Messente avatar logo

Silent SMS: So quiet, that you will never hear it coming

- 5 MIN READ - 25 Aug 2013

Silent SMS: So quiet, that you will never hear it coming

If you have new voicemail, you get a notification on your phone. This is done by your Operator by sending an SMS that has special Data Coding parameter MWI (Message-waiting Indication). You don’t see the SMS in your inbox but your phone is able to read it and show the indicatio of new voicemail.

If you have access to SMPP supported SMS gateway, you can easily modify the same Data Coding parameter to send another kind of special SMS – “Silent” or “Invisible” SMS. The trick is to set Data Coding value to decimal 192 (hexadecimal 0xC0) and this way tell the phone to automatically discard the SMS and skip the inbox.

You still get Delivery Report that shows if the message was delivered to this phone or not, even though the owner of the phone has no idea about it. Neat.

How is “Silent SMS” used and what are the possible threats

Silent SMS is mostly used by bulk SMS providers for testing if the phone is reachable or just test out network quality but you can also make a smartphone app, that can intercept this kind of special SMS for some kind of hidden communication.

Also you have to be aware of the security issues – for example if you send constantly invisible SMS to a phone, it may be blocked from receiving other SMS or calls, as it is busy with Silent SMS.

Where to learn more technical details about the Silent SMS

For more details about Silent SMS and on how to send it, read “A Silent SMS Denial of Service (DoS) Attack” by N.J Croft and M.S Olivier. This study analyzes very well the variations and threats of Silent SMS.

Jaanus Rõõmus

Jaanus Rõõmus - CTO

Jaanus is co-founder and CTO of Messente and makes sure its wheels keep spinning and Messente always has a full tank of fuel.

Startup Conferences: What’s the point? (Slush 2017)

20 Oct 2017

With Slush coming up in about a month, it’s a good time ponder the purpose of large startup conferences. Many entrepreneurs head to conferences, like Slush, around the world and throughout the year looking for investments from venture capitalists and angel investors, yet there’s a lot more to gain from startup conferences. Think about it: there will be over 17,000 motivated and creative people in one place at one time. Get creative and gain as much as you can out of the experience.

Yuriy Mikitchenko

Yuriy Mikitchenko

The economics behind undelivered, failed SMS messages    

17 Oct 2017

The cost and full impact of undelivered or failed messages isn’t immediately clear. The financial impact is not simply the combination of the failed SMS and the cost to resend the message, which isn’t very much at times. There are other indirect costs that result from undelivered SMS messages that matter from a financial perspective. Let’s take a deeper look into the ripple effect of undelivered messages, which make the reasons behind our focus on SMS delivery quality even more clear.

Here are a few examples.

Uku Tomikas

Uku Tomikas

Fraud and Security: 2FA Considerations for PSD2

10 Oct 2017

The second Payment Services Directive (PSD2) is less than three months away from enforcement. While the regulation’s text is lengthy, a key component of the law is its extended reach in comparison to the first directive. PSD2 applies to all payment service providers and affiliates, including account information service providers and payment initiation service providers. In addition, the law applies when at least one part of the transaction is in the European Union. This means that payment service providers and their affiliates outside of the EU must comply with the law when the payer is in the EU. The additional geographical reach guarantees the same level of security expectations for all EU residents regardless of the location of the payment service provider.

Raili Liiva

Raili Liiva

Start sending messages to

for € N/A

Contact us