Feeds

Android app logs keystrokes using phone movements

Touchscreen side-channel hack

Seven Steps to Software Security

Computer scientists have developed an Android app that logs keystrokes using a smartphone's sensors to measure the locations a user taps on the touch screen.

TouchLogger, as their demo app is dubbed, allowed its creators at the University of California at Davis to demonstrate a vulnerability in smartphones and tablets that has largely gone unnoticed: While most of these devices lack physical keyboards that have long been known to leak user input, they nonetheless remain susceptible to monitoring through similar side-channel attacks.

Whereas eavesdroppers measure sound and electromagnetic emanation to capture input from traditional keyboards, they can monitor the motion of the device to achieve much the same result from a touch screen.

“Our insight is that motion sensors, such as accelerometers and gyroscopes, may be used to infer keystrokes,” the researchers wrote in a paper (PDF here) presented last week at the HotSec'11 workshop in San Francisco. “When the user types on the soft keyboard on her smartphone (especially when she holds her phone by hand rather than placing it on a fixed surface), the phone vibrates. We discover that keystroke vibration on touch screens are highly correlated to the keys being typed.”

Screen shot of Android data collecting app

User interface for data collection app

Applications like TouchLogger could be significant because they bypasses protections built into both Android and Apple's competing iOS that prevent a program from reading keystrokes unless it's active and receives focus from the screen. It was designed to work on an HTC Evo 4G smartphone. It had an accuracy rate of more than 70 percent of the input typed into the number-only soft keyboard of the device. The app worked by using the phone's accelerometer to gauge the motion of the device each time a soft key was pressed.

With minor refinements, the researchers believe they can expand the effectiveness of TouchLogger, as well as the devices it will work on.

“The tablet has a larger screen, so hopefully we can get a higher accuracy rate on a qwerty keyboard,” said Liang Cai, a graduate student in UC Davis's computer science department who collaborated with his advisor Hao Chen. “We didn't really try it on a large scale of devices.”

Besides targeting devices with larger touch screens, the researchers said TouchLogger could also be improved by tapping other sensors built into the targeted device. Prime candidates include gyroscopes to measure the rate of rotation and a camera to further detect motion. The scientists noted that the W3C recently published a specification for web applications to access accelerometer and gyroscope sensors using JavaScript. They are in the process of extending their work into a full research project.

For now, they hope to get the word out that the motion detected by a smart device's own sensors could expose highly valuable information, including passwords, social security numbers and credit card numbers.

“We hope to raise the awareness of motion as a significant side channel that may leak confidential data,” they wrote. ®

Mobile application security vulnerability report

More from The Register

next story
Yorkshire cops fail to grasp principle behind BT Fon Wi-Fi network
'Prevent people that are passing by to hook up to your network', pleads plod
HIDDEN packet sniffer spy tech in MILLIONS of iPhones, iPads – expert
Don't panic though – Apple's backdoor is not wide open to all, guru tells us
NEW, SINISTER web tracking tech fingerprints your computer by making it draw
Have you been on YouPorn lately, perhaps? White House website?
LibreSSL RNG bug fix: What's all the forking fuss about, ask devs
Blow to bit-spitter 'tis but a flesh wound, claim team
Attackers raid SWISS BANKS with DNS and malware bombs
'Retefe' trojan uses clever spin on old attacks to grant total control of bank accounts
Manic malware Mayhem spreads through Linux, FreeBSD web servers
And how Google could cripple infection rate in a second
Mozilla fixes CRITICAL security holes in Firefox, urges v31 upgrade
Misc memory hazards 'could be exploited' - and guess what, one's a Javascript vuln
Don't look, Snowden: Security biz chases Tails with zero-day flaws alert
Exodus vows not to sell secrets of whistleblower's favorite OS
prev story

Whitepapers

Designing a Defense for Mobile Applications
Learn about the various considerations for defending mobile applications - from the application architecture itself to the myriad testing technologies.
How modern custom applications can spur business growth
Learn how to create, deploy and manage custom applications without consuming or expanding the need for scarce, expensive IT resources.
Reducing security risks from open source software
Follow a few strategies and your organization can gain the full benefits of open source and the cloud without compromising the security of your applications.
Boost IT visibility and business value
How building a great service catalog relieves pressure points and demonstrates the value of IT service management.
Consolidation: the foundation for IT and business transformation
In this whitepaper learn how effective consolidation of IT and business resources can enable multiple, meaningful business benefits.