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Class 0 SMS (flash SMS) on Android

Tags:

android

sms

gsm

As I know that Nokia and some others phone (like iPhone) are able to sent and receive class 0 SMS , is it possible for android ? Do Android have the API?

What is flash SMS?

Flash SMS is an SMS which is displayed on the phone screen immediately upon arrival.

Unless you choose to save the flash message, it will disappear upon navigating away and will not be saved in your inbox.

If several flash messages are sent to one phone, only the latest message will be displayed, and all the previous ones will be overwritten.

Class 0: Indicates that this message is to be displayed on the MS immediately and a message delivery report is to be sent back to the SC. The message does not have to be saved in the MS or on the SIM card (unless selected to do so by the mobile user).

like image 442
xDragonZ Avatar asked Feb 03 '12 03:02

xDragonZ


People also ask

What is flash SMS or Class 0 SMS?

Class 0 SMS, or Flash SMS, is a type of message defined in the GSM specification that gets displayed directly on the phone's screen and doesn't automatically get stored on the device. After reading such a message, users have the option to save it or dismiss it.

Why do I get Class 0 messages?

Whenever a Class 0 message appears, it thinks of a new message and the app is turned on, which let the Gpay or other apps think the User has switched app. Solution: Download another messaging app from Play Store (sms organizer from Microsoft, Pulse Sms...,etc) and make it the default.

Why did I get a flash SMS?

This is a reaction of the manufacturers to phishing via SMS. Since Flash SMS messages look like a system message on many devices, this is supposed to prevent consumers from falling for scammers who misuse the sender ID to disguise their message as an official message.


2 Answers

For rooted Android it is possible to bypass an API and send Class 0 SMS. There is a project on Git Hub called ZeroSMS:

ZeroSMS is a proof-of-concept demonstrating a way to send Class 0 SMS on android >=2.3.

Note: this only works on versions 2.2 -> 4.1.2, the sendRawPdu method was removed, so you will need to find a new way to do this.

like image 154
Scrool Avatar answered Sep 18 '22 15:09

Scrool


It was possible to send Flash SMS (that's the term for class 0 SMS) before Android 2.2. Google removed the sendRawPdu API, so even if you used reflection, you wouldn't be able to do it.

Here's how I did it previously (this was tested on Android 1.6 and worked)

private void sendSms(String phone, String sms) {
    if ((phone == null) || (sms == null) || (phone.length() == 0)
            || (sms.length() == 0)) {
        String message = "Phone or message empty!!!";
        Toast notification = Toast.makeText(getBaseContext(), message,
                Toast.LENGTH_SHORT);
        notification.show();
        return;
    }

    // SecurityManager oldSM = System.getSecurityManager();
    // MySecurityManager newSM = new MySecurityManager();
    // System.setSecurityManager(newSM);

    // ServiceManager.getService("isms")
    // ServiceManager.getService("isms");

    SmsManager m = SmsManager.getDefault();
    PendingIntent sentIntent = PendingIntent
            .getBroadcast(this, 0, new Intent(
                    MessageStatusReceiver_MESSAGE_STATUS_RECEIVED_ACTION),
                    0);

    PendingIntent deliveryIntent = PendingIntent.getBroadcast(this, 0,
            new Intent(SmsReceiverService_MESSAGE_SENT_ACTION), 0);

    // String sms = "Message self-destroyed!!!";
    // String phone = "93634096";

    long NOW = System.currentTimeMillis();
    String time = String.valueOf(NOW);

    // // m.sendTextMessage(phone, null, sms, sentIntent, deliveryIntent);
    // working // m.sendTextMessage(phone, null, sms, null, null);
    byte[] bb = new byte[1];
    Method m2 = null;
    try {
        m2 = SmsManager.class.getDeclaredMethod("sendRawPdu",
                bb.getClass(), bb.getClass(), PendingIntent.class,
                PendingIntent.class);
    } catch (SecurityException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (NoSuchMethodException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

    // send message

    SmsMessage.SubmitPdu pdus = SmsMessage.getSubmitPdu(null, phone, sms,
            false);

    // http://android.git.kernel.org/?p=platform/frameworks/base.git;a=blob;f=telephony/java/android/telephony/gsm/SmsMessage.java;h=9ccfa90d2e24e5caea26c1deac641b3c31ae56d4;hb=c883b143ba2b8bfe2f2033d00dee9ff733f1b59c

    boolean submitted = false;
    try {
        byte[] encodedMessage = pdus.encodedMessage;
        // byte[0] = mtiByte
        // byte[1] = TP Message Reference
        // byte[2] = length of source phone
        // byte[3..length] = phone
        // protocol identifier
        int msgLen = encodedMessage[2] / 2;
        // +2 -> length of source phone
        // +2 -> for 91 after the length
        // +1 -> TP PID
        int indexTPDCS = msgLen + 5;
        byte TPDCS = encodedMessage[indexTPDCS];
        // System.out.println(TPDCS);
        System.out.println(getHexString(encodedMessage));
        byte[] changedMessage = encodedMessage.clone();
        // Set bit 4 to 1 using OR (|), indicating there is a message class
        // Set bit 0 and 1 to 0 using AND (&), indicating class 0
        byte newTPDCS = (byte) ((TPDCS | 0x10) & 0xFC); // Flash SMS
        changedMessage[indexTPDCS] = newTPDCS; // Class 0
        System.out.println(getHexString(changedMessage));
        // Log.d(SmsScheduler_TAG, getHexString(changedMessage));
        boolean send = true;
        if (send) {
            m2.invoke(m, pdus.encodedScAddress, changedMessage, null, null);

            // sendSMS(HexDump.bytesToHexString(pdus.encodedScAddress),
            // HexDump.bytesToHexString(changedMessage), null);

            String message = "Flash SMS sent to " + phone
                    + " successfully!";
            Toast notification = Toast.makeText(getBaseContext(), message,
                    Toast.LENGTH_SHORT);
            notification.show();
            Log.d(SmsScheduler_TAG, message);
            submitted = true;
        }
    } catch (IllegalArgumentException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (UnsupportedEncodingException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (IllegalAccessException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (InvocationTargetException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

            // not essential, saves the SMS sent. 
    if (submitted) {
        ContentValues values = new ContentValues();
        values.put(ADDRESS, phone);
        values.put(DATE, time);
        values.put(READ, 0);
        values.put(STATUS, -1);
        values.put(TYPE, MESSAGE_TYPE_SENT);
        values.put(BODY, sms);

        Uri inserted = getContentResolver().insert(
                Uri.parse("content://sms"), values);
    }

    // System.setSecurityManager(oldSM);

}
like image 38
chuacw Avatar answered Sep 17 '22 15:09

chuacw