IChannels: Exploiting current management mechanisms to create covert channels in modern processors

Authors: Jawad Haj-Yahya, Lois Orosa, Jeremie S. Kim, Juan Gómez Luna, A. Giray Yağlikçi, Mohammed Alser, Ivan Puddu, and Onur Mutlu
2021 ACM/IEEE 48th Annual International Symposium on Computer Architecture (ISCA)
PDF

Abstract

To operate efficiently across a wide range of workloads with varying power requirements, a modern processor applies different current management mechanisms, which briefly throttle instruction execution while they adjust voltage and frequency to accommodate for power-hungry instructions (PHIs) in the instruction stream. Doing so 1) reduces the power consumption of non-PHI instructions in typical workloads and 2) optimizes system voltage regulators’ cost and area for the common use case while limiting current consumption when executing PHIs.However, these mechanisms may compromise a system’s confidentiality guarantees. In particular, we observe that multilevel side-effects of throttling mechanisms, due to PHI-related current management mechanisms, can be detected by two different software contexts (i.e., sender and receiver) running on 1) the same hardware thread, 2) co-located Simultaneous Multi-Threading (SMT) threads, and 3) different physical cores.Based on these new observations on current management mechanisms, we develop a new set of covert channels, IChannels, and demonstrate them in real modern Intel processors (which span more than 70% of the entire client and server processor market). Our analysis shows that IChannels provides more than 24× the channel capacity of state-of-the-art power management covert channels. We propose practical and effective mitigations to each covert channel in IChannels by leveraging the insights we gain through a rigorous characterization of real systems.

People

BibTex

@inproceedings{haj-yahya2021ichannels,
  author    = {Haj-Yahya, Jawad and Orosa, Lois and Kim, Jeremie S. and Luna, Juan G{\'{o}}mez and Ya{\u{g}}lik{\c{c}}i, A. Giray and Alser, Mohammed and Puddu, Ivan and Mutlu, Onur},
  title     = {{IChannels: Exploiting current management mechanisms to create covert channels in modern processors}},
  booktitle = {2021 ACM/IEEE 48th Annual International Symposium on Computer Architecture (ISCA)},
  address   = {Online},
  year      = 2021,
  month     = jun,
  publisher = {IEEE},
  doi       = {10.1109/ISCA52012.2021.00081},
  url       = {https://doi.org/10.1109/ISCA52012.2021.00081}
}

Research Collection: 20.500.11850/505815