How to Make Your Wireless Data System More Resilient to Attack

• By Matthias van Doorn
• Aug 23, 2010

Automation and data communication networks have enabled the integration of critical infrastructure into cyberspace. Now, computer networks and data exchange are responsible for keeping our water supply clean, heating and cooling our homes and businesses, and even keeping people safe and secure.

The virtual environment further offers convenience and opportunities for cost savings. For example, we can review and pay our electric bills online, rather than writing a check and mailing it to the utility through the U.S. Postal Service. Similarly, cyberspace will reshape our behavior when the Smart Grid comes online. Technology already promises access to data showing real-time energy consumption and cost, giving us the opportunity to lower those bills.

But what makes cyberspace attractive to us also makes it vulnerable to exploitation by others.
The seriousness of this threat has been acknowledged by the Pentagon and the Department of Homeland Security. New policies and security standards, such as the Cybersecurity Enhancement Act of 2010 (pdf) and a grant for energy delivery systems to the National Electric Sector Cyber Security Organization, are being developed and funded.

The most common threats to data communication networks are Denial of Service (DoS) and Intrusion.

DoS is an attempt to make a computer resource or network unavailable to its intended users. This attack could be as simple as jamming an electric or electromagnetic signal or as sophisticated as saturating a system or network with communication and data traffic so that legitimate data does not get through and is not processed. These attacks can be irritating (when service is unavailable or slow to respond) or dire (when critical control signals don’t reach their destinations).

Intrusion requires a different level of sophistication For instance, command and control attacks, packet spoofing, hijacking of sessions, replay attacks, the use of worms, Trojans and remote controllable Trojans are examples of sophisticated intrusion tools. Consequences can range from spying or stealing information to corrupting data or maliciously and intentionally causing harm or destruction by taking over network and/or computers and control systems.

Good wireless only better
Wireless data communication is based on electromagnetic waves using radio frequencies propagating through the air. This gives wireless some unique advantages, as communication endpoints don’t need to be tied to a fixed location or depend on a cable. In addition, running cable, conduit or even digging trenches between communication endpoints can be a time consuming, expensive and sometimes dangerous.

The flexibility of wireless data communication comes at a price. Electromagnetic waves are non-discriminatory when it comes to access. While a wired connection requires physical access to the cable, wireless connections can be made anywhere along the path on which the electromagnetic waves propagate. You probably have heard the story of a suspect in a parking lot who hacked into a private Wi-Fi connection to gain access to credit card or bank information. That is why security (as in secure access) becomes more important for wireless data communication.

The Frequency Hopping Spread Spectrum (FHSS) system is a type of wireless communication that is resilient to interference and “jamming.” Coordinated, rapid changes in radio frequencies literally “hop” in the radio spectrum, thus evading detection and the potential of interference. Other effects can be observed when wireless signals travel through space, such as the “multipath” phenomenon, simply because they use only very small amounts of radio spectrum at a time and don’t remain at that frequency for long.

FHSS makes DoS attacks very difficult, if not completely impossible. However, a resilient wireless system needs more than a rugged transmission system; it needs some type of access control but with authentication and authorization security levels of clearance.

Industry standard -based wireless devices have many positive attributes. However, one drawback is that these devices are only required to connect through an off-the-shelf standards-based device ─ compatible with those used in a specific wireless network ─ for access. Proprietary systems and devices (especially when they offer many “knobs” and configuration options to create more private networks) actually offer a higher degree of security. But even those devices can be acquired, if you know where to get them. For all these reasons, access control is one of the most important security features that can prevent unauthorized access and intrusion.

Access control should allow network access only by authorized devices and disallow access to all others. Access should be authorized and provided only to devices whose identity has been established (authenticated) and whose placement on the network is approved in accordance with network plans, designs, or policy. Remote Authentication Dial In User Service (RADIUS) is a popular method to provide centralized Authentication, Authorization and Accounting to manage wireless network access.

A good network security strategy should go even further and protect data “in transit” as well. Even if an unauthorized device manages to gain access to the network, it doesn’t necessarily gain access to the actual data without passing yet another layer of security.

Methods of encryption and deciphering have come a long way since their beginning. Today, the Advanced Encryption Standard (pdf) is the industry standard for encryption. No wonder, considering that its roots go back to the National Institute for Standards and Testing (NIST) acting on the need for a new encryption algorithm capable of protecting top secret information.

Other tools that can help “harden” a wireless data communication network may include policies to limit permitted activities to the minimum required for business purposes, such as User Level Access and Filtering (MAC addresses or IP packets). Often, convenience is the reason behind opening Firewalls, giving users too many privileges and too much access, or, even worse, using default settings and passwords that render other protective measures useless. This presents a major cyber vulnerability and an imminent threat to critical infrastructure where disruptions could result in catastrophic damage up to loss of life and property.

Any chain is only as strong as its weakest link. If we don’t start building and properly implementing adequate protections for our wireless data communication networks, (especially for our critical infrastructure, with the goal of making them more resilient) malicious hackers will keep exploiting, attacking and ultimately destroying our way of life.