ZombieLoad Attack
Return of the Leaking Dead
Watch out! Your processor resurrects your private browsing-history and other sensitive data.
After Meltdown, Spectre, and Foreshadow, we discovered more critical vulnerabilities in modern processors. The ZombieLoad attack allows stealing sensitive data and keys while the computer accesses them.
While programs normally only see their own data, a malicious program can exploit internal CPU buffers to get hold of secrets currently processed by other running programs. These secrets can be user-level secrets, such as browser history, website content, user keys, and passwords, or system-level secrets, such as disk encryption keys.
Update: L1D Eviction Sampling Leakage (CVE-2020-0549)
On January 27th, 2020, an embargo ended showing that the mitigations against MDS attacks released in May 2019 are insufficient. With L1D Eviction Sampling, an attacker can still mount ZombieLoad to leak data that is being evicted from the L1D cache.
We disclosed this issue to Intel on May 16th, 2019. However, as microcode updates containing the necessary fixes are not yet available, we are not releasing any proof-of-concept code.
We have described our findings already in the final version of our paper. If you want to learn more about this issue, we refer to Intel's Security Advisory.
The attack does not only work on personal computers but can also be exploited in the cloud. Please make sure to get the latest updates for your operating system!
@inproceedings{Schwarz2019ZombieLoad,
title = {{ZombieLoad}: Cross-Privilege-Boundary Data Sampling},
author = {Schwarz, Michael and Lipp, Moritz and Moghimi, Daniel and Van Bulck, Jo and Stecklina, Julian and Prescher, Thomas and Gruss, Daniel},
booktitle = {CCS},
year = {2019},
}Who is behind ZombieLoad?
Initial Report
ZombieLoad was discovered and reported by:
Scientific Analysis
The research team also includes:
ZombieLoad in Action
In our demo, we show how an attacker can monitor the websites the victim is visiting despite using the privacy-protecting Tor browser in a virtual machine.
Questions & Answers
If you have an Intel CPU, most certainly, yes.
With TSX Asynchronous Abort (CVE-2019-11135) that has been publicly disclosed on November 14th 2019, we show that the ZombieLoad attack is still possible on CPUs with hardware mitigations against MDS, e.g., recent Intel Cascade Lake CPUs. Furthermore, we show in the research paper that on some processors the software-based mitigations including the necessary microcode updates don't fully prevent the attack.
With L1D Eviction Sampling (CVE-2020-0549) that has been publicly disclosed on January 26th 2020, we demonstrate that the mitigations against ZombieLoad are incomplete and adversaries still leak data that is being evicted from the L1D cache.
L1D Eviction Sampling (CVE-2020-0549) is an issue that has been disclosed to the public on January 27th 2020. It shows that existing mitigations do not fully prevent leakage and an attacker can still mount the ZombieLoad attack.
We disclosed this issue to Intel on May 16th, 2019. We have described our findings already in the final version of our paper. If you want to learn more about this issue, we refer to Intel's Security Advisory.
Variant 2 or TAA is our new variant that has been disclosed on November 14th 2019. With this variant the ZombieLoad attack is still possible on CPUs with hardware mitigations against MDS, e.g., recent Intel Cascade Lake CPUs.
We disclosed Variant 2 to Intel on April 23th, 2019 and communicated that the attacks works on Cascade Lake CPUs on May 10th, 2019. On May 12th 2019, the variant has been put under embargo and, thus, has not been published with the previous version of our ZombieLoad attack on May 14th, 2019.
If you want to learn more, we welcome you to read the updated version of our publication or checkout Intel's One Pager, Deep Dive and Security Advisory Disclosure.
No. These are bugs in the processor. Software can work around these bugs, which costs performance. Future processors will have integrated fixes.
We do not have any data on this. The exploitation might not leave any traces in traditional log files.
While possible in theory, this is unlikely in practice. However, your antivirus may detect malware which uses the attacks by comparing binaries after they become known.
If your system is affected, our proof-of-concept ZombieLoad exploit can read data that is recently accessed or accessed in parallel on the same processor core.
We don't know.
Desktop, Laptop, and Cloud computers may be affected. More technically, we only verified the ZombieLoad attack on Intel processor generations released from 2011 onwards.
CVE-2018-12130 is the official reference to ZombieLoad and CVE-2019-11135 is the official reference to Variant 2 (TAA). CVE-2020-0549 is the official reference to L1D Eviction Sampling. CVE is the Standard for Information Security Vulnerability Names maintained by MITRE.
Acknowledgements
We would like to thank Intel for working with us during the responsible disclosure.
This work was supported in part by the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No 681402).
This work has been supported by the Austrian Research Promotion Agency (FFG) via the K-project DeSSnet, which is funded in the context of COMET – Competence Centers for Excellent Technologies by BMVIT, BMWFW, Styria and Carinthia.
The Graz University of Technology team would also like to thank Intel for providing a generous gift prior to the start of this research project, funding part of this research.
This research was partially supported by the Research Fund KU Leuven. Jo Van Bulck is supported by a grant of the Research Foundation - Flanders (FWO).