Compliant Product - Pixel 3/3XL
Certificate Date: 2019.07.19CC Certificate Security Target Validation Report
Validation Report Number: CCEVS-VR-VID10941-2019
Product Type: Mobility
Conformance Claim: Protection Profile Compliant
PP Identifier: Protection Profile for Mobile Device Fundamentals Version 3.1
Extended Package for Wireless LAN Client Version 1.0
CC Testing Lab: Gossamer Security Solutions
The Target of Evaluation (TOE) is Pixel 3 and Pixel 3 XL. The TOE is a mobile device to support enterprises and individual users alike. The Android 9.0 operating system includes a Linux 4.9 kernel. Additional libraries are provided to developers to help ensure secure application development and use for features such as Sensitive Data Protection.
The TOE provides a rich API to mobile applications and provides users installing an application the option to either approve or reject an application based upon the API access that the application requires (or to grant applications access at runtime).
The TOE also provides users with the ability to protect Data-At-Rest with AES encryption, including all user and mobile application data stored in the user’s data partition. The TOE uses a key hierarchy that combines a REK with the user’s password to provide protection to all user and application cryptographic keys stored in the TOE.
Finally, the TOE can interact with a Mobile Device Management (MDM) system (not part of this evaluation) to allow enterprise control of the configuration and operation of the device so as to ensure adherence to enterprise-wide policies (for example, restricting use of a corporate provided device’s camera, forced configuration of maximum login attempts, pulling of audit logs off the TOE, etc.) as well as policies governing enterprise applications and data (in a an employee-owned device [BYOD] scenario). An MDM is made up of two parts: the MDM agent and MDM server. The MDM Agent is installed on the phone as an administrator with elevated permissions (allowing it to change the relevant settings on the phone) while the MDM Server is used to issue the commands to the MDM Agent. Neither portion of the MDM process is considered part of the TOE, and therefore not being directly evaluated.
The TOE includes several different levels of execution including (from lowest to highest): hardware, a Trusted Execution Environment, Android’s Linux kernel, and Android’s user space, which provides APIs allowing applications to leverage the cryptographic functionality of the device.
Security Evaluation Summary
The evaluation was carried out in accordance to the Common Criteria Evaluation and Validation Scheme (CCEVS) requirements and guidance. The evaluation demonstrated that the TOE meets the security requirements contained in the Security Target. The criteria against which the TOE was judged are described in the Common Criteria for Information Technology Security Evaluation, Version 3.1, Revision 5, April 2017. The evaluation methodology used by the evaluation team to conduct the evaluation is the Common Methodology for Information Technology Security Evaluation, Evaluation Methodology, Version 3.1, Revision 5, April 2017. The product, when delivered and configured as identified in the Google Android 9.0 (Pixel 3/3XL) Guidance Documentation, Version 2.1, 07/16/2019, satisfies all of the security functional requirements stated in the Pixel 3 and Pixel 3 XL (MDFPP31/WLANCEP10) Security Target, Version 0.6, 07/17/2019. The project underwent CCEVS Validator review. The evaluation was completed in July 2019. Results of the evaluation can be found in the Common Criteria Evaluation and Validation Scheme Validation Report (report number CCEVS-VR-VID10941-2019) prepared by CCEVS.
The logical boundaries of the Pixel 3 and Pixel 3 XL are realized in the security functions that it implements. Each of these security functions is summarized below.
The TOE implements a security log, logcat, and intent logging that are each stored in a circular memory buffer of various sizes. An MDM agent can read/fetch the security log and intents and then handle appropriately (potentially storing the log to Flash or transmitting its contents to the MDM server).
The TOE includes multiple cryptographic libraries with CAVP certified algorithms for a wide range of cryptographic functions including the following: asymmetric key generation and establishment, symmetric key generation, encryption/decryption, cryptographic hashing and keyed-hash message authentication. These functions are supported with suitable random bit generation, key derivation, salt generation, initialization vector generation, secure key storage, and key and protected data destruction. These primitive cryptographic functions are used to implement security protocols such as TLS, EAP-TLS, IPsec, and HTTPS and to encrypt the media (including the generation and protection of data and key encryption keys) used by the TOE. Many of these cryptographic functions are also accessible as services to applications running on the TOE allowing application developers to ensure their application meets the required criteria to remain compliant to MDFPP standards.
User data protection:
The TOE controls access to system services by hosted applications, including protection of the Trust Anchor Database. Additionally, the TOE protects user and other sensitive data using encryption so that even if a device is physically lost, the data remains protected. The TOE’s evaluated configuration supports Android Enterprise profiles to provide additional separation between application and application data belonging to the Enterprise profile. Please see the Admin Guide for additional details regarding how to set up and use Enterprise profiles.
Identification and authentication:
The TOE supports a number of features related to identification and authentication. From a user perspective, except for FCC mandated (making phone calls to an emergency number) or non-sensitive functions (e.g., choosing the keyboard input method or taking screen shots), a password (i.e., Password Authentication Factor) must be correctly entered to unlock the TOE. Also, even when unlocked, the TOE requires the user re-enter the password to change the password. Passwords are obscured when entered so they cannot be read from the TOE's display and the frequency of entering passwords is limited and when a configured number of failures occurs, the TOE will be wiped to protect its contents. Passwords can be constructed using upper and lower cases characters, numbers, and special characters and passwords up to 16 characters are supported.
The TOE can also serve as an 802.1X supplicant and can both use X.509v3 and validate certificates for EAP-TLS, TLS, and HTTPS exchanges.
The TOE provides all the interfaces necessary to manage the security functions identified throughout this Security Target as well as other functions commonly found in mobile devices. Many of the available functions are available to users of the TOE while many are restricted to administrators operating through a Mobile Device Management solution once the TOE has been enrolled. Once the TOE has been enrolled and then un-enrolled, it will remove Enterprise applications and remove MDM policies.
Protection of the TSF:
The TOE implements a number of features to protect itself to ensure the reliability and integrity of its security features. It protects particularly sensitive data such as cryptographic keys so that they are not accessible or exportable through the use of the application processor’s hardware. The TOE disallows all read access to the Root Encryption Key and retains all keys derived from the REK within its the Trusted Execution Environment (TEE). Application software can only use keys derived from the REK by reference and receive the result.
The TOE also provides its own timing mechanism to ensure that reliable time information is available (e.g., for log accountability). It enforces read, write, and execute memory page protections, uses address space layout randomization, and stack-based buffer overflow protections to minimize the potential to exploit application flaws. It also protects itself from modification by applications as well as to isolate the address spaces of applications from one another to protect those applications.
The TOE includes functions to perform self-tests and software/firmware integrity checking so that it might detect when it is failing or may be corrupt. If any of the self-tests fail, the TOE will not go into an operational mode. It also includes mechanisms (i.e., verification of the digital signature of each new image) so that the TOE itself can be updated while ensuring that the updates will not introduce malicious or other unexpected changes in the TOE. Digital signature checking also extends to verifying applications prior to their installation as all applications must have signatures (even if self-signed).
The TOE can be locked, obscuring its display, by the user or after a configured interval of inactivity. The TOE also has the capability to display an administrator specified (using the TOE’s MDM API) advisory message (banner) when the user unlocks the TOE for the first use after reboot.
The TOE is also able to attempt to connect to wireless networks as configured.
The TOE supports the use of IEEE 802.11-2012, 802.1X, and EAP-TLS to secure communications channels between itself and other trusted network devices.