Wednesday, October 14, 2015

Jamming WiFi is pretty easy, it seems

Inexpensive, too:
A security researcher has demonstrated that jamming WiFi, Bluetooth, and Zigbee networks is not difficult to perform but, most importantly, also not as costly as one might think. 

According to Mathy Vanhoef, a PhD student at KU Leuven (Belgium), it can easily be done by using a Wi-Fi $15 dongle bought off Amazon, a Raspberry Pi board, and an amplifier that will broaden the range of the attack to some 120 meters.

The attack would hit all devices within range that operate in the 2.4 and 5 Ghz bands.
In my security nerd heart of hearts, I want frequency hopping WiFi.  But you'd need a wider band of frequency than the FCC would give up.

Damn Fed.Gov, bogarting all the frequencies ...

2 comments:

drjim said...

One of the original 802.11 WiFi standards was for frequency hopping.

I still have some PC cards that do that, but they don't transfer data nearly as fast as the more "modern" standards do.

Tony Tsquared said...

For frequency hopping WiFi A time devision multiplexer (TDMA) with an adjustable bandwidth is what you need. They make those in the 12-18 GHz range for satellite transceivers.

The 802.11 protocol has WiFi in 5 distinct frequencies in the 2.4 GHz, 3.6 GHz, 4.9 GHz, 5 GHz, and 5.9 GHz bands. Each of the bands contain overlapping channels of 22 MHz each. To get a TDMA operational you would need a transceiver that could communicate in two or more of the frequencies and you would need to have minimal overlap (some would be required).

The problem is the typical TDMA modem smallest footprint is a rack mount 1 ru modem ($15K) that cost about 3 times what the 2 ru unit runs ($5k). If you were able to get the frequency reprogrammed at the lowest power setting you would be broadcasting 30 miles if you had an omni directional antennae. A directional antennae would go further. This would also interrupt all other off-the-shelf wireless networks within its range. The current system is not designed to have channel sharing and that is part of the reason the ranges are fairly limited. The FCC would go crazy if someone put one of these together and used it.