Subvisor: Reading an OpenVMM Guest Without Asking It Anything

Tue, 06 Oct 2026 00:00:00 +0200

First in a series on hypervisors, microVMs, confidential computing, and agent sandboxes — the machinery we are all quietly betting on to contain untrusted code, and how well it actually holds. Expect a lot of reading memory from outside the thing that owns it, and the occasional bug that falls out when you do.

Every memory forensics tool I have written starts at the same wall: you have the bytes, but the bytes do not explain themselves. DumpIt acquires the RAM; something still has to find the kernel inside it and name what it is looking at. On Windows that something is KdDebuggerDataBlock, the obfuscated structure a debugger decodes to bootstrap an analysis. On Linux, for a long time, it was “hope you have the matching System.map.”

ELF Core on Matt Suiche

Subvisor: Reading an OpenVMM Guest Without Asking It Anything