Let’s stop using the word “secure”. There is no “secure” in IT.
I know that sounds crazy, but it’s true.
Sometimes, when I speak to colleagues and customers, there will be non-technical or non-security people there, and they ask how to get a secure system. So I explain how I’d make a system secure. It goes a bit like this.
- Remove any non-critical USB connections: in particular external or “thumb” drives.
- Turn off all bluetooth.
- Turn off all wifi.
- Remove any network cables.
- Remove any other USB connections, including mouse or keyboard.
- Disconnect any monitors.
- Disconnect any other cables that are connected to the system.
- Yes, that includes the power cable.
- Now take out any hard drives – SSD, HDD or other.
- Destroy them. My preferred method is to gouge tracks in all spinning media, break the heads, bash all pieces with a hammer and then throw them into Mount Doom, but any other volcano[1] will do. Thermite lances are probably acceptable. You should do the same with all other components that you removed in earlier steps.
- Destroy the motherboard, including all chips and RAM.
- Tip all remaining pieces down a well.
- Pour concrete down the well.[2]
- You probably now have a secure which is about as secure as you’re going to get.
Yes, it’s a bit extreme, but the point is that all of the components there are possible threat vectors or information leakage channels.
Can we design and operate a system where we manage and mitigate the risks of threats and information leakage? Yes. That’s where we improve the security of a system. Is that a secure system? No, it’s not. What we’ve done is raise the bar, but we’ve not made it absolutely secure.
Part of the problem is that there’s just no way, these days[4], that any single person can be certain of the security of all parts of a system: they are just too many, and too complex. You may understand the application layer, but what about the virtualisation layer, for instance? I presented a simplified layer diagram in my post Isolationism a few months back, in which I listed the host as the bottom layer, but that was, of course, just asking for trouble. Along came Meltdown and Spectre, and now it’s clear (as if we didn’t know it already) that you should never ignore the fact that you can’t even trust the silicon you’re running on to do the thing you think it ought.
None of this, however, stops people and companies telling you that they’ll “secure your perimeter”, or provide you with “secure systems”. And it annoys me[5]. “We’ll help you secure your perimeter” isn’t too bad, but anything that suggests that you can have “secure systems” smacks to me of marketing – bad marketing.
So here you go: please stop using the word “secure” as an unqualified adjective or verb. We’re grown-ups, now, and we know it’s not real. So let’s not pretend.
Now – where was that well-cover? I need to deal with little Tommy.
1 – terrestrial/Middle Earth. I’m not sure about volcano temperatures on other planets or in the Undying Lands across the Western Sea.
2 – it should probably therefore be a disused well. Check there are no animals down there first[3]. In fact, before you throw anything down there.
3 – what’s that, Lassie? Little Tommy’s down the well? Well, I wonder whether little Tommy is waiting for us to throw the components down there so that he can do bad things. Bad Tommy.
4 – I’d like to think that maybe there was, once, in the distant past, but I’m probably kidding myself.
5 – you might be surprised at the number of things that annoy me[6].
6 – unless you’re my wife, in which case you probably won’t be[7].
7 – surprised. Or, in fact, reading this article.
Alice, Eve and Bob - a security blog 
We used a 55 gal. drum, with a blower feeding into the side, near the bottom of the barrel. Build a normal wood fire, turn on the blower and drop whatever components (for us it was hard drives) into the drum.
Most items turned into a thin layer of molten metal. Not only was it ‘secure’ but it was FUN.
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