A tier-one mobile operator has selected Telsis’ SMS SafeGuard solution to block non-operator over-the-air (OTA) commands, in response to the recent “Nohl” SIM cards malware vulnerability alert.
German “ethical hacker” Karsten Nohl revealed on 23 July that he has uncovered a design flaw in over 750 million SIM cards that makes smartphone users vulnerable hack attacks.
In order to gain remote control of a device, the hacker sends an OTA command in the form of a hidden binary text message to the SIM card.
While the SIM card does not execute the command – the binary SMS is improperly signed, according to Nohl – it will respond to the hacker with an error code listing the cryptographic signature.
Once the hacker has the correct signature or “key”, a properly-signed binary SMS can be sent, which can download malicious Java applets onto the SIM card, which are enabled to send SMS, change voicemail numbers, query the phone’s location and many other functions.
There is also the possibility that such a malware could also gain access to payment credentials stored in the SIM cards of NFC-enabled devices with m-payments functionality.
Nohl also revealed that older SIM cards are also vulnerable to this form of malware attacks.
Services solution vendor Telsis says it has been pushing operators to prioritise transport layer protection for a while.
While the unnamed tier-one operator does not own any of the affected SIM cards, it has decided to deploy the vendor’s solution to protect its network.
“This is not about a single type of SIM. It’s about the wider issue of malware, and we believe that a strategy of patching weaknesses as and when they are found is always going to leave mobile network operators playing catch-up,” said Nigel Shaw, director of products, Telsis.
“Operators that fail to take active steps to properly secure their networks will miss out in three ways. They will lose profitability through fraud, lose the trust and business of organisations that want to use A2P messaging, and they will lose subscribers who will move to networks that offer better protection from spam messaging.”
The Telesis SMS SafeGuard sits alongside existing SMS network infrastructure, working at the transport layer of the network. By determining the actual source of inbound messages, the solution is able to block spam, malware and attempts made to avoid paying termination charges for bulk messaging.
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