Platform security: Mobile devices victimized
The first dings in BlackBerry’s tablet, PlayBook, occurred in December 2011 when a group of researchers published a tool that could jailbreak PlayBook tablets through the exploitation of a bug they found in the operating system. Research in Motion (RIM) later issued a fix for the jailbreak, but that was just the start of what may end up being a long road for the company’s security efforts.
The latest indication is work done by a pair of researchers who found a series of problems and weaknesses in PlayBook, including one that enables an attacker to listen in on the connection between the tablet and a BlackBerry handset. That connection, which occurs via Bluetooth in the company’s Bridge application, allows users to access their corporate email, calendar and other data on the tablet.
Researchers Zach Lanier and Ben Nell of Intrepidus Group were able to locate and grab the authentication token sent between the two devices during Bridge connections and, as an unprivileged user, connect to the PlayBook and access the user’s email and other sensitive information. The key to their finding is PlayBook’s OS puts the authentication token for the Bridge sessions in a spot readable by anyone who knows how to find it.
“While the Bridge is active, the token is in a place that is essentially world readable. The .all file being in a place that is world readable is the thing that causes the problem with the Bridge sessions,” Lanier said.
In order for their attack to work, certain conditions must be present. For example, an app that can access the token must be on the PlayBook. A malicious mobile app would satisfy that requirement. Or, if an attacker was able to exploit another flaw on the tablet, he would be able to access that token as well.
RIM said they will fix the Bridge flaw in version 2.0 of the tablet’s operating system.
“The BlackBerry PlayBook issue described at the Infiltrate security conference has been resolved with BlackBerry PlayBook OS 2.0, which is scheduled to be available as a free download to customers in February 2012. There are no known exploits, and risk is mitigated by the fact that a user would need to install and run a malicious application after initiating a BlackBerry Bridge connection with their BlackBerry smartphone.”
RIM is touting the PlayBook as the enterprise-ready tablet, and marketing it aggressively to its large installed BlackBerry customer base. The tablet doesn’t currently have a native email client, so users who want to read their corporate email on the PlayBook either need to use a webmail client or connect to their BlackBerry handsets using Bridge.
Given the placement of the Bridge token and its value to an attacker, Lanier and Nell expect the PlayBook to gain interest among researchers and attackers.
“Now, instead of it just being an unprivileged user who can get to this, now it becomes a high-value target to look for any other bugs in the PlayBook,” Nell said. “They’re protecting these really valuable assets with client-side controls.”