Any thoughts on UNIX security? I've been wondering what the most secure OS is for a long time, and the answer seems to be "systems that stopped being developed before you were born."
Android, iOS, and Chrome OS all have security models that are fundamentally superior to what you get on a base *nix system: Fine-grained, application-level permissions which the user can grant or deny on a case-by-case basis.
And before you say that all those operating systems are based on Unix; that's true but it's mostly just an implementation detail. There's no reason, for example, that Chrome OS couldn't be based on an entirely different kernel and still have the same permissions model, and most Unix-like systems don't have fine grained permissions like this out-of-the-box.
Windows Phone 7 did fine grained security much earlier and with full device encryption as default.
It's now also a standard on WinRT/UWP on Windows8/10.
Android was very late to the party regarding fine grained security. Google knowingly put billions of consumers at risk for a long time. And even today its security a nightmare.
> I've been wondering what the most secure OS is for a long time
Out of the box, most system with no public services running are usually decent (and that's hard to do with some systems). Beyond that it all comes down to configuration. There is no "most secure" OS. You can set them all up to be insecure or secure.
It was proven impossible to fully secure by high-assurance engineers back when INFOSEC was being invented. UNIX was much smaller back then. Project such as UCLA Secure UNIX and products such as Trusted Xenix were still unable to reach high assurance due to problems baked into the architecture and UNIX principles themselves. Even with API changes, they still had problems with covert channels. That led the inventors of INFOSEC to abandon UNIX for secure applications in favor of clean-slate, security kernels with user-mode or deprivileged layers for legacy, UNIX apps. Anything truly trustworthy runs directly on the security kernel.
re secure OS's
Probably INTEGRITY-178B or Turaya with Linux VM's for now. Maybe SourceT for network appliances. They're sold for nice sums of money to militaries, governments, and companies with nice budgets. GenodeOS is working toward a FOSS version of Nizza architecture.
Two of the original, high-assurance systems are still around for OEM license from BAE (STOP) and Aesec (GEMSOS). We've learned a lot of ways to break stuff since then. Who knows what current level of assurance is. ;)
Finally, there's CPU's designed to do isolation, reliability, and so on at the gate level. Rockwell-Collins uses one in their guards and crypto appliances. Sandia has a high-assurance Java CPU. Industry also sells Java CPU's for embedded that might be converted into some safe execution platform combined with something like JX. Call these building blocks for secure OS rather than the OS itself.
