If you're doing latency-based probing, location spoofing is presumably possible to an extent by adding artificial delays and possibly spoofing ICMP "TTL expired" packets like https://github.com/blechschmidt/fakeroute

I am not sure whether this kind of IP spoofing will impact our accuracy because we will likely identify the noise and behavioral anomaly and discard the location hint derived from traceroute.

We have tons of historical traceroute data patterns, and generic traceroute behaviors are likely modeled out internally. So, if you can spoof the traceroute to your IP address, our traceroute-based location hint scoring weight for that IP address will decrease, and we will rely on the other location hints.

You have to be extremely deliberate to misguide us. But I would love to see this in action, though.

Yeah, I doubt there are more than a couple of hosts on the entire internet serving fake traceroutes anyway. Even finding hosts that don't enforce BCP38 requires quite some effort these days.

I don't think it is fair to IPInfo to give the specifics publicly, because once you have the "ah ha" moment you realize it is an entire class of difficult to address problems with how they use their sensor network. That knowledge only helps the bad guys.

We are actively trying to improve our system and build it as figuratively 'antifragile'. We can not afford to get comfortable and we need to constantly find faults in it. If you know anything, you can contact our founder or me directly.

The problem is that everyone knows we are the most accurate data provider and our growth is exponential. To my knowledge, most cybersecurity teams use our data to some degree. We cannot risk having any secrets out there that could disrupt the accuracy of the system. We are aware of several cases where accuracy may be affected, with the most notable being adversarial geofeed submissions.

If the issue is an adversarial geofeed submission, it is a well-known problem. When active measurement fails, we have to fallback to some location hint. There are layers of location hints we have to fall through to ultimately landing on echoing geofeed location hint.

But aside from that... I'm not sure what could possibly impact us. A substantial systemic malicious change in data accuracy seems highly unlikely and quite impossible.

Why do we assume that only "bad guys" would want to bypass internet censorship?