SMS spoofing

SMS spoofing is a relatively new technology which uses the short message service (SMS), available on most mobile phones and personal digital assistants, to set who the message appears to come from by replacing the originating mobile number (Sender ID) with alphanumeric text. Spoofing has both legitimate uses (setting the company name from which the message is being sent, setting your own mobile number, or a product name) and illegitimate uses (such as impersonating another person, company, product).

How SMS spoofing is carried out

SMS Spoofing occurs when a fraudster manipulates address information in order to impersonate a user that has roamed onto a foreign network and is submitting messages to the home network. Frequently, these messages are addressed to destinations outside the home network – with the home SMSC essentially being “hijacked” to send messages into other networks.

The impact of this fraud is threefold:

1. The home network can incur termination charges caused by the delivery of these messages to interconnect partners. This is a quantifiable revenue leakage.

2. These messages can be of concern to interconnect partners. Their customers may complain about being spammed, or the content of the messages may be politically sensitive. Interconnect partners may threaten to cut-off the home network unless a remedy is implemented. Home subscribers will be unable to send messages into these networks.

3. While fraudsters normally used spoofed-identities to send messages, there is a risk that these identities may match those of real home subscribers. The risk therefore emerges, that genuine subscribers may be billed for roaming messages they did not send. If this situation occurs, the integrity of the home operator’s billing process may be compromised, with potentially huge impact on the brand. This is a major churn risk.

An SMS Spoofing attack is often first detected by an increase in the number of SMS errors encountered during a bill-run. These errors are caused by the spoofed subscriber identities. Operators can respond by blocking different source addresses in their Gateway-MSCs, but fraudsters can change addresses easily to by-pass these measures. If fraudsters move to using source addresses at a major interconnect partner, it may become unfeasible to block these addresses, due to the potential impact on normal interconnect services [ [http://www.openmindnetworks.com/SMSSpoofing.asp An overview on how to stop SMS Spoofing in mobile operator networks (September 9, 2008)] ] .

Legality

The UK premium rate regulator, PhonepayPlus (formerly ICSTIS) recently concluded a public consultation on anonymous SMS, in which they stated they were not averse to the operation of such services. However, from 2008 PhonePayPlus are introducing new regulation covering anonymous SMS which will require anonymous SMS service providers to send a follow-up message to the recipient stating that a spoofed SMS has been sent to them, and operate a complaints helpline. It is illegal in Australia.

Protecting users from SMS spoofing

If a user can prove that their SMS sessions have been spoofed, they should contact both law enforcement and their cellular provider, who should be able to track where the SMS messages were actually sent from. A user may also modify the phone's settings so that only messages from authorized numbers are allowed. Unfortunately, this is not always effective since hackers could be impersonating the user's friends as well.

Examples of SMS spoofing

* Messages sent from Google are sent with the Sender ID "Google".

* Skype sends messages from its users with the mobile number they registered with. Note that when a user attempts to "reply" to the SMS, the local system may or may not allow the replying message to be sent through to the spoofed "origin."

The Asian School of Cyber Laws (Pune) recently conducted experiments in SMS spoofing at the national and international level. They were able to successfully spoof SMS messages and make them appear to come from other people's cellular phones. These people were using GSM based cellular phone services in various parts of India and other Asian as well as African countries.

Nitesh Dhanjani discovered a security vulnerability when sending a spoofed SMS message to Twitter. Twitter used the SMS originator to authenticate the user. Nitesch used [http://www.hoaxmail.co.uk hoaxmail.co.uk] to spoof the SMS message and therefore could trick Twitter to post the message on the victims Twitter page.

References

External links

* [http://www.crime-research.org/interviews/sms-spoofing-intro/ SMS spoofing - Q&A with Computer Crime Research Center staff]

* [http://www.openmindnetworks.com/uploads/documents/news/SMS%20Spoofing%20l%20White%20Paper.pdf The Threat of SMS Spoofing:Prevent Revenue Loss by Securing The Network Against Fraudulent Attack]