Android Takeover With The Swipe Of A Smartphone

BLACK HAT USA -- Las Vegas, NV -- Emerging near-field communication (NFC) technology for reading tags and paying electronically for cab fare can be abused to wrest control of some Android phones, a researcher demonstrated here today.

Charlie Miller, who is a managing principal with Accuvant Labs, discovered several vulnerabilities in certain Android smartphones and released a homegrown fuzzer for devices enabled with NFC, an RFID-based technology that shares information between smartphones and related devices when swiped within a few centimeters of one another.

"NFC opens a new wave of server-side attacks, without user interaction," Miller said in his presentation here. The researcher discovered flaws in the Samsung Nexus 5 Galaxy Android version 2.3.3 (a.k.a. Gingerbread) and Nokia n9.1.2 Android Version 4.0.1 (a.k.a. Ice Cream Sandwich), which he then reported to the vendors. The Android 4.0.1 flaw was actually in the Web kit browser, and Google has since fixed it without Miller's help.

Trouble is, most Android users have not upgraded to the new version of the smartphone OS, Miller notes.

[ Renowned researcher will show just how dangerous it can be to pay cab fare with your mobile device, as he demonstrates vulnerabilities he discovered in emerging near-field communications (NFC) technology. See Apple Ban Gives Miller Time To Hack Other Things. ]

The browser is the real attack surface for NFC-enabled smartphones, says Miller, who says he moved on from the low-level bug exploration to the browser in his research when that became evident. Along with fellow Accuvant researcher Josh Drake and George Wicherski from CrowdStrike, Miller demonstrated a live exploit developed by Drake and Wicherski where Wicherski waved his Android near Drake's and took over the device. The attack exploits a bug in the Webkit browser.

"This is sort of frightening," Miller said. "I can get shell and all I did was get near the phone."

Miller also found PowerPoint and PDF bugs in the Nokia N9 1.2 Harmattan PR 1.2, and he says as far as he knows, Nokia has not yet fixed them.

NFC is not widely deployed today, but it does come enabled out of the box in Android devices. But the good news is you can always turn NFC off, says Miller, who says he disables the technology in his smartphones not because he's worried about its risks, but mainly because he doesn't have any actual use for it.

"Not everyone has NFC, so it's not really a huge risk. This is more of a cautionary tale," he says. Miller says the bugs in NFC demonstrate how adding more complexity to these devices also raises potential risks of abuse.

In his presentation, Miller noted that NFC only works when a smartphone is awake, but an attacker could "wake it up" by sending a text message, for instance.

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