Microsoft has, or had, a similar technology they use internally, called TKO: <a href="https://www.microsoft.com/security/blog/2020/05/04/mitigating-vulnerabilities-endpoint-network-stacks" rel="nofollow">https://www.microsoft.com/security/blog/2020/05/04/mitigatin...</a><p>It's written in Rust and is based around a version of Bochs modified for deterministic execution. It's got time-travel debugging (with WinDbg), which works by replaying forward from the nearest snapshot to the point at which the user is asking to move backwards to.<p>The primary author of this software wanted to open source it, but the higher-ups at MSFT refused. He's been working on similar projects in a personal capacity though, e.g. <a href="https://gamozolabs.github.io/fuzzing/2020/12/06/fuzzos.html" rel="nofollow">https://gamozolabs.github.io/fuzzing/2020/12/06/fuzzos.html</a>