Researchers To Unleash New SMS Hacking Tool At Black Hat

Texting just keeps getting riskier: Researchers at next month's Black Hat USA in Las Vegas will demonstrate newly discovered threats to mobile phone users, as well as release a new iPhone application that tests phones for security flaws.

"We set out to create a graphical SMS auditing app that runs on the iPhone," says Luis Miras, an independent security researcher. The tool can test any mobile phone, not just the iPhone, for vulnerabilities to specific exploits that use SMS as an attack vector.

The researchers say they are currently working with mobile phone vendors on the bugs they discovered in their research, and say they expect the vendors to patch the flaws before Black Hat.

"In all of the issues, we're working through with responsible disclosure -- working with all of the [affected] vendors," says Zane Lackey, senior security consultant with iSEC Partners. "[And] they are going to be resolved with patched [phones]."

SMS has evolved into more than just simple text messaging, helping to make it an attractive vehicle for attacks. For example, new features allow graphics, sound, and video to be sent via the protocol. And SMS is live by default, so it requires almost no user interaction to be attacked. Miras and Lackey say the weaknesses they will expose are in specific SMS implementations, however, and not the protocol itself.

SMS hacking has captured the attention of security researchers lately. In March, Tobias Engel demonstrated an exploit that lets an attacker crash SMS text inboxes on several Nokia mobile phone models. Called the "Curse of Silence" attack, the exploit uses a specially crafted SMS message to launch a denial-of-service (DoS) attack on the victim's phone. While the SMS/MMS messaging features go dark, the phone itself remains operational after the attack.

And with mobile phones increasingly storing more sensitive personal and business information, they will inevitably become a bigger target for attackers, Lackey says. "SMS is interesting -- it's an 'always-on' attack surface," he says, and can be used for a DoS or for executing malware on a victim's phone, for example.

Mobile phones are also even more difficult than laptops to manage and protect, leaving them wide open to compromise. Unlike a company-issued laptop, however, mobile phones are sometimes privately owned by users and are under little or no corporate control, Miras says. The best way for users to protect themselves from SMS-based attacks today, he says, is to keep their phones patched.

But, he says, patching has always been a challenge for mobile phones "because of the many people involved -- the OS vendor, the OEM, and the carriers, which all have different aspects of control in the process," Miras says. "It's a difficult job, and it's still maturing."

Meanwhile, Miras and Lackey haven't yet christened their new SMS hacking tool with a catchy name. They also are writing some other minor tools for SMS security: "We're still working on those, but the [graphical SMS auditing app] is our flagship tool," Lackey says.

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