PRISM: Program Replication and Integration for Seamless MILS

Owen, C. A.; Grove, D. A.; Newby, Tristan; Murray, A.; North, Chris; Pope, Michael T.

doi:10.1109/sp.2011.15

Cited by 3 publications

(1 citation statement)

References 7 publications

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“…Historically, concern about timing channels was confined to high-assurance systems: certified separation kernels are required to limit their bandwidth [IAD] and the NSA provides guidance on how to avoid cache channels for systems built on secure realtime OSes [NSA]. While they remain a concern for modern highassurance systems [Owen et al, 2011], timing channels are now recognised as a threat to co-tenant cloud computing [Ristenpart et al, 2009], in which mutually distrusting tenants pay for access to common computing infrastructure. Hence timing channel mitigation has again become a hot topic in computer security [Kim et al, 2012;Stefan et al, 2013;Zhang and Reiter, 2013].…”

Section: Timing Channels: Backgroundmentioning

confidence: 99%

The Last Mile

Cock

Murray

et al. 2014

Proceedings of the 2014 ACM SIGSAC Conference on Computer and Communications Security

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Storage channels can be provably eliminated in well-designed, highassurance kernels. Timing channels remain the last mile for confidentiality and are still beyond the reach of formal analysis, so must be dealt with empirically. We perform such an analysis, collecting a large data set (2,000 hours of observations) for two representative timing channels, the locally-exploitable cache channel and a remote exploit of OpenSSL execution timing, on the verified seL4 microkernel. We also evaluate the effectiveness, in bandwidth reduction, of a number of black-box mitigation techniques (cache colouring, instruction-based scheduling and deterministic delivery of server responses) across a number of hardware platforms. Our (somewhat unexpected) results show that while these defences were highly effective a few processor generations ago, the trend towards imprecise events in modern microarchitectures weakens the defences and introduces new channels. This demonstrates the necessity of careful empirical analysis of timing channels.

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Section: Timing Channels: Backgroundmentioning

confidence: 99%