Feeds

Attack reads smudges to retrieve Android password patterns

Oily residue 'surprisingly persistent'

Internet Security Threat Report 2014

Smudges left on Android touch screens leave tell-tale signs that can often be used to recover password pattens used to lock the phones, according to research presented earlier this week.

The smudge attacks work by photographing Android handsets from a variety of angles using standard cameras and lights. The oily residues from fingers sliding across the touch-screen surface are then analyzed using standard computers running photo-editing software.

“We believe smudge attacks are a threat for three reasons,” the researchers wrote in a paper presented at the Fourth Usenix Workshop on Offensive Technologies, which took place on Monday in Washington DC.

“First, smudges are surprisingly persistent in time. Second, it is surprisingly difficult to incidentally obscure or delete smudges through wiping or pocketing the device. Third and finally, collecting and analyzing oily residue smudges can be done with readily-available equipment such as a camera and a computer.”

In one experiment that simulated an attack under ideal circumstances – in which touch screens weren't wiped – the researchers were able to recover the entire password pattern 68 per cent of the time if the phone first had been held to the user's face. Partial patterns were recovered 96 per cent of the time. Facial contact ensured there was enough skin oil to cause broad smudging, the researchers said.

A separate experiment, in which the touch screen was put in a user's pocket and allowed to move around slightly, was intended to simulate more realistic usage scenarios.

“Surprisingly, in all cases, the smudge was classified as perfectly retrievable,” the researchers wrote. “Simple clothing contact does not play a large role in removing smudges. However, on closer inspection, information was being lost. The directionality of the smudge often could no longer be determine [sic].”

Although the techniques could be applied to other types of smartphones, it was applied to two models of Android phones, which allow a user to trace a pattern on an on-screen 3x3 grid before the devices can be used. With 389,112 possible patterns, cracking the patterns would on average take many more attempts than the 20 unsuccessful tries permitted by the smartphone operating system. (After that, a user must enter credentials for a valid Google identity to access the phone.)

The experiments were carried out on two separate Android models, the HTC G1 and the HTC Nexus1. The researchers were Adam J. Aviv, Katherine Gibson, Evan Mossop, Matt Blaze and Jonathan M. Smith, and were all from the Computer and Information Science Department at the University of Pennsylvania. A PDF of their paper is here (warning: PDF). ®

Top 5 reasons to deploy VMware with Tegile

More from The Register

next story
UK smart meters arrive in 2020. Hackers have ALREADY found a flaw
Energy summit bods warned of free energy bonanza
DRUPAL-OPCALYPSE! Devs say best assume your CMS is owned
SQLi hole was hit hard, fast, and before most admins knew it needed patching
Knock Knock tool makes a joke of Mac AV
Yes, we know Macs 'don't get viruses', but when they do this code'll spot 'em
Feds seek potential 'second Snowden' gov doc leaker – report
Hang on, Ed wasn't here when we compiled THIS document
Mozilla releases geolocating WiFi sniffer for Android
As if the civilians who never change access point passwords will ever opt out of this one
Why weasel words might not work for Whisper
CEO suspends editor but privacy questions remain
prev story

Whitepapers

Why cloud backup?
Combining the latest advancements in disk-based backup with secure, integrated, cloud technologies offer organizations fast and assured recovery of their critical enterprise data.
Forging a new future with identity relationship management
Learn about ForgeRock's next generation IRM platform and how it is designed to empower CEOS's and enterprises to engage with consumers.
High Performance for All
While HPC is not new, it has traditionally been seen as a specialist area – is it now geared up to meet more mainstream requirements?
New hybrid storage solutions
Tackling data challenges through emerging hybrid storage solutions that enable optimum database performance whilst managing costs and increasingly large data stores.
Reducing the cost and complexity of web vulnerability management
How using vulnerability assessments to identify exploitable weaknesses and take corrective action can reduce the risk of hackers finding your site and attacking it.