Android browser flaw exposes user data

Potential harm is limited, however, by a few basic Android features. Here's how to protect your Android smartphone.

A vulnerability in the Android browser could permit an attacker to steal the user's local data, according to a report yesterday from security expert, Thomas Cannon.

Specifically, a malicious Website could use the flaw to access the contents of files stored on the device's SD card as well as "a limited range of other data and files stored on the phone," Cannon explained.

In essence, the problem arises because the Android browser doesn't prompt the user when downloading a file. "This is a simple exploit involving JavaScript and redirects, meaning it should also work on multiple handsets and multiple Android versions without any effort," he noted.

A video included with Cannon's post demonstrates the exploit in action using the Android emulator with Android 2.2, or Froyo, but Cannon has found it on an HTC Desire with Android 2.2 as well. Heise Security was able to reproduce the exploit on both a Google Nexus One and a Samsung Galaxy Tab, both running Android 2.2, according to a report on The H.

For the demo, Cannon first created a file on the SD card of the Android device. Next, he visited a malicious page and watched as it grabbed the file and automatically uploaded it to a server.

Protective Measures

The Android Security Team responded within 20 minutes of Cannon's notification about the flaw and is planning a fix that will go into a Gingerbread maintenance release after that version becomes available, he said. An initial patch has already been developed and is now being evaluated.

In the meantime, since not all gadget manufacturers provide timely Android updates, Cannon suggests a few steps users can take to protect themselves, including:

* Disabling JavaScript in the browser.

* Watching for suspicious automatic downloads, which should be flagged in the notification area. "It shouldn't happen completely silently," Cannon notes.

* Using a browser such as Opera Mobile, which prompts the user before downloading files.

* Unmounting the SD card.

The Android Advantage

Though it is clearly a vulnerability that needs to be addressed, there is good news in Cannon's discovery as well.

First, "it is not a root exploit, meaning it runs within the Android sandbox and cannot grab all files on the system," Cannon pointed out. Rather, it exposes only files on the SD card and "a limited number of others." System directories, in other words, remain protected.

Second, "you have to know the name and path of the file you want to steal," he added.

In other words, Android's Linux roots serve to protect the user from anything more than local damage, and that damage is limited to files whose names and paths are predictable, such as pictures taken with the device's camera.

Follow Katherine Noyes on Twitter: @Noyesk.

Join the CSO newsletter!

Error: Please check your email address.

Tags online securityopen sourceconsumer electronicsapplicationsGooglebrowser securityCell PhonesPhonesbrowserssoftware

More about GalaxyGoogleHTCLinuxSamsung

Show Comments

Featured Whitepapers

Editor's Recommendations

Solution Centres

Stories by Katherine Noyes

Latest Videos

  • 150x50

    CSO Webinar: Will your data protection strategy be enough when disaster strikes?

    Speakers: - Paul O’Connor, Engagement leader - Performance Audit Group, Victorian Auditor-General’s Office (VAGO) - Nigel Phair, Managing Director, Centre for Internet Safety - Joshua Stenhouse, Technical Evangelist, Zerto - Anthony Caruana, CSO MC & Moderator

    Play Video

  • 150x50

    CSO Webinar: The Human Factor - Your people are your biggest security weakness

    ​Speakers: David Lacey, Researcher and former CISO Royal Mail David Turner - Global Risk Management Expert Mark Guntrip - Group Manager, Email Protection, Proofpoint

    Play Video

  • 150x50

    CSO Webinar: Current ransomware defences are failing – but machine learning can drive a more proactive solution

    Speakers • Ty Miller, Director, Threat Intelligence • Mark Gregory, Leader, Network Engineering Research Group, RMIT • Jeff Lanza, Retired FBI Agent (USA) • Andy Solterbeck, VP Asia Pacific, Cylance • David Braue, CSO MC/Moderator What to expect: ​Hear from industry experts on the local and global ransomware threat landscape. Explore a new approach to dealing with ransomware using machine-learning techniques and by thinking about the problem in a fundamentally different way. Apply techniques for gathering insight into ransomware behaviour and find out what elements must go into a truly effective ransomware defence. Get a first-hand look at how ransomware actually works in practice, and how machine-learning techniques can pick up on its activities long before your employees do.

    Play Video

  • 150x50

    CSO Webinar: Get real about metadata to avoid a false sense of security

    Speakers: • Anthony Caruana – CSO MC and moderator • Ian Farquhar, Worldwide Virtual Security Team Lead, Gigamon • John Lindsay, Former CTO, iiNet • Skeeve Stevens, Futurist, Future Sumo • David Vaile - Vice chair of APF, Co-Convenor of the Cyberspace Law And Policy Community, UNSW Law Faculty This webinar covers: - A 101 on metadata - what it is and how to use it - Insight into a typical attack, what happens and what we would find when looking into the metadata - How to collect metadata, use this to detect attacks and get greater insight into how you can use this to protect your organisation - Learn how much raw data and metadata to retain and how long for - Get a reality check on how you're using your metadata and if this is enough to secure your organisation

    Play Video

  • 150x50

    CSO Webinar: How banking trojans work and how you can stop them

    CSO Webinar: How banking trojans work and how you can stop them Featuring: • John Baird, Director of Global Technology Production, Deutsche Bank • Samantha Macleod, GM Cyber Security, ME Bank • Sherrod DeGrippo, Director of Emerging Threats, Proofpoint (USA)

    Play Video

More videos

Blog Posts

Market Place