Mullvad exit IPs are surprisingly identifying

(tmctmt.com)

118 points | by RGBCube 1 hour ago

10 comments

  • solenoid0937 11 minutes ago
    > 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.

  • gchamonlive 5 minutes ago
    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.

  • lorenzohess 30 minutes ago
    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.
  • VoidWhisperer 30 minutes ago
    > 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?

    • nvme0n1p1 11 minutes ago
      Third party clients include e.g. the WireGuard driver in the Linux kernel. It's definitely not the network driver's job to mitigate an attack against one specific commercial service.
  • linkregister 47 minutes ago
    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.

  • Riany 12 minutes ago
    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
  • gruez 59 minutes ago
    >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?

    • arciini 56 minutes ago
      I'd guess that this is to ensure one abusive user doesn't get every other user blocked from a large service (say, Google) for botting over the VPN and constantly rotating IPs.

      It's a practical measure, but definitely has a privacy cost though.

      • stevekemp 50 minutes ago
        It's possible that contributes, but to be honest most VPN users are split "privacy seeking" and "abusive". Though I grant you paid users are probably slightly more circumspect than users of Tor, etc.

        It seems more likely this is just about load-balancing use against their available nodes.

    • TheDong 16 minutes ago
      It's a lot easier to implement because it's more stateless, and it's a better user experience.

      If you get a new exit IP each time you connect, you need something like a NAT table to look up "key 0xabc exits ip 1.2.3.4", and that grows to be the size of the number of users you have active, so fairly large.

      With a static mapping derived from the key, you don't need a table like that.

      It's also better UX since it means reconnecting your VPN software (say you switch wifi hotspots) doesn't give you a different IP address, so things like SSH sessions can resume, which wouldn't be possible if it were a different public IP each time.

    • Riany 9 minutes ago
      My guess is deterministic assignment makes load distribution and debugging easier. But for a privacy product, that convenience probably needs to be reconsidered
    • tempest_ 55 minutes ago
      I imagine there are a bunch of things on the internet that break if you start trying to connect to them from varying IP addresses. Things like the various CAPTCHA schemes and rate limiting etc, IP reputation etc.
      • lmm 39 minutes ago
        > I imagine there are a bunch of things on the internet that break if you start trying to connect to them from varying IP addresses. Things like the various CAPTCHA schemes and rate limiting etc, IP reputation etc.

        Given how much of the world is stuck behind CGNAT now, I would expect any major sites to handle it.

  • JoheyDev888 47 minutes ago
    [flagged]
    • malfist 4 minutes ago
      Let's see, short summary of the article, saying nothing new or important. It's not x it's y. Comment history is exactly this type of comment everywhere.

      This is an AI comment from an AI account.

    • GalaxyNova 39 minutes ago
      Doesn't matter much as long as it is a pseudonymous identity
      • stingraycharles 31 minutes ago
        It’s also not that difficult to fix, so I expect a fix to roll out soon enough.
  • wg0 56 minutes ago
    VPNs are snake oil. Exit IPs are a public information.
    • Cider9986 50 minutes ago
      VPNs are not snake oil. They transfer the trust of your internet activity from a place of low-trust, your ISP, to a place of high-trust, ideally a trustworthy VPN like Mullvad, IVPN, or Proton. Among other benefits. If you don't like your ISP creating a profile of you and selling it to target ads to you, you should use a VPN.

      >Should I use a VPN?

      Yes, almost certainly. A VPN has many advantages, including:

      1. Hiding your traffic from only your Internet Service Provider.

      2. Hiding your downloads (such as torrents) from your ISP and anti-piracy organizations.

      3. Hiding your IP from third-party websites and services, helping you blend in and preventing IP based tracking.

      4. Allowing you to bypass geo-restrictions on certain content.

      (https://www.privacyguides.org/en/basics/vpn-overview/)

      • wg0 8 minutes ago
        How is private company (VPN) is more trustworthy than an other private company (ISP) and how do you expect them to protect your identity in face of determined state actors that are afer you?

        What power is in $2.99/month that it offers so much security?

        Why is that at least 40% of sponsorship to YouTube Creators seem to be from VPN industry?

        What is that they know and we don't know?

      • bilalq 41 minutes ago
        Unfortunately, the largest and most well-marketed VPNs are, in fact, less trustworthy than your average ISP.
        • SXX 19 minutes ago
          This depends on your treat model. If what you worry about is massive collection of Linux ISOs that you download and distribute over P2P then probably shady VPN ISP is what you need.
        • asdfsa32 30 minutes ago
          Exactly. Most ISP are subject to local laws at least; where a lot of these ISP are overseas in shady jurisdictions.
      • jesterson 43 minutes ago
        > place of low-trust, your ISP, to a place of high-trust, ideally a trustworthy VPN like Mullvad

        This is highly subjective statement.

        Almost all commercial VPN services farm and sell your data. Just by that, my ISP is definitely high trust point while any commercial VPN is a low trust.

        • applfanboysbgon 35 minutes ago
          Your ISP farms and sells your data too.

          Most VPNs are untrustworthy, but unlike ISPs, you can choose from any VPN provider in the world, not just the two or three that are local to you. And there are VPN providers in the world that have been proven not to retain data by audits + actual court cases where the court determined that the VPN provider did not have the data authorities were seeking. Do your research and choose a court-proven VPN, it's that simple.

          • KingOfCoders 7 minutes ago
            Deutsche Telekom in Germany/EU farms and sells my data? Any sources?
        • faangguyindia 9 minutes ago
          Most ISPs have invested big bucks in Deep Packet Inspection
        • sfdlkj3jk342a 36 minutes ago
          I can easily pay for a VPN service with crypto anonymously. I can also use a VPN run by a company outside my country of residence and jurisdiction.

          Neither of those is possible with my ISP.

          • dakolli 22 minutes ago
            prepaid 5g sim cards and 5g modem.
            • SXX 13 minutes ago
              Yes and 5G provider knows your exact location while VPNs can be easily chained.
        • jojobas 29 minutes ago
          Now try saying that wearing some Russian or Chinese shoes.
    • Cider9986 38 minutes ago
      I was just talking to a friend who believes that the feds poison privacy communities by spewing nonsense like this. I don't think wg0 is a fed, and my friend didn't have any proof for his claim. My feeling is that it is probably people acting like regular humans. They hear things, they have opinions and they don't provide proof or adhere to community norms. Eternal september or something. Regardless of if it's federal agents disrupting the discussion or human nature, the response should be the same—push back with proof, and demand proof and avoiding logical fallacies.

      >Also. This is how they ruined any meaningful talks about privacy

      There is so much noise

      "Use braive. Don't use braive. Use vpn. Don't use vpn"

      Then the debate spreads to all other aspects password managers, emails and etc

      • kalium-xyz 7 minutes ago
        If people using some tool made my job harder id be vocally against it during off hours. But lets be real any powerful group interested in tracking people would just be working with or running vpn companies. Or perhaps providing free vpn. Either way I think its all moot as for tracking you have to question who you do and do not want to be tracked by and for other purposes vpn works just fine
    • dewey 47 minutes ago
      > VPNs are snake oil

      The most generous way of reading that would be the fact that every YouTube pushing for a VPN as an essential tool just to use the internet outside of your house without getting hacked is a big exaggeration or fear mongering but there's good reasons for using a VPN for a lot of reasons and it's not snake oil.

    • avazhi 52 minutes ago
      > Exit IPs are a public information.

      Yes, obviously.

      > VPNs are snake oil

      Huh?