NewsMay 31, 2017 @ 6:31 AM

Cloak-and-Dagger Attack Creates Android Device Takeover Risk

Your Android device could be at risk from a new class of attack that allows for full takeover of the smartphone. Researchers at Georgia Tech recently discovered an attack known as Cloak and Dagger. It gives cyberattackers the opportunity to undertake malicious control of an Android device without users noticing the errant activity.

Overall, malicious malware is becoming a frequent issue in the app marketplace. Researchers recently uncovered several Android apps that masqueraded as a Funny Videos app on the Google Play Store but distributed a banking Trojan.

How Is Your Device Affected?

The Cloak and Dagger attack abuses a pair of legitimate app permissions that are used across certain features on Androids. These permissions are known as SYSTEM_ALERT_WINDOW (“draw on top”) and BIND_ACCESSIBILITY_SERVICE (“a11y”). The first permission allows apps to overlap on a device’s screen, and the second lets disabled users enter inputs via voice commands.

Abuse of these permissions makes it easier for cybercriminals to potentially develop and then submit a malicious app to Google Play Store. Mashable reported that an actor could use these accepted permissions paired with a “God-Mode” app to access messages and calls, keylog and clickjack a smartphone.

In this specific attack case, the user does not necessarily need to grant permission and is not even notified of a change in device behavior. In fact, the researchers performed a 20-person user study, and no one could detect malicious activity.

How Is the Issue Being Resolved?

These attacks affect all recent versions of Android, including 7.1.2, and researchers suggested that the flaws are not yet fixed. They also said the problem could be difficult to resolve because the issues involve two standard features in Android OS.

A Google spokesperson told The Register that the technology giant has been in close contact with the researchers in Georgia. The spokesperson added the company refreshed Google Play Protect to prevent the installation of malware and detect any similar malicious apps in the future.

Google said it already built new security protections into Android O that will strengthen protection in the future. However, Google O is scheduled for release later this year, and users will need to wait for higher levels of protection.

How Should Users React?

Georgia Tech said users should check which applications have access to the draw on top and the a11y permissions. They can also disable the draw on top permission used in Android 7.1.2.

The Hacker News explained the most comprehensive way to avoid hacking is to download apps from trusted and verified developers in the Google Play Store. The article also advised users to check for app permissions before installation.

News of this attack comes in the wake of a continuing run of stories involving mobile malware and banking Trojans. Users should stay alert to potential security risks and ensure app permissions are both monitored and restricted. If an app seems to ask for more permissions than necessary, avoid it all together.

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Mark Samuels

Tech Journalist

Mark Samuels is an experienced business technology journalist with an outstanding track record in research. He specializes in the role of chief information officers (CIOs) and is adept at helping executives understand the business benefits of complex technologies. Key areas of interest include innovation, digital transformation, cloud computing, mobility, information security, ecommerce and big data. Mark has written articles for national newspapers, including The Guardian, The Times and The Sunday Times. He has also produced features and columns for a range of IT trade publications, such as Computer Weekly, ZDNet, Tech Republic, IT Pro, Channel Pro, CBR and The Register.