Spoofing, Jamming, Chaff, and Flares

I promised this week I’d talk about spoofing, jamming, chaff, and flares. The military refers to these as countermeasures (CM). CM are devices or techniques used to cripple the effectiveness of enemy activities. They can include things that interfere with or mislead enemy communications, radars, and weapons systems.

Let’s talk about some early examples. The telegraph was first used during wartime in the United States during the Civil War. This first electronic technology was an important communications tool – and a tantalizing target. The Confederacy, which had fewer telegraphic resources, routinely rerouted Union telegraph traffic, transmitted false messages, and cut the wires of their northern opponents. Thus, the practice of disrupting and sending false information in electronic communications began in the US in the 1860’s. The sending of false information, disguised to look like a legitimate electronic message to mislead the opponent, came to be called (electronic) spoofing. See Alfred Price’s The History of US Electronic Warfare (volume 1) for more details.

Then wireless communications came along. The first electronic jamming during wartime was done by the Russians in 1904 against the Japanese. The Russian used electromagnetic (EM) energy in the radio frequencies to disrupt the communications among Japanese ships attacking Port Arthur (now Dalian, China).

Mastery and control of the electromagnetic spectrum (EMS) became a decisive issue during World War II. One side would use radar or communications at a specific frequency, and the other side would jam it with a signal at the same frequency. If one side moved to a new frequency, the opposition would develop a capability and jam that. And so began the never-ending cat-and-mouse game between the Allied and Axis powers. The Allies would win.

Specifically, the British used ground-based and airborne jammers against German radars and communications. British jammers like MANDREL, MOONSHINE,  and CARPET II reduced the effectiveness of German radars. They used other devices – like DARTBOARD, TINSEL, DRUMSTICK, and AIRBORNE CIGAR – to jam German HF and VHF communications.

The Brits also adapted spoofing techniques for the World War II battlefield which “brought chaos to the German night-fighter communications.” The same author also tells us that:

·      The Moonshine jammer amplified the radar return of the jamming aircraft and made it appear as big as a bomber formation to the early warning radars. The aircraft acted as part of a spoofing force to draw the Germans away from the real bombers.

·      Corona was a ground HF jammer used to broadcast false information to the German night fighters or attempt to tie up their communications channel.

If you are interested in more details, see https://apps.dtic.mil/dtic/tr/fulltext/u2/a215411.pdf.

Another significant CM used during the war was chaff. In the mid-1930’s, some British researchers looked at whether falling strips of metal foil or suspended lengths of wire could thwart enemy radars. The Americans would learn about this work in 1942 and contribute to the effort. The metal strips were designed to be a length of one half a wavelength of the enemy’s radar, just like antennas. Such a length could potentially flood the enemy’s radar system with a lot of confusing echoed signals. The Brits called this technology window; the US called it chaff. It is commonly known as chaff today. Since the advantage of a secret weapon is partly lost once it’s been used, the Brits held off using chaff until 1943.

Chaff belongs to a broad category of CMs known as decoys, which also include flares. The first CM flares were developed in the United States in the mid-1950’s, well after World War II was over.  Flares are designed to draw heat-seeking weapons away from their intended targets. Here’s a scenario. The enemy fires a missile, intending for it to track the target plane through its high thermal signature. The plane’s thermal signature occurs in the infrared (IR, 300 GHz to 400 THz) part of the spectrum. So the missile is tracking the plane in the IR, not at a radio frequency. As a CM, the pilot deploys pyrotechnic flares as decoys to lure the missile away from the plane. While the plane may have been detected by the enemy using radar frequencies, it’s being attacked and defending itself using the IR.

Jamming, spoofing, chaff, and flares are all still used today. OF course, the most sophisticated of these military technologies are hidden behind classified doors. However, many of these CM operate in a new environment and are talked about every day. We see old techniques like jamming, spoofing, chaff, and flares reappearing in cyberspace with names like distributed denial of service (DDOS) attacks, spoofing, firewalls, and honeypots. In both cases, it remains an ever-evolving game of deception and one-upmanship.

Come back next week, when we’ll talk scratch the surface of cyber defense and attack.