[Terry_Roll]

The problem with cpu's is they dont know what instructions are supposed to run in order. Pipeline cache goes a little way towards getting the instructions in order, but ultimately a cpu does not know what instructions it has to run in order for a group of instructions to not be malicious. Think of a cpu like an old human telephone exchange where the operator is plugging in different cables to different sockets and hopefully you get the idea.

I'm amazed at the tech giants with all their funding and they still cant build secure operating systems or have the resources to reduce attack vectors within their own OS'es.

[pvg]

We've gone from 'every OS and device is easily exploitable' to mass market devices/OS pairings where drive-by exploits cost a million dollars.

[saagarjha]

You should look up Rice's theorem, because what you are suggesting is intractable and has nothing to do with the design of CPUs.

[Terry_Roll]

I wouldnt consider Rice's theorem to be relevant for what I was thinking. Sure all programs have common repeatable elements, like open a file, read/write, close file, so you wouldnt have an instruction or few out of the blue suddenly being run, in effect out of context, but thats whats happening here, the normal instructions that would be required to do a task, suddenly start using instructions that are not required in most cases before resorting back to the rest of the instructions for the original task.

Its abit like saying, would you expect some instructions for virtualisation to run if you load a jpg to display on screen? I wouldnt expect instructions for virtualisation functionality to be running in this example.

Or would I expect some instructions for encryption to run if I were to load a sound file to play over speakers? No I wouldnt expect that to happen, but thats the sort of thing thats happening here, some instructions not normally associated with a task are occurring, so how do you detect and alert and maybe halt those instructions?

There isnt anything in the CPU AFAIK that would pick this up, it would need the OS to act as a co-party to perhaps halt this, and I dont know if the OS or even AV software goes to this extent? At best, you'd have something like a dmesg feed or the Intel Processor Trace (https://news.ycombinator.com/item?id=30110088) to get the output of instructions being called (possibly independent of the OS), but like I say I dont know of any OS or AV product that goes to this level of monitoring.

Thats where I am coming from.