Shadow Devices: The Exponentially Expanding Attack Surface [New Series]By Mike Rothman
One of the challenges of being security professionals for decades is that we actually remember the olden days. You remember, when Internet-connected devices were PCs; then we got fancy and started issuing laptops. That’s what was connected to our networks. If you recall, life was simpler then. But we don’t have much time for nostalgia. We are too busy getting a handle on the explosion of devices connected to our networks, accessing our data.
Here is just a smattering of what we see:
- Mobile devices: Supporting smartphones and tablets seems like old news, mostly because you can’t remember a time when they weren’t on your network. But despite their short history, their impact on mobile networking and security cannot be understated. What’s more challenging is how these devices can connect directly to the cellular data network, which gives them a path around your security controls.
- BYOD: Then someone decided it would be cheaper to have employees use their own devices, and Bring Your Own Device (BYOD) became a thing. You can have employees sign paperwork giving you the ability to control their devices and install software, but in practice they get (justifiably) very cranky when they cannot do something on their personal devices. So balancing the need to protect corporate data against antagonizing employees has been challenging.
- Other office devices: Printers and scanners have been networked for years. But as more sophisticated imaging devices emerged, we realized their on-board computers and storage were insecure. They became targets, attacker beachheads.
- Physical security devices: The new generation of physical security devices (cameras, access card readers, etc.) is largely network connected. It’s great that you can grant access to a locked-out employee, from your iPhone on the golf course, but much less fun when attackers grant themselves access.
- Control systems and manufacturing equipment: The connected revolution has made its way to shop floors and facilities areas as well. Whether it’s a sensor collecting information from factory robots or warehousing systems, these devices are networked too, so they can be attacked. You may have heard of StuxNet targeting centrifuge control systems. Yep, that’s what we’re talking about.
- Healthcare devices: If you go into any healthcare facility nowadays, monitoring devices and even some treatment devices are managed through network connections. There are jokes to be made about taking over shop floor robots and who cares. But if medical devices are attacked, the ramifications are significantly more severe.
- Connected home: Whether it’s a thermostat, security system, or home automation platform – the expectation is that you will manage it from wherever you are. That means a network connection and access to the Intertubes. What could possibly go wrong?
- Cars: Automobiles can now use either your smartphone connection or their own cellular link to connect to the Internet for traffic, music, news, and other services. They can transmit diagnostic information as well. All cool and shiny, but recent stunt hacking has proven a moving automobile can be attacked and controlled remotely. Again, what’s to worry?
There will be billions of devices connected to the Internet over the next few years. They all present attack surface. And you cannot fully know what is exploitable in your environment, because you don’t know about all your devices.
The industry wants to dump all these devices into a generic Internet of Things (IoT) bucket because IoT is the buzzword du jour. The latest Chicken Little poised to bring down the sky. It turns out the sky has already fallen – networks are already too vast to fully protect. The problem is getting worse by the day as pretty much anything with a chip in it gets networked. So instead of a manageable environment, you need to protect Everything Internet.
Anything with a network address can be attacked. Fortunately better fundamental architectures (especially for mobile devices) make it harder to compromise new devices than traditional PCs (whew!), but sophisticated attackers don’t seem to have trouble compromising any device they can reach. And that says nothing of devices whose vendors have paid little or no attention to security to date. Healthcare and control system vendors, we’re looking at you! They have porous defenses, if any, and once an attacker gains presence on the network, they have a bridgehead to work their way to their real targets.
In the Shadows
So what? You don’t even have medical devices or control systems – why would you care? The sad fact is that what you don’t see can hurt you. Your entire security program has been built to protect what you can see with traditional discovery and scanning technologies. The industry has maintained a very limited concept of what you should be looking for – largely because that’s all security scanners could see. The current state of affairs is you run scans every so often and see new devices emerge. You test them for configuration issues and vulnerabilities, and then you add those issues to the end of an endless list of things you’ll never have time to finish with.
Unfortunately visible devices are only a portion of the network-connected devices in your environment. There are hundreds if not thousands or more other devices you don’t know about on your network. You don’t scan them periodically, and you have no idea about their security posture. Each of thm can be attacked, and may provide an adversary a presence in your environment. Your attack surface is much larger than you thought.
These shadow devices are infrequently discussed, and rarely factored into discovery and protection programs. It’s a big Don’t Ask, Don’t Tell approach, which never seems to work out well in the end.
We haven’t yet published anything on IoT devices (or Everything Internet), but it’s time. Not because we currently see many attacks in the wild. But most organizations we talk to are unprepared for when an attack happens, so they will scramble – as usual. We have espoused a visibility, then control approach to security for over a decade. Now it’s time to get a handle on the visibility of all devices on your network, so when you need to, you will know what you have to control. And how to control it.
So our newest series, entitled “Shining a Light on Shadow Devices,” will focus on the risks these devices present to organizations, and how to find them within your environment. We’d like to thank ForeScout Technologies for tentatively agreeing to license the content and, as always, we’ll write this series using our Totally Transparent Research methodology. This ensures you’ll see all of the research as it comes off the assembly line, and you can keep us honest by letting us know if we’re hitting the mark.
Our next post will dig into how these device classes can be attacked.