One man’s bug is another man’s feature.
- Meltdown affects effectively every Intel processor (unknown whether ARM and AMD are affected).
- Spectre affects Intel, AMD, and ARM processors.
- Cloud providers relying on containers that share one kernel, such as Docker, LXC, or OpenVZ are affected.
Meltdown breaks the most fundamental isolation between user applications and the operating system. This attack allows a program to access the memory, and thus also the secrets, of other programs and the operating system.
If your computer has a vulnerable processor and runs an unpatched operating system, it is not safe to work with sensitive information without the chance of leaking the information. This applies both to personal computers as well as cloud infrastructure. Luckily, there are software patches against Meltdown.
Spectre breaks the isolation between different applications. It allows an attacker to trick error-free programs, which follow best practices, into leaking their secrets. In fact, the safety checks of said best practices actually increase the attack surface and may make applications more susceptible to Spectre
Spectre is harder to exploit than Meltdown, but it is also harder to mitigate. However, it is possible to prevent specific known exploits based on Spectre through software patches.
There are VMware and other hypervisor security advisories [Security-announce] NEW VMSA VMSA-2018-0002 VMware ESXi, Workstation and Fusion updates address side-channel analysis due to speculative execution . XSA-254 - Xen Security Advisories