Modernizing Authentication — What It Takes to Transform Secure Access
LAS VEGAS. Near Field Communication (NFC) is a short-range wireless technology that allows the latest generation of smart phones to communicate with other devices simply by placing them in close proximity to each other.
With NFC, the promise is that transactions with parking meters, snack machines, or anything else that requires payment or simple information transfer can be completed quickly and easily using nothing more than a mobile phone. In other words, the technology is likely to become a juicy target for hackers.
In front of a capacity crowd at the Black Hat security conference here in Las Vegas, security researcher Charlie Miller detailed and demonstrated new vulnerabilities in NFC. Currently, NFC is available on about 50 smart phones.
Miller explained that NFC is based on RFID and uses similar standards to that technology. The primary difference is that NFC is designed for close proximity with an operating range of about 4 centimeters.
"So lots of people think that no encryption is needed since no one will get that close," Miller said, as the audience laughed.
Miller then proceeded to show a number of videos of his own research in which he attempted to read an NFC card through a wallet that was sitting in another person's pocket. He referred to his actions as the wireless equivalent of credit card skimming.
NFC is only on when the phone is awake, Miller said. He added that's not really a problem as you can wake up a phone when it is asleep simply by sending a text message or a phone call and it wakes up the phone.
Miller noted that he ran at least 50,000 tests on the Galaxy Nexus to find NFC flaws. One of the NFC capabilities on Android is something known as Beam. In Android 4.0 (Ice Cream Sandwich), if you want to share a picture with another device it can be beamed over NFC. When sending, the sender has to click to send, but the recipient doesn't have to do anything. There are however only a limited number of applications that can receive Android Beam files and one of them is the default Android browser.
"So you could get near an NFC tag and then it could beam you a page link that shows up on your phone without interaction," Miller said. "For me, it's a little surprising that with a tag I can send you to a website."
Going a step further, the NFC Beam capability was then demonstrated to be somewhat more malicious when paired with a WebKit vulnerability in the Android browser. In the live demo, Miller demonstrated how simply receiving the web page could then trigger a Webkit browser flaw that enabled him to get full root shell access on an Android phone.
"It's a webkit bug, not an NFC bug and the real attack is the browser," Miller stressed. "But before you push a web page to me, for God's sake give me the option to say no."
Miller noted that NFC opens up a whole new attack surface for attackers. In a bid to help researcher and NFC vendors, Miller today is also releasing the tools he used to find bugs in the Android NFC implementation.