New Attack Threatens Android For Work Security

A newly discovered "app-in-the-middle" attack threatens the security of business data stored in Android for Work, which was designed to keep business and personal accounts separate.

The premise behind Android for Work, introduced in version 5.0 Lollipop, was to support the growth in bring-your-own-device (BYOD) policies. Users create two separate personas: a business persona with enterprise-level controls, and an open, unmanaged personal profile.

Enterprise apps, emails, and documents could be managed and secured through the business persona so admins wouldn't be able to monitor their personal apps. IT departments could manage their environments for work activities without restricting personal apps.

The platform relied on Android's user separation functionality, which allows different users to employ the same device. Work profiles are considered separate users, but they share icon badges and notifications with the personal profile.

It was a seemingly secure framework. Android for Work was created as an additional secure container so apps in the device's personal profile should not have any access to the activity or content in the business persona.

Unfortunately, this isn't the case. At this year's RSAC, Skycure will demonstrate how a vulnerability in the separation logic of Android for Work can let malicious personal apps to view, steal, and manipulate apps and content that should be secured in the business profile.

"We will show how a malicious app installed on the personal side, which should only be able to access personal apps, can easily watch everything a person does on their business persona and perform acts on their behalf," explains CTO and co-founder Yair Amit.

Skycure has been working with Google as part of a "coordinated disclosure" process through which users are informed of the flaw, which was discovered at the end of 2016 as Skycure was researching the security of mobile systems.

"It is imperative to share with the public the exposure," Amit continues. "Android for Work is a very good system with the premise of good security, but it puts the organization at stake when they have a lot of control over what goes on in the business persona, but no control over what goes on in the personal side. The damage is actually pretty high."

This technique is the "app-in-the-middle attack," which resides in the personal profile but can steal corporate data as users interact with it. Because IT admins can't monitor the personal profile from the work profile, they don’t know whether sensitive data has been exposed.

These attacks start by getting the victim to install a malicious personal app. The app uses system-level permissions built into Android -- notifications permissions, accessibility permissions -- to gain access to the business persona.

Once they have access to business apps, hackers can read emails, recover passwords to other systems, archive email, and perform a range of sensitive business activity. Victims have no clue they are under attack, says Amit. Attackers can gain access to more systems using this method.

One "app in the middle" attack is the Notification Access attack. Android for Work notifications are presented alongside personal notifications in the same interface. Because notifications access is a device-level permission, a malicious app in the personal profile can have permission to view and act on all notifications, including business alerts, because of the way it's designed.

There's also the Accessibility Permissions attack, which leverages Android's Accessibility Service to improve user interface interaction with features like audible narration of text for the visually impaired. The Accessibility Service has access to all device content and controls, so a personal app that acquires Accessibility permissions can also access apps in the business side.

This vulnerability poses a risk to businesses, especially as Google pushes Android as a business tool. The more organizations that use it, the bigger risk it is. "Everything you do in your persona is compromised in these attacks," Amit emphasizes.

There are steps businesses can take to mitigate the risk, he continues. In addition to employing a mobile defense system, Amit recommends educating employees of the danger. "Awareness is valuable," he notes, and organizations should be aware of the technical ramifications of these attacks.

*Google recently switched the branding of Android for Work and now calls it "work features in Android"

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