Researchers from Graz University of Technology and CISPA Helmholtz Center for Information Security have revealed the root cause behind several previously disclosed speculative execution attacks against modern processors, such as Meltdown and Foreshadow. The new research explains microarchitectural attacks were actually caused by speculative dereferencing of user-space registers in the kernel. Researchers also demonstrated that the Foreshadow vulnerability on Intel CPUs could be exploited even when the recommended mitigations are enabled. This is made possible due to the fact the attack can be mounted on data not residing in. kernel versions containing ‘prefetch’ gadgets.
Source: https://thehackernews.com/2020/08/foreshadow-processor-vulnerability.html