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Comment by WASDx | Hacker News Reader

Hide a GPS spoofer (illegal) at a central train station to make all trains believe they are at the forbidden workshop location and make them brick themselves? Could it be that easy?

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Is there such thing as GPS spoofer? I would guess only JAMMER is possible.

Yes[1], and is a regular occurrence.[2] It was also the method by which Iran stole a US drone.[3]

[1]: https://en.wikipedia.org/wiki/Spoofing_attack#GNSS_spoofing

[2]: https://www.ainonline.com/aviation-news/air-transport/2023-0...

[3]: https://en.wikipedia.org/wiki/Iran%E2%80%93U.S._RQ-170_incid...

You can buy this bad boy and hook it up to a software defined radio and it will spoof away!

https://safran-navigation-timing.com/product/skydel-simulati...

GPS C/A signals are pretty straightforward to generate and not authenticated.

You can spoof GPS. It just needs be in the sky, and JAM at the same time. In theory it is possible?

> It just needs be in the sky

The target doesn't need to be airborne for such an attack to work.

>A "proof-of-concept" attack was successfully performed in June 2013, when the luxury yacht White Rose of Drachs was misdirected with spoofed GPS signals by a group of aerospace engineering students from the Cockrell School of Engineering at the University of Texas in Austin.

https://en.wikipedia.org/wiki/Spoofing_attack#GNSS_spoofing

> The target doesn't need to be airborne for such an attack to work.

I mean, the spoofing signal needs to usually come from sky. You want to hinder the original signal and makes yours stronger. Of course, signal can be reflected and there are other means to reach this.

Can you elaborate on why you think that "the spoofing signal needs to usually come from sky"? As far as I understand, it literally never comes from the sky, in every single case it involved ground-based transmitters.

The GPS system doesn't use the direction to the GPS satellite for localization but rather only the distance i.e. timing, so spoofing GPS is based on accurate control of the time of the transmitted (or replayed!) signals.

> The GPS system doesn't use the direction to the GPS satellite for localization but rather only the distance i.e. timing, so spoofing GPS is based on accurate control of the time of the transmitted (or replayed!) signals

GPS uses Signal-to-Noise ratio for determinating the signal quality and integrity. Horizontal signal will suffer pretty fast. Especially if your receiver is sophisticated and could actually detect the signal strength (power) outliers. If you want to spoof GPS signal very well, it should be also weak. But weak signal will quickly disappear with ground-based transmitters.

I used ”strength” incorrectly on the previous comment.

GPS spoofing is generally done at limited range and line of sight so the fact that "horizontal signal will suffer pretty fast" and having the range limited by terrain and curvature of the earth is not a problem but a feature that the spoofers generally want - affecting the target, but not affecting people 500 miles away; and sometimes even explicitly doing that from a pit so that spoofing or jamming affects airborne targets but not those on the ground.

And regarding "If you want to spoof GPS signal very well, it should be also weak" the scenarios I've seen (e.g. targeting drones in current conflicts) often explicitly target non-sophisticated commercial off-shelf GPS modules that don't attempt to detect spoofing and will gladly accept a signal that's 100 times louder than the actual satellites, so I think the spoofers often have no desire to do it "well" according to your criteria.

I would imagine it only works while trying to service the train (or at least while the train thinks it's being serviced).

It only bricks if they're there 10 days.

Hide a spoofer on the train itself, this way you can target any train anywhere

Yeah, trains tend to have large cabinets inside, and not like those cabinets are opened and inspected every day.

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