override

            public void onClick(DialogInterface dialog, int which) {

                //if user select "No", just cancel this dialog and continue with app

                dialog.cancel();

            }

        });

        AlertDialog alert=builder.create();

        alert.show();

    }   

}

Let’s understand Alert Dialog and its different methods.

In code there is written “builder.setCancelable(false);” which means that user can’t cancel this dialog by pressing back again or touch outside the alert dialog box and dismiss it. So user has to press one of the options you have provided to him.

Next is “builder.setMessage("Do you want to Exit?");”. Here you can write your own message which will be displayed to user in alert.

“builder.setPositiveButton” will set a positive button in left side. Parameter will accept the name of that button as you can see in code is “Yes”. Same thing is set for “builder.setNegativeButton”. When you set these buttons, you need to pass a listener which will be fired when user click one of the button.

Step 3:

Run your application.

Summary

 In this article, we learned “How to show Alert Dialog” and “Show dialog at BACK button pressed”.