AMD: Microcode Signature Verification Vulnerability
github.com
### Summary Google Security Team has identified a security vulnerability in some AMD Zen-based CPUs. This vulnerability allows an adversary with local administrator privileges (ring 0 from outside...

for readers missing the significance of the number 4 in the proof of concept: to demonstrate this vulnerability the researchers created a microcode update which replaces the “hardware” random number generator behind the RDRAND instruction with an implementation of xkcd#221 😭