OPINION | Challenges for IoT based Wireless Devices in Physical Security Controls
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OPINION | Challenges for IoT based Wireless Devices in Physical Security Controls

By Nick Hunn

If you believe the futurologists, then the Internet of Things (IoT) is going to be the next big thing. Depending on who you listen to, by 2020 there will be up to 50 billion connected devices, an order of magnitude greater than the number of mobile phones. You can already see the start of that, whether it’s smart meters, connected information signs, or the increasing  number of fitness devices, like Samsung Gear, Apple Watch, Moto 360, Google Glass, Fitbit and Nike’s Fuel wristband. To get a better idea of what else may be emerging to make up that number, a good place to start is Kickstarter – the website for crowd-sourced funding for such projects.  It shows that a significant number of potential start-ups are looking for money to produce a bewildering array of gateways and sensors.

OPINION | Challenges for IoT based Wireless Security Measures in Physical Security Controls

The Concept of Physical Security Controls:

A range of physical controls can be implemented to help increase security. These controls are put in place to ensure that only authorized individuals can access certain areas or perform specific actions. Network cabling security should be considered when initially setting up wiring closets and whenever upgrades are performed. Cabling should be routed through the facility so that it cannot be tampered with. Unused network drops should be disabled and all cable access points should be secured, so that individuals cannot install sniffers or eavesdrop on network communications.

Another important concern is controlling individuals as they move throughout a facility. Most organizations use card keys, badges, smart cards, or other IDs to control the flow of traffic. This category can be divided into two broad groups. The first category is ID cards, which do not contain electronics and are very low tech. ID cards typically contain a photograph of an individual to verify their identity, and are used in many organizations.

The second category is intelligent access control devices that make access decisions electronically. There are two subcategories of these devices: contact and contactless.

Contact access cards require users to slide their card through a reader. These cards come in several different con-figurations, including:
  • Active Electronic - Can transmit electronic data
  • Electronic Circuit - Has an electronic circuit embedded
  • Magnetic Stripe -Contains rows of copper strips
  • Optical-coded - Contains laser-burned pattern of encoded dots.

Contact-less cards function by proximity (e.g., radio frequency ID [RFID]). An RFID is a small electronic device comprised of a microchip and an antenna. An RFID tag can be designed as an active device (i.e., a battery or power source is used to power the microchip) or as a passive device - Passive devices have no battery; they are powered by a RFID reader. The reader generates an electromagnetic wave that induces a current in the RFID tag. There are also semi-passive devices that use batteries to power the microchip, but transmit using the energy from the card reader. When users are allowed into specific areas of a facility, it does not mean that they should have access to all of the systems located there. That’s why strong system access controls are so important. Complex passwords or biometric systems can help, as well as multi-factor authentication (e.g., ATM bank cards). Banks require you to have an ATM card and a pin number in order to access funds or account information.

Even with these physical controls in place, misuse and intrusions can still occur; therefore, it is important to use IDSes. Physical intrusion detection includes the components and systems installed to detect misuse or unauthorized intrusion. Physical IDSes are designed around one or more sensor types. Motion detectors can be triggered from audio, infrared wave pattern, or capacitance. These detectors use passive infrared and are usually mounted in the corners of rooms or used as security lights. Motion detectors send out a series of infrared beams that cover an area with protection.

Other types of sensors used with IDSes include photoelectric sensors and pressure-sensitive devices. Pressure sensitive devices are sensitive to weight. They measure changes in resistance to trigger alerts, and are good for protecting small areas. Glass breakage sensors are another component of IDSes. If someone breaks a window or attempts to pry it open, the sensor triggers an alarm. IDSes are another piece of total security control. The idea is to place them in key areas that contain critical assets or in areas most likely to be violated by intruders. IDSes are not perfect and produce their own share of false positives. Every time an alarm goes off, someone must respond and verify the event. If IDS is tied to a police department or fire department, false alarms can result in some hefty fines.

The Evolving Concept of IoT with respect to Wireless Security Ecosystem

The rise of these connected devices, which is the vanguard of the Internet of Things, is really exciting.  But it’s mostly happening with low cost, proprietary wireless chips.  The growth of products from new start-ups and Kickstarter projects are being fuelled by silicon vendors who are bringing highly integrated wireless processor chips to the market.  The tools that support these chips and reference designs make it very easy to get prototypes up and running and then take the resulting products to market.  They’re wonderful devices to design with, but they generally leave any security implementation to the designer.  And wireless security is difficult.  So where does an IoT designer start?

Image Attribute: IoT Workflow / Source: www.nickhunn.com

Image Attribute: IoT Workflow / Source: www.nickhunn.com

Most wireless sensor systems can be broken down into three distinct parts – the sensor, which generates the data; the gateway (which may be a mobile phone) that takes sensor data and transmits it over the Wide Area Network (WAN) and the server/database which receives, stores and processes it.  The traffic (at a high level) may be bidirectional, with control signals going back down to the sensor.  And the WAN access may be an integral part of the sensor, as is the case where it contains a cellular modem.  But in most cases it’s not.

Where it is separate, there are typically two wireless links – the short range, local or personal area network and the wide area connection, which is generally either cellular or broadband.  The chances are that any security implementation is different over both, and that there’s not any end-to-end security.  Most systems tend to be put together in a piecemeal “Lego” fashion, so security is at best only link wide.  There are some vocal advocates of IP to the device, claiming that it plays to the end-to-end security model, but I’m still to be convinced that IP and low power wireless make sensible bedfellows. Which means that most real Machine-2-Machine (M2M) and IoT implementations are likely to combine a number of different security schemes, without an overall end-to-end security model?

If security is important to you then one of the first things you need to do is to construct an end-to-end security model.  Even if you think that it’s not important for your application, it’s still worth doing this, so that you can demonstrate why you didn't need to implement it.  The principle here is that you need to think through what you are trying to protect and what the consequences of an attack may be. The severity of risk may not be where you think it is.  Too often we have seen massive overkill in a sensor or gateway which then places secure data from multiple sources in an unsecured server.

It is to be noted, how important it is to do this at an early stage of the design process, as it affects the choice of protocols and chips.  When it’s done early on, it adds little cost or time to a project.  Adding it as an afterthought can cripple the cost of a product or service, or at worst send it back to the drawing board.  

The Concept of RMADS - Risk Management and Accreditation Document Set

As soon as you have decided what you want your product to do, and sketched out the overall architecture, sit down and produce what the industry calls an RMADS. The philosophy behind it is to ask what are the consequences of data being lost, corrupted or injected at each stage.  Each of these three possibilities is important to consider.  And their relative importance will be different for different applications.

Common sense here really means thinking about fit for purpose.  For many sensors around the home it may not matter if they can be overheard.  It may matter more if someone can inject spurious packets, as that can lead to false alarms, the transmission of incorrect data that gets back to the server or the annoyance of something being turned on or off.  All of which can reduce customer confidence in your product as it makes it look unreliable.   An associated point to consider is working out how to add new wireless devices to the network and stop rogue ones being attached.  Pairing and authentication is one of the most difficult aspects of wireless, as ease of use and security comes head to head. You also need to think about how to swap out defective devices without leaving vulnerabilities, which essentially means working out how to distribute link keys securely around your system.

At the gateway you need to consider how you ensure that the sensor data gets back to the server securely.  This generally means TLS, unless you have end to end security.  That’s not the way most IoT devices work today, as the community is promoting simplicity, open hardware, open APIs and simple POST messages.  That doesn’t means you can’t design secure open systems, but you need to understand what level of security you’re being offered and make sure you’re happy with it.  Once again, it’s about understanding what you’re implementing and whether it meets your needs.  Remember that in most cases, commercial IoT products are only viable when the customer can trust the way their data is being handled.  That’s a very different scenario from people experimenting with Arduinos and open sensor projects.  Each have their place, and can extend into each other’s, but the inherent security levels of each should not be confused.

Often the biggest issue is at the server, where a lack of thought can expose the data.  As we regularly see, even large companies who should know better don’t handle their passwords and authentication robustly.  And the bigger the target, the more interesting it gets to hackers.  If you’re designing a commercial system and you’re lucky, it could catch the zeitgeist and grow beyond your wildest dreams to become a significant part of those 50 billion devices.  Some of the products being designed today are probably destined to do that.  At which point any lack of security in their initial design will come back to haunt them and their investors, which is another reason for getting it right at the beginning.

About The Author:

Nick Hunn, Technology evangelist, serial entrepreneur and developer with a broad view of both the detail of technologies, the user experience and wider interplay of different market solutions. Leading edge technology analysis, development and evangelism. Speaker and conference chair within the wireless, smart energy, eHealth, wearables, IoT, telematics and Big Data areas and author of numerous white papers. He blogs at www.nickhunn.com

This article is an abridged from a paper written by the author in year 2012 under the title – “Wireless Security for the Internet of Things”. 
This work is licensed under a Creative Commons License.