Security Evaluation of Scenarios Based on the TCG's TPM Specification

The Trusted Platform Module TPM is a basic but nevertheless very complex security component that can provide the foundations and the root of security for a variety of applications. In contrast to the TPM, other basic security mechanisms like cryptographic algorithms or security protocols have frequently been subject to thorough security analysis and formal verification. This paper presents a first methodic security analysis of a large part of the TPM specification. A formal automata model based on asynchronous product automata APA and a finite state verification tool SHVT are used to emulate a TPM within an executable model. On this basis four different generic scenarios were analysed with respect to security and practicability: secure boot, secure storage, remote attestation and data migration. A variety of security problems and inconsistencies was found. Subsequently, the TPM specification was adapted to overcome the problems identified. In this paper, the analysis of the remote attestation scenario and some of the problems found are explained in more detail.