Cell-site simulators, often known as False Base Stations (FBS) or Stingrays, are radio gadgets that mimic actual cell websites in an effort to lure cell gadgets to connect with them. These gadgets are generally used for safety and privateness assaults, resembling surveillance and interception of communications. Lately, carriers have began reporting new varieties of abuse perpetrated with FBSs for the needs of economic fraud.
Specifically, there may be more and more extra proof of the exploitation of weaknesses in mobile communication requirements leveraging cell-site simulators to inject SMS phishing messages instantly into smartphones. This technique to inject messages fully bypasses the provider community, thus bypassing all the subtle network-based anti-spam and anti-fraud filters. Situations of this new kind of fraud, which carriers seek advice from as SMS Blaster fraud, have been reported in Vietnam, France, Norway, Thailand and a number of different nations.
GSMA’s Fraud and Safety Group (FASG) has developed a briefing paper for GSMA members to boost consciousness of SMS Blaster fraud and supply tips and mitigation suggestions for carriers, OEMs and different stakeholders. The briefing paper, accessible for GSMA members solely, calls out some Android-specific suggestions and options that may assist successfully shield our customers from this new kind of fraud.
What are SMS Blasters?
SMS Blaster is the time period that international carriers use to seek advice from FBS and cell-site simulators operated unlawfully with the objective of disseminating (blast) SMS payloads. The most typical use case is to leverage these gadgets to inject Smishing (SMS phishing) payloads into consumer gadgets. Fraudsters sometimes do that by driving round with transportable FBS gadgets, and there have even been experiences of fraudsters carrying these gadgets of their backpacks.
The tactic is easy and replicates identified methods to trick cell gadgets to an attacker-controlled 2G community. SMS Blasters expose a pretend LTE or 5G community which executes a single operate: downgrading the consumer’s connection to a legacy 2G protocol. The identical gadget additionally exposes a pretend 2G community, which lures all of the gadgets to connect with it. At this level, attackers abuse the well-known lack of mutual authentication in 2G and pressure connections to be unencrypted, which permits an entire Individual-in-the-Center (PitM) place to inject SMS payloads.
SMS Blasters are bought on the web and don’t require deep technical experience. They’re easy to arrange and able to function, and customers can simply configure them to mimic a selected provider or community utilizing a cell app. Customers also can simply configure and customise the SMS payload in addition to its metadata, together with for instance the sender quantity.
SMS Blasters are very interesting to fraudsters given their nice return on funding. Spreading SMS phishing messages generally yields a small return as it is extremely troublesome to get these messages to fly undetected by subtle anti-spam filters. A really small subset of messages finally attain a sufferer. In distinction, injecting messages with an SMS blaster fully bypasses the provider community and its anti-fraud and anti-spam filters, guaranteeing that each one messages will attain a sufferer. Furthermore, utilizing an FBS the fraudster can management all fields of the message. One could make the message appear like it’s coming from the reliable SMS aggregator of a financial institution, for instance. In a latest assault that impacted a whole lot of hundreds of gadgets, the messages masqueraded as a medical health insurance discover.
Though the kind of abuse carriers are uncovering not too long ago is monetary fraud, there may be precedent for the usage of rogue mobile base stations to disseminate malware, for instance injecting phishing messages with a url to obtain the payload. You will need to observe that customers are nonetheless weak to one of these fraud so long as cell gadgets assist 2G, whatever the standing of 2G of their native provider.
Android protects customers from phishing and fraud
There are a variety of Android-only security measures that may considerably mitigate, or in some instances absolutely block, the affect of one of these fraud.
Android 12 launched a consumer choice to disable 2G on the modem stage, a characteristic first adopted by Pixel. This feature, if used, fully mitigates the danger from SMS Blasters. This characteristic has been accessible since Android 12 and requires gadgets to evolve to Radio HAL 1.6+.
Android additionally has an choice to disable null ciphers as a key safety as a result of it’s strictly vital for the 2G FBS to configure a null cipher (e.g. A5/0) in an effort to inject an SMS payload. This safety characteristic launched with Android 14 requires gadgets that implement radio HAL 2.0 or above.
Android additionally gives efficient protections that particularly tackles SMS spam and phishing, no matter whether or not the supply channel is an SMS Blaster. Android has built-in spam safety that helps to establish and block spam SMS messages. Extra safety is offered by way of RCS for Enterprise, a characteristic that helps customers establish reliable SMS messages from companies. RCS for Enterprise messages are marked with a blue checkmark, which signifies that the message has been verified by Google.
We advocate leveraging a few vital Google security measures which can be found on Android, particularly Protected Shopping and Google Play Defend. As an extra layer of safety, Protected Shopping built-in on Android gadgets protects 5 billion gadgets globally and helps warn the customers about probably dangerous websites, downloads and extensions which might be phishing and malware-based.
Let’s say a consumer decides to obtain an app from the Play retailer however the app comprises code that’s malicious or dangerous, customers are protected by Google Play Defend which is a safety characteristic that scans apps for malware and different threats. It additionally warns customers about probably dangerous apps earlier than they’re put in.
Android’s dedication to safety and privateness
Android is dedicated to offering customers with a protected and safe cell expertise. We’re continuously working to enhance our security measures and shield customers from phishing, fraud, and different threats.
Working with international carriers and different OEMs by way of the GSMA to assist the ecosystem within the improvement and adoption of additional mobile safety and privateness options is a precedence space for Android. We look ahead to partnering with ecosystem companions in additional elevating the safety bar on this house to guard cell customers from threats like SMS blasters.
Thanks to all our colleagues who actively contribute to Android’s efforts in tackling fraud and FBS threats, and particular because of those that contributed to this weblog publish: Yomna Nasser, Gil Cukierman, Il-Sung Lee, Eugene Liderman, Siddarth Pandit.
