A Platform Service for Remote Integrity Measurement and Attestation

Abstract

Software integrity measurement and attestation (M&A) are critical technologies for evaluating the trustworthiness of software platforms. To best support these technologies, next generation systems must provide a centralized service for securely selecting, collecting, and evaluating integrity measurements. Centralization of M&A avoids duplication, minimizes security risks to the system, and ensures correct administration of integrity policies and systems. This paper details the desirable features and properties of such a system, and introduces Maat, a prototype implementation of an M&A service that meets these properties. Maat is a platform service that provides a centralized policy-driven framework for determining which measurement tools and protocols to use to meet the needs of a given integrity evaluation. Maat simplifies the task of integrating integrity measurements into a range of larger trust decisions such as authentication, network access control, or delegated computations.

An infrastructure for faithful execution of remote attestation protocols

“…Integrity measurement tools include both static [26,36] and dynamic [6,15,19,37,38,41] approaches that support both baseline and recurring measurements of target systems. Higher-level measurement frameworks support userspace monitoring [28,12,24,29], kernel-level introspection [25], and attestation of embedded/IOT platforms [22,3,39]. The framework presented in the current work is designed as a common operational environment for such tools, plugging them in as ASPs and composing their measurement results as Copland Evidence.…”

Orchestrating Layered Attestations

“…2, is being utilized by the authors as a testing ground for Copland. Maat provides a pluggable interface for Attestation Service Providers (ASPs), functional units of measurement which are executed by Attestation Protocol Blocks (APBs) after a negotiation between an attester and appraiser machine [16]. Another architecture, given in [8], implements a policy mechanism designed to allow the appraiser to ask for different conditions to be satisfied by the target for different types of interactions.…”

“…We are actively exploring advanced attestation scenarios between Maat Attestation Managers (AMs). Recall from the introduction that Maat is a policy-based measurement and attestation (M&A) framework which provides a centralized, pluggable service to gather and report integrity measurements [16]. The Maat team is leveraging Copland to test attestation scenarios involving the configuration of multiple instances of Maat in multi-realm and multi-party scenarios.…”

“…In previous work, members of our team have taken a different approach. Maat is a policy-based measurement and attestation (M&A) framework which provides a centralized, pluggable service to gather and report integrity measurements [16]. Maat listens for attestation requests and can act as both an appraiser and an attester, depending on the needs of the current scenario.…”

Runtime Detection of Userspace Implants

“…In existing systems, most adversaries capable of modifying arbitrary processes are likely to be able to also modify the measurement tools or operating system kernel. To protect against realistic adversaries our approach relies on the concept of nested measurements and isolated execution environments provided by a measurement and attestation system such as Maat [25].…”