Privilege-Based Remote Attestation
Tobias Rauter, Andrea Höller, Nermin Kajtazović, Christian Kreiner · 2015
Remote attestation is used to assure the integrity of a trusted platform (prover) to a remote party (challenger). Traditionally, plain binary attestation (i.e., attesting the integrity of software by measuring their binaries) is the method of choice. Especially in the resource-constrained embedded domain with the ever-growing number of integrated services per platform, this approach is not feasible since the challenger has to know all possible 'good' configurations of the prover. In this work, a new approach based on software privileges is presented. It reduces the number of possible configurations the challenger has to know by ignoring all services on the prover that are not used by the challenger. For the ignored services, the challenger ensures that they do not have the privileges to manipulate the used services. To achieve this, the prover measures the privileges of its software modules by parsing their binaries for particular system API calls. The results show significant reduction of need-to-know configurations. The implementation of the central system parts show its practicability, especially if combined with a fine-grained system API.