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Comment by punnerud | Hacker News Reader

This is a weakness in the Wi-Fi stack, I can't see than he have interfered with the signal it self. It is the router and/or the client that have picket up these signals and misinterpreted them (though they were targeted). The rule they mean he have broken: ###"harmful interference” as “[a]ny emission, radiation or induction that endangers the functioning of a radio navigation service or other safety services or seriously degrades, obstructs or repeatedly interrupts a radio communications service operating in accordance with this chapter.###

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I think this is the exception that swallows the rule.

Let's say I observe two ham radio operators having a morse code communication. I decide to stop them from communicating, so I transmit "<callsign 1> QRT DE <callsign 2>", where callsign 1 and callsign 2 are the callsigns of the two ham radio operators.

Is this harmful interference, or did one of the ham radio operators just misinterpret my signal?

I wouldn't trust the "<callsign 1> QRT DE <callsign 2>" if it didn't contain a secret message, that couldn't be produced by a 3. party

Well, I think then you'd be breaking protocol, because afaik, in ham code you must obey procedure, and QRT tells you to stop transmitting.

In Ham radio, you can't use any sort of secret message like that. Everything needs to be plaintext.

I don't think that's correct. Cryptographic authentication of messages should be allowed (ARRL agrees with me[0]), the language specifies you cannot "obscure the meaning" of the communication.

0. https://ecfsapi.fcc.gov/file/7520928844.pdf

That's correct. There's one exception to the encryption rule, which is when sending commands to a space station. (That does not allow you to encrypt the responses, though.) See 47 CFR 97.211, https://www.law.cornell.edu/cfr/text/47/97.211

  I decide to stop them from communicating, so I transmit "<callsign 1> QRT DE <callsign 2>"
  Is this harmful interference?

On amateur radio, you're obliged to identify yourself, so this would be a breach of licence: failing to identify your station, or misrepresenting your station.

True. But let's say that didn't apply. Would this be harmful interference?

Let's suppose that the Earth is flat... :)

> It is the router and/or the client that have picket up these signals and misinterpreted them

From what I understand of this attack, the signals are not being misinterpreted. The client receives a packet which basically says "I'm the AP and want you to disconnect", so the client correctly does what the packet asks it to. The packet, however, was spoofed; who send it was not the AP, but someone else.

The solution to this particular attack, as someone else mentioned, is 802.11w, which authenticates these control packets so they can't be spoofed. Unfortunately, it's still uncommon.

It's pretty straightforward: sending fake deauth packets “seriously degrades, obstructs or repeatedly interrupts a radio communications service”.

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