alt Hacker NewsMullvad exit IPs are surprisingly identifying
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> As an example, imagine that you are a moderator on a forum and you suspect that a new face is actually a sockpuppet of a user you banned the day prior. You check the IP logs, and despite using different Mullvad servers, both accounts resolve to the overlapping float ranges 0.4334 - 0.4428 and 0.4358 - 0.4423. This gives you a >99% chance that they are the same person.
I don't see how the author is arriving at this ">99% chance" purely from the numbers provided in the article. Assuming the first (banned IP) seed and the second seed are both in the range 0.4423 - 0.4358 (a stronger assumption than is justified by the example), all this tells us is that the first and second IP addresses both have seeds in a range that would contain 0.4423 - 0.4358 = 0.65% of all Mullvad users, which 0.0065 * 100,000 = 650 users. We've eliminated >99% of users as "suspects", but we haven't actually gotten >99% accuracy in identifying an individual across multiple exit IPs.
In more Bayesian thinking, the overlap in potential seeds is great evidence to think these IP addresses represent one and the same person (or Mullvad VPN account at least), but as far as I can tell, that's not what the author is saying.
The purpose of a VPN does not include anonymizing users with respect to the sites they visit,so it shouldn't be too surprising that Mullvad doesn't enforce unique exit IPs. Users who want anonymity should use networks like Tor.
> Surprisingly, the exit IP you are given is not randomized each time you connect to the server, but deterministically picked based on your WireGuard key, which rotates every 1 to 30 days (unless you use a third-party client, in which case it never rotates).
I'm a little confused on this... what is stopping third parties from doing key rotations like the main app clients if it is detailed in the repo how to do it?
It seems surprising that people would expect a VPN to be comparable to Tor.
It does seem ridiculous once you spell it out like that, and then you have to realize that it’s plausible to de-anonymize even Tor users by controlling exit nodes.
We keep adding layers of encryption and the metadata keeps snitching on us anyway.
Given that Mullvad is basically a bulletproof VPN host[1], it would be great if site operators could rely on this property to enact bans. Given that the solution is simple (add a pseudorandom seed), Mullvad will likely push out a fix within a couple days.
1. It's the preferred VPN of TeamPCP.
I maintain a list of
"23034 IPs to blocklist.txt"
blocked IPs they contain all VPN providers. Often VPN providers seed Geofeeds with wrong data, this is why i use traceroute and ping network to locate their real location.
It's a game of cat and mouse. The service keeps banning IP ranges, the user keeps reconnecting to different servers and regions. The server can't know exactly who's who, just that a bunch of users are using mullvad, while the user just need to find one server on one IP range that works.
Seems like a good deal to me. I don't care if they know I use mullvad, I care they don't know I'm me, and that's not something mullvad will easily disclose.
surprising that the mapping may be stable enough to become a user-level signal. and rotating away from deterministic assignment seems like a cheap way to avoid creating an extra fingerprint
>Surprisingly, the exit IP you are given is not randomized each time you connect to the server, but deterministically picked based on your WireGuard key
What's the point of this? This seems more complicated to implement than mapping exit ips at the server level, so surely they must be doing this for a good reason?
Reusing the same VPN between multiple identities is a horrible idea regardless. And let's be real. As a forum moderator if you ban a Mullvad user and then a new Mullvad user signs up the next day it is probably the same person. You should be using residential or mobile proxies if you want privacy and to blend in to everyone else.
This is why VPNs have always been crap. The pool of IPs are backlisted/tainted, so you will run into various roadblocks and cpatchas, in addition to slow speed. If you are serious about privacy and don't want blocks and blacklists, buy high speed private proxies. Don't use a pooled service.
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> As an example, imagine that you are a moderator on a forum and you suspect that a new face is actually a sockpuppet of a user you banned the day prior. You check the IP logs, and despite using different Mullvad servers, both accounts resolve to the overlapping float ranges 0.4334 - 0.4428 and 0.4358 - 0.4423. This gives you a >99% chance that they are the same person.
This sounds like how I'd design a VPN if I were an intelligence agency.