Spectre and Meltdown: An insider’s guide
February 4, 2019
Design flaws in modern chip design have emerged as a significant threat to the security of data on PCs and mobile devices. This comprehensive ebook delves into two prominent vulnerabilities—Spectre and Meltdown—and their many variants. It explains how they work, the products that are affected, and steps being taken to mitigate the risks.
From the ebook:
What are Spectre and Meltdown?
In the most basic definition, Spectre is a vulnerability allowing for arbitrary locations in the allocated memory of a program to be read. Meltdown is a vulnerability allowing a process to read all memory in a given system. Spectre and Meltdown are not singular flaws—they individually represent a class of closely related variants.
Spectre and Meltdown are uniquely dangerous security vulnerabilities that allow malicious actors to bypass system security protections present in nearly every recent device with a CPU—not just PCs, servers, and smartphones, but also Internet of Things (IoT) devices, like routers and smart TVs. By leveraging these vulnerabilities, it is possible to read protected system memory, gaining access to passwords, encryption keys, and other sensitive information.
Spectre and Meltdown are representative examples of “transient execution” attacks, which rely on hardware design flaws in the implementation of speculative execution, instruction pipelining, and out-of-order execution in modern CPUs. While this trio is essential to performance optimizations inherent in modern processors, their implementations vary between CPU manufacturers and microarchitectures. As a result, not all Spectre and Meltdown variants are exploitable on all microarchitectures.