Cloaking Accessibility Events from Keyloggers

Learn to Prevent hackers from obtaining Accessibility-related permissions from the user in Android apps, in mobile CI/CD with a Data-Driven DevSecOps™ build system.

What are accessibility events?

Accessibility Events are events fired by the Android system when a notable change takes place in the user interface. Firing an event is performed by an Android View, which can fill the event with data about the UI change; for example, when a Button View was clicked or upon a text change in TextView Views.

The purpose of these events is to send notifications about UI changes to applications that use Accessibility Service. The enhanced capabilities of the user interface, which are integrated into the Accessibility Service, are generally meant to help users with disabilities interact with the application.

Why Cloak Accessibility Events?

Accessibility Events enable receiving data about most UI elements displayed on the app, which implemented the Accessibility Service class. Alternatively, these events enable obtaining the same data about other apps running on the device, if the data-receiving app has the appropriate permissions enabled.

By exploiting these the aforementioned capabilities, a potential attacker can disguise a malicious app as a seemingly innocent app. Then, after obtaining the Accessibility-related permissions from the user, the attacker can record View changes – particularly keystrokes – on other apps. In so doing, the attacker can collect highly confidential data items such as passwords and private personal information.

Developers can use this feature to cloak Accessibility Events so that those events cannot be read by attackers, keyloggers or other malware.

Prerequisites for Using Keylogging Prevention > Accessibility Events Cloaking:

To use Appdome’s mobile app security build system to Prevent hackers from obtaining Accessibility-related permissions from the user , you’ll need:

• Appdome account (create a free Appdome account here)
• A license for Keylogging Prevention > Accessibility Events Cloaking
• Mobile App (.apk or .aab for Android)
• Signing Credentials (see Signing Secure Android apps and Signing Secure iOS apps)

Prevent hackers from obtaining Accessibility-related permissions from the user on Android apps using Appdome

On Appdome, follow these 3 simple steps to create self-defending Android Apps that Prevent hackers from obtaining Accessibility-related permissions from the user without an SDK or gateway:

1. Upload the Mobile App to Appdome.

   1. Upload an app to Appdome’s Mobile App Security Build System

   2. Upload Method: Appdome Console or DEV-API
   3. Android Formats: .apk or .aab
   4. Keylogging Prevention > Accessibility Events Cloaking Compatible With: Java, JS, C++, C#, Kotlin, Flutter, React Native, Unity, Xamarin, Cordova and other Android apps

2. Build the feature: Keylogging Prevention > Accessibility Events Cloaking.

   1. Building Keylogging Prevention > Accessibility Events Cloaking by using Appdome’s DEV-API:

      1. Create and name the Fusion Set (security template) that will contain the Keylogging Prevention > Accessibility Events Cloaking feature as shown below:
      

      Figure 1: Fusion Set that will contain the Keylogging Prevention > Accessibility Events Cloaking feature
      Note: Naming the Fusion Set to correspond to the protection(s) selected is for illustration purposes only (not required).

      2. Follow the steps in Sections 2.2.1-2.2.2 of this article, Building the Keylogging Prevention > Accessibility Events Cloaking feature via Appdome Console, to add the Keylogging Prevention > Accessibility Events Cloaking feature to this Fusion Set.

      3. Open the Fusion Set Detail Summary by clicking the “...” symbol on the far-right corner of the Fusion Set, as shown in Figure 1 above, and get the Fusion Set ID from the Fusion Set Detail Summary (as shown below):

         Figure 2: Fusion Set Detail Summary
         Note: Annotating the Fusion Set to identify the protection(s) selected is optional only (not mandatory).

      4. Follow the instructions below to use the Fusion Set ID inside any standard mobile DevOps or CI/CD toolkit like Bitrise, App Center, Jenkins, Travis, Team City, Cirlce CI or other system:

         1. Build an API for the app – for instructions, see the tasks under Appdome API Reference Guide
         2. Look for sample APIs in Appdome’s GitHub Repository

   2. Building the Keylogging Prevention > Accessibility Events Cloaking feature via Appdome Console

      To build the Keylogging Prevention > Accessibility Events Cloaking protection by using Appdome Console, follow the instructions below.

      1. Where: Inside the Appdome Console, go to Build > Anti Fraud Tab > Secure Communication section.

         Like all other options in ONEShield™, Keylogging Prevention > Accessibility Events Cloaking is turned on by default, as shown below:

         Figure 3: Keylogging Prevention > Accessibility Events Cloaking option
         Note: The App Compromise Notification contains an easy to follow default remediation path for the mobile app end user. You can customize this message as required to achieve brand specific support, workflow or other messaging.

      2. How: Toggle (turn ON) Keylogging Prevention > Accessibility Events Cloaking, as shown below.

         Figure 3: Prevent hackers from obtaining Accessibility-related permissions from the user option

      3. When you select the Keylogging Prevention > Accessibility Events Cloaking you'll notice that your Fusion Set you created in step 2.1.1 now bears the icon of the protection category that contains Keylogging Prevention > Accessibility Events Cloaking

         

         Figure 4: Fusion Set that displays the newly added Keylogging Prevention > Accessibility Events Cloaking protection

      4. Click Build My App at the bottom of the Build Workflow (shown in Figure 3).

   Congratulations!  The Keylogging Prevention > Accessibility Events Cloaking protection is now added to the mobile app

3. Certify the Keylogging Prevention > Accessibility Events Cloaking feature in Android Apps.

   After building Keylogging Prevention > Accessibility Events Cloaking, Appdome generates a Certified Secure™ certificate to guarantee that the Keylogging Prevention > Accessibility Events Cloaking protection has been added and is protecting the app. To verify that the Keylogging Prevention > Accessibility Events Cloaking protection has been added to the mobile app, locate the protection in the Certified Secure™ certificate as shown below:

   Figure 5: Certified Secure™ certificate

   Each Certified Secure™ certificate provides DevOps and DevSecOps organizations the entire workflow summary, audit trail of each build, and proof of protection that Keylogging Prevention > Accessibility Events Cloaking has been added to each Android app. Certified Secure provides instant and in-line DevSecOps compliance certification that Keylogging Prevention > Accessibility Events Cloaking and other mobile app security features are in each build of the mobile app