Overview

On May 14, 2019, Intel and other industry partners shared details and information about a new group of vulnerabilities collectively called Microarchitectural Data Sampling (MDS).

First identified by Intel’s internal researchers and partners, and independently reported to Intel by external researchers, MDS is a subclass of previously disclosed speculative execution side channel vulnerabilities and is comprised of four related techniques. Under certain conditions, MDS potentially provides a malicious program the means to read data that the program otherwise would not be able to see. MDS techniques are based on sampling data leaked from small structures within the CPU using a locally executed speculative execution side channel. MDS does not, by itself, provide malicious actors the ability to choose which data is leaked using these methods. Practical exploitation of MDS is a very complex undertaking.

Starting with select 8th and 9th Generation Intel® Core™ processors, as well as the 2nd Generation Intel® Xeon® processor Scalable family, MDS is mitigated in hardware. More details can be found here. We expect all future Intel® processors include hardware mitigations addressing these vulnerabilities.

The Transactional Asynchronous Abort (TAA) vulnerability affects the same microarchitectural structures as MDS but uses a different mechanism for the exploit. On CPUs that are vulnerable to MDS, the existing MDS mitigation helps address the TAA CVE vulnerability. On CPUs that are not vulnerable to MDS but have transactional functionality, additional mitigation might be required. Additional details can be found here.