Spectre in the real world: Leaking your private data from the cloud with CPU vulnerabilities

Transient execution CPU vulnerabilities, like Spectre, have been making headlines since 2018. However, their most common critique is that these types of vulnerabilities are not really practical. Even though it is cool to leak `/etc/shadow` with a CPU bug, it has limited real-world impact. In this talk, we take Spectre out for a walk and let it see the clouds, by leaking memory across virtual machine boundaries at a public cloud provider, bypassing mitigations against these types of attacks. Our report was awarded with a $151,515 bug bounty, Google Cloud's highest bounty yet.