Addressing the Department Gap in IoT Security

People in departments outside of IT aren’t paid to understand IT security. In the world of IoT, we need to make it easy for those people to do the right thing.

So, Mr. IT professional, you suffer from your colleagues at work connecting all sorts of crap to your network that you’ve never heard of?  You’re not alone.  As more and more devices hit the network, the ability to maintain control can often prove challenging.  Here are your choices for dealing with miscreant devices:

  1. Prohibit them and enforce the prohibition by firing anyone who attaches an unauthorized device.
  2. Allow them and suffer.
  3. Prohibit them but not enforce the prohibition.
  4. Provide an onboarding and approval process.

A bunch of companies I work with generally aim for 1 and end up with 3.  A bunch of administrators recognize the situation and fit into 2.  Everyone I talk to wants to find a way to scale 4, but nobody has, as of yet.  What does 4 involve?  Today, it means an IT person researching a given device, determining what networking requirements it has, creating firewall rules, and some associated policies, and establishing an approval mechanism for a device to connect.

This problem is exacerbated by the fact that many different enterprise departments have wide and varied needs, and the network stands as critical to many of them.  Furthermore, very few of those departments reports through the chief information officer, and chief information security officers often lack the attention their concerns receive.

I would claim that the problem is that incentives are not well aligned, were people in other departments even aware of the IT person’s concerns in the first place, and often they are not.  The person responsible for providing vending machines just wants to get the vending machines hooked up, while the person in charge of facilities just wants the lights to come on and the temperature to be correct.

What we know from hard experience is that the best way to address this sort of misalignment is to make it easy for everyone to do the right thing. What, then, is the right thing?

Prerequisites

It has been important pretty much forever for enterprises to be able to maintain an inventory of devices that connect to their networks.  This can be tied into the DHCP infrastructure or to the device authentication infrastructure.  Many such systems exist, the simplest of which is Active Directory.  Some are passive and snoop the network.  The key point is simply this: you can’t authorize a system if you can’t remember it.  In order to remember it, the device itself needs to have some sort of unique identifier.  In the simplest case, this is a MAC address.

Ask device manufacturers to help

Manufacturers need to make your life easier by providing you a description what the device’s communication requirements are.  The best way to do this is with Manufacturer Usage Descriptions (MUD).  When MUD is used, your network management system can retrieve a recommendation from the manufacturer, and then you can approve, modify, or refuse a policy.  By doing this, you don’t have to go searching all over random web sites.

Have a simple and accessible user interface for people to use

Once in place you now have a nice system that encourages the right thing to happen, without other departments having to do anything other than to identify the devices they want to connect.  That could be as simple as a picture of a QR code or otherwise entering a serial #.  The easier we can make it for people who know nothing about networking, the better all our lives will be.

MUD sliding along

Your chance to try and chime in on Manufacturer Usage Descriptions, a way to protect IoT devices.

You may recall that I am working on a mechanism known as Manufacturer Usage Descriptions (MUD).  This is the system by which manufacturers can inform the network about how best to protect their products.  The draft for this work is now about to enter “working group last call” at the IETF.  This means that now would be a very good time for people to chime in with their views on the subject.

In the meantime, MUD Maker has also been coming along. This is a tool that generates manufacturer usage descriptions.  You can find the tool here.

MUD isn’t meant to be the whole enchilada of IoT security.  Other tools are needed to authenticate devices onto the network, and to securely update them.  And manufacturers have to take seriously not only their customers’ needs, but what risk they may impose on others, as Mirai reminded us.  Had MUD been around at the time, it’s possible that Mirai would not have happened.

Home wireless security challenges for Things

It’s hard – but not impossible – for Things to connect to a home network in some sort of automated fashion.

WifiWhat’s the right way to connect a Thing to your home network?  Way back in the good old days, say last year, in order to connect a device to your home network, you could do it easily enough because the system had a display and a touch screen or a keyboard.  With many Things, there is no display and there is no keyboard, and some of the devices we are connecting may themselves not be that accessible to the home owner.  Think attic fans or even some light bulbs.  A means is needed first to tell these devices which network is the correct network to join, and then what the credentials for that network are.  In order to do any of this, there needs to be a way for the home router to communicate with the device in a secure and confidential way.  That means that each end requires some secret.  Public key cryptography is perfect for this, and it is how things would work in the enterprise.

WPA2 Enterprise makes use of individual keys and a flexible means to authenticate individuals and devices.  It looks a little like this:

EAP over Radius

EAP stands for Extensible Access Protocol, and it is just that.  There are many different authentication mechanisms available with EAP.   One method called EAP-TLS calls for both sides of the communication to transmit a certificate in an authentication transaction that contains their identities as certified by someone.  Initially, a device may be certified by its manufacturer, but then later it would use a certificate that is certified by the local network system.

A QR code

One challenge is getting the device certificate to be known by the network. One simple method to do this is to have an application tied to a camera that scans a QR code that points to a URL containing a signed copy of the device’s identity or certificate.  For instance, the QR code to the right encodes this URL:

https://www.ofcourseimright.com/qr/2834298343404739274639374630463934

which in turn gets you a certificate.  The next challenge is whether the device should trust the network. In the enterprise, there is a new approach being developed  known as Bootstrapping Remote Secure Key Infrastructures (BRSKI) (sometimes pronounced “brewski”).  In this case the manufacturer tells the device that the network is the correct one to join by essentially providing the device the network’s operational trust anchor.  This allows the device to validate the network’s certificate.

That’s something of a tall order even in the enterprise, but one that is worth aiming for.  If the home can leverage a service offered either by a service provider or by a new fangled home router company, if THEY can authenticate the home, and the manufacturer can authenticate them, then we have ourselves a ball game.  More work needed to get all the elements in place.