Android Phones' Fingerprint Sensors Vulnerable to Hackers

A flaw can allow hackers to copy images of a user's fingerprint from a phone's sensor and use it elsewhere with impunity.

Android security

Android users have a new security issue to worry about, this time involving fingerprint sensors that could allow hackers to copy a user's fingerprint image and use it to make purchases or conduct a wide range of supposedly secure transactions.

Researchers at FireEye discovered the flaw, called a "fingerprint sensor spying attack," which apparently gives hackers access to a vast amount of user fingerprints on Android mobile phones made by Samsung, HTC and Huawei, according to an Aug. 6 report by The Consumerist.

The researchers who found and reported the vulnerability, Tao Wei and Yulong Zhang, said that "because the devices' sensors aren't locked down by manufacturers, it creates a vulnerability that allows hackers to obtain images of users' fingerprints," according to the story.

Once the fingerprints are captured, the attackers are then able to use the images to impersonate the victim forever, the story states. The research identified the problem in mobile phones, but it could also be found in other devices that use fingerprint sensors, including laptops.

Zhang "couldn't specify which devices were more vulnerable to the hack, but did note that the iPhone was 'quite secure' because it encrypts fingerprint data," the story reported.

Device makers have since provided patches to repair the vulnerability after it was reported by the researchers.

In July, another Android flaw was discovered by researchers with security firm Zimperium that potentially exposed some 950 million users to risk. The vulnerability is found in the Android Stagefright media library, which is a common element in Android versions 2.2 and higher. That flaw involved MMS (Multimedia Messaging Service) messages that are sent to Android users, which are automatically processed with the Stagefright media library. The flaws in large part are integer overflows that lead to potentially exploitable memory buffer overflow conditions, according to a recent eWEEK report.

Earlier this week, Google announced that it is bolstering security in its Android mobile operating system through the introduction of new monthly security updates that will be issued over-the-air (OTA) to a wide range of Nexus mobile devices, according to an eWEEK report.

The first such security update began rolling out on Aug. 5 to devices including the Nexus 4, Nexus 5, Nexus 6, Nexus 7, Nexus 9, Nexus 10 and Nexus Player. The first security update includes fixes for issues reported since July 2015, including fixes for the libStageFright vulnerabilities. The fixes will also be released at the same time to the public via the Android Open Source Project. Nexus devices will continue to receive major updates for at least two years and security patches for three years from initial availability or 18 months from last sale of the device via the Google Store, whichever is longer.

The additional step is the latest in Android's arsenal to protect customers and their devices, according to Google.

In June, Google announced that it will pay thousands of dollars to researchers who find and report vulnerabilities in the Android mobile operating system as part of a new bug bounty program the company unveiled. The Android Security Rewards program builds on the format used in the company's well-known bug-hunting initiative for its Chrome Web browser. Software security researchers who find verifiable issues and disclose them by following the company's guidelines can earn up to $38,000 per issue. The program is part of Google's efforts to harden the Android platform.

Rewarding researchers for vulnerabilities is not a new idea. In 1995, Netscape kicked off an initiative to pay programmers for finding bugs in its pioneering Web browser software. In 2002, Verisign iDefense created the first third-party program, offering to pay researchers for information on bugs in popular enterprise software. Now, companies, such as HackerOne and Bugcrowd, offer third-party services to create and manage vulnerability-reward programs.

The Android Security Rewards program will be Google's third bug bounty initiative. The company has two other reward programs and paid out more than $1.5 million last year to researchers. Currently, Google pays for security vulnerabilities found in the Chrome Web browser under its Chrome Reward Program and the occasional Chromium competition. The Google Vulnerability Reward Program (VRP), its second bounty program, pays prize money to researchers who find flaws in the company's Websites, including, and Blogger.

With its latest bug bounty, the company will increase its payout to flaw finders for more detailed vulnerability submissions. The prizes start at $500 for a moderate issue, $1,000 for a highly severe issue and $2,000 for a vulnerability considered critical.