UMWAIT

This repository contains the experiments of evaluation and case studies discussed in the paper

• "(M)WAIT for It: Bridging the Gap between Microarchitectural and Architectural Side Channels" (USENIX Security'23).

You can find the paper at the USENIX website.

Tested Setup

We reverse engineer the memory-monitoring functions on Intel and AMD. All systems are running Ubuntu 20.04 LTS (Linux kernel 5.4).

The result shows that the Intel-specific variant UMONITOR/UMWAIT instructions help convert microarchitectural into architectural states, which are only available on Intel latest core processors (Tremont and Alder Lake).

In order to run the experiments and proof-of-concepts, the following prerequisites need to be fulfilled:

• Linux installation
  • Build tools (gcc, make)
  • PTEditor
  • Stress

Throughout our experiments, we successfully evaluated our implementations on the following CPUs. However, most of the implementation should work on CPUs with the same microarchitecture.

CPU	Microcode	Microarchitecture
Intel Celeron N4500	0x24000014	Jasper Lake
Intel Core i9-12900K	0xf	Alder Lake
Intel Core i7-8565U	0xec	Whiskey Lake
Intel Core i7-10710U	0xe8	Comet Lake
AMD Ryzen 5 2500U	0x810100b	Zen
AMD Ryzen 5 3550H	0x8108102	Zen+
AMD Ryzen 9 5900HX	0xa50000c	Zen3

Materials

This repository contains the following materials:

• Intel-umwait: contains the code that test if umonitor/umwait work on the current processor.
• trigger-tester: contains the code that we used to analyse the wakeup-trigger of all mwait- variants (Table 1-2).
• timed_mwait_feat: contains the code that we reverse engineered the Intel's undocumented timed-mwait feature.
• comparison: contains the code that we constructed a standard benchmark for detecting fully asynchronous events with Transient-Writes-Monitor (TWM) and other conventional side-channel attacks for reference (Figure 1-2, Table 3).
• covert_channel_eval: contains the code that we created a timer-less covert channel with umonitor/umwait (Figure 4).
• spectral: contains the code that we used the timer-less covert channel for spectre attacks (Figure 5-6).
• aes_example: contains the code that we reproduced attacks on AES T-table implementation based on our Timer-less Timing Measurement (Figure 3, 7).
• irq_monitor: contains the code that we can monitor network interrupts via the mwait- instructions on x86 and wfi instruction on arm.
• website_fingerprinting: contains the code that we detected network interrupts while opening a website (Figure 8).
• website_classify: contains the classifier for website classification (Figure 9).

Contact

If there are questions regarding these experiments, please send an email to ruiyi.zhang (AT) cispa.de or message @Rayiizzz on Twitter.

Research Paper

The paper is available at the USENIX website. You can cite our work with the following BibTeX entry:

@inproceedings{Zhang2023MWAIT,
  year={2023},
  title={{(M)WAIT for It: Bridging the Gap between Microarchitectural and Architectural Side Channels}},
  booktitle={USENIX Security},
  author={Ruiyi Zhang and Taehyun Kim and Daniel Weber and Michael Schwarz}
}

Disclaimer

We are providing this code as-is. You are responsible for protecting yourself, your property and data, and others from any risks caused by this code.