Think about the last time you communicated via radio. Many people think they only listen to the radio in the car or think about the time when Morse code, walkie-talkies and teletype machines were more prevalent. But the truth is, mobile phones, hot spots, baby monitors and other wireless technologies all use radio waves to communicate, and any communication device that uses radio waves to communicate is a radio.
Radio waves move at different rates called radio frequency (RF). The RF spectrum is a wide range of the electromagnetic spectrum that ranges from 30 hertz (Hz) to 300 gigahertz (GHz). The higher the RF, the faster the data rate, assuming that compression and modulation are constant. Radio waves have 2 parts: the carrier, or base frequency that is being transmitted, and the data that are modulated onto the carrier. The data part can be applied to the carrier as analog or digital. The strength of the carrier determines how far the data can be transmitted and received in a usable state.
To prevent radio signals from drowning each other out, there is, in the United States for example, a Table of Frequency Allocations maintained by the US Federal Communications Commission (FCC) and other various organizations. The Table of Frequency Allocations is divided into bands of contiguous frequencies. These allocated bands are designated for cell phones, radars, remote control, television, AM/FM radio, etc.
As cybersecurity professionals, we need to understand the wireless environment and the impact of these types of communications on our security posture. Following are some misunderstandings of RF-based communications that apply to the electromagnetic spectrum:
- Encryption makes the RF signal invisible and prevents it from being intercepted—This is untrue because encryption protects data prior to modulating them onto the RF carrier. The radio waves, both the carrier and the modulated data, can be intercepted, but the data are protected. There are techniques that can be used to prevent signal interception, but generally speaking, if you are properly located and listening to the right frequency, you can intercept all RF communication.
- RF signals carrying digital data go further than RF signals with analog data—This is false. The strength of the signal, the environmental conditions, atmosphere and terrain determine how far an RF signal can travel and still be usable at the receiving end.
- More Wi-Fi hotspots are better—This statement is mostly false. If members of your C-suite travel, each member should have a personal hotspot so they do not accidentally connect to a hostile hotspot, but this is not because more hotspots are better. A hotspot has 2 sides. There is a cell radio that connects to your Internet service provider (ISP), and there is a Wi-Fi radio that allows up to 4 or 5 users to connect. However, if you put more than 4 hotspots into a single room, strange things occur. While the cell side of the hotspot is fine, the Wi-Fi side experiences issues. Because Wi-Fi all works on the same frequency band, the signals begin to drown one another out. This is called jamming or stepping on one another. Even though you have plenty of cellular signal strength, the Wi-Fi signals are in conflict and no one can connect consistently.
- Radio waves continue on into space forever—This is not really true. Radio waves are like dropping a pebble into a pond. As the ripples move away from the impact point, they get weaker and weaker until they reach a point where the RF signal-to-noise ratio makes the signal unusable.
Wireless technology is growing faster than wired communication. The next generation of cellular, 5G, will offer data rates reaching 9 gigabytes (GB). In addition, the introduction of software-defined radios (SDRs) will make radios RF agile. RF agility means that any given radio can work on any frequency in the RF frequency spectrum. This means the same people who hack systems today could soon violate the Table of Frequency Allocations if unchecked. It is a fun time to be in wireless technology development.
Bruce R. Wilkins, CISA, CRISC, CISM, CGEIT, CISSP, is the chief executive officer of TWM Associates Inc. In this capacity, Wilkins provides his customers with secure engineering solutions for innovative technology and cost-reducing approaches to existing security programs.