Over the past year, we have all heard about various hardware-level security vulnerabilities affecting the microprocessors that power our modern infrastructure.
Today, yet another set of vulnerabilities were disclosed, known as Microarchitectural Data Sampling (MDS) . These are similar to those we have seen before, but they involve different parts of the processor.
MDS is in fact a family of vulnerabilities in different (related) components of the processor. Unlike Meltdown, MDS doesn’t allow an attacker to directly control the target memory address from which they would like to leak data. Instead, MDS is a form of "sampling" attack in which an attacker is able to leverage cache side channel analysis in order to repeatedly measure the stale content of certain small internal processor buffers that are used to store data as it is being loaded into the caches or written back to memory. Through a sophisticated statistical analysis, it is possible to then reconstruct the original data.