The latest Android iteration brings along a great deal of security improvements, including better encryption and authentication, Google says.
With Android 9 (also called Android Pie), the Internet search giant focused on aspects such as platform hardening, anti-exploitation, hardware-backed security, and user privacy, each with its own set of enhancements and new features.
Released this fall, the platform iteration brought updated File-Based Encryption, now offering support for external storage media. Metadata encryption with hardware support was also included, along with a new BiometricPrompt API, to have the biometric authentication dialogs that apps can display look the same.
There are also new protections for the Application Sandbox, with per-app cryptographic authentication to the sandbox, to improve app separation and prevent overriding safe defaults. Furthermore, apps are prevented from making data widely accessible.
Android Pie arrived with Control Flow Integrity (CFI) enabled by default within the media frameworks and other security-critical components, to prevent changes to the original control flow graph of compiled code. Google also added support for CFI to the Android kernel.
In a post published on Thursday, Google also underlines the presence of Integer Overflow Sanitization in Android 9, a security technique to mitigate memory corruption and information disclosure vulnerabilities that are the result of integer operations.
With Android Protected Confirmation, Android Pie provides OS API leveraging a hardware-protected user interface (Trusted UI) to perform critical transactions outside the main mobile operating system. The API allows developers to display a trusted UI prompt to the user and ask for approval of a sensitive transaction via a physical protected input.
A new Keystore type enhances protection of private keys via tamper-resistant hardware with dedicated CPU, RAM, and flash memory. Keystore also got improvements, including Keyguard-bound keys, Secure Key Import, 3DES support, and version binding, to better protect sensitive information and facilitate secure key use.
To boost user privacy, Google limited the access background apps have to the camera, microphone, and device sensors. The platform update arrived with new permission rules and permission groups for phone calls, phone state, and Wi-Fi scans, and with restrictions on information retrieved from Wi-Fi scans.
Now, Android supports encrypting backups with the user’s PIN, pattern, or password, so that an attacker can’t access a user’s backed-up application data without knowing the screen lock secret.
By default, Android Pie blocks all unencrypted HTTP traffic, in an attempt to push for the secure, HTTPS connections. With TLS on by default, users should be better protected from prying eyes. The platform also includes built-in support for DNS over TLS.