A LOT OF concern about the NSA's seemingly omnipresent surveillance over the last year has focused on the agency's efforts to ...
A LOT OF concern about the NSA's seemingly omnipresent surveillance over the last year has focused on the agency's efforts to install back doors in software and hardware. Those efforts are greatly aided, however, if the agency can piggyback on embedded software already on a system that can be exploited.
Two researchers have uncovered such built-in vulnerabilities in a large number of smartphones that would allow government spies and sophisticated hackers to install malicious code and take control of the device.
The attacks would require proximity to the phones, using a rogue base station or femtocell, and a high level of skill to pull off. But it took Mathew Solnik and Marc Blanchou, two research consultants with Accuvant Labs, just a few months to discover the vulnerabilities and exploit them.
The vulnerabilities lie within a device management tool carriers and manufacturers embed in handsets and tablets to remotely configure them. Though some design their own tool, most use a tool developed by a specific third-party vendor—which the researchers will not identify until they present their findings next week at the Black Hat security conference in Las Vegas. The tool is used in some form in more than 2 billion phones worldwide. The vulnerabilities, they say, were found so far in Android and BlackBerry devices and a small number of Apple iPhones used by Sprint customers. They haven't looked at Windows Mobile devices yet.
The researchers say there's no sign that anyone has exploited the vulnerabilities in the wild, and the company that makes the tool has issued a fix that solves the problem. But it's now up to carriers to distribute it to users in a firmware update.
Carriers use the management tool to send over-the-air firmware upgrades, to remotely configure handsets for roaming or voice-over WiFi and to lock the devices to specific service providers. But each carrier and manufacturer has its own custom implementation of the client, and there are many that provide the carrier with an array of additional features.
To give carriers the ability to do these things, the management tool operates at the highest level of privilege on devices, which means an attacker who accesses and exploits the tool has the same abilities as the carriers.
The management tools are implemented using a core standard, developed by the Open Mobile Alliance, called OMA device management. From these guidelines, each carrier can choose a base set of features or request additional ones. Solnik says they found that some phones have features for remotely wiping the device or conducting a factory reset, altering operating system settings and even remotely changing the PIN for the screen lock.
They've also found systems that allow the carrier to identify nearby WiFi networks, remotely enable and disable Bluetooth or disable the phone's camera. More significantly, they've found systems that allow the carrier to identify the applications on a handset, as well as activate or deactivate them or even add and remove applications. The systems give the carrier the option of making these changes with our without prompting the consumer. Carriers also can modify settings and servers for applications pre-installed by the carrier—something hackers could exploit to force the phone to communicate with a server of their choosing.
Furthermore, some of the systems can monitor the web browser's home page and in some cases retrieve synced contacts. Others include a call redirect function that can direct the phone to a specific phone number. Carriers typically use this feature to program shortcuts to their own phone numbers. For example, Verizon might program its phones so "299" dials customer service. But Solnik found this feature can be used to redirect any number; phone numbers also can be programmed to launch an application.
"Pretty much whatever number … if we programmed it, when you dial it, it would do whatever functionality we programmed it to do," Solnik says. "Whether you have the number 1 programmed for your mother, it would then do what we choose.”
The more features the management tool offers the carrier, the more an attacker can do as well. But at a minimum, every device they examined would allow an attacker to change all of the cellular network functionality. In many cases, they could also control firmware updates.
And even the phones that use only the most basic management system have memory corruption vulnerabilities that would still allow a hacker to execute code or install malicious applications, they found.
Two phones that provided the highest level of exploitation were the HTC One M7 and the Blackberry Z10. Among iOS devices, they found that only iPhones offered by Sprint and running an operating system prior to version 7.0.4 were vulnerable. The 7.0.4 version of the software, which Apple released in November, partially solved the issue.
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