In January 2018, the world learned about Spectre and Meltdown, a new class of issues that affects virtually all modern CPUs via nearly imperceptible changes to their micro-architectural states and can result in full access to physical RAM or leaking of state between threads, processes, or guests. In this session, we examine one of these side-channel attacks in detail and explore the implications for multi-tenant computing. We discuss AWS design decisions and what AWS does to protect your instances, containers, and function invocations. Finally, we discuss what the future looks like in the presence of this new class of issue.