This sounds like how I'd design a VPN if I were an intelligence agency.
I recall a PRISM slide showing the diagram of Google and the public internet, with a big arrow on GFE saying, quote, “SSL added and removed here! :-)”
If NSA aren’t installed at Cloudflare, I wonder what they are even doing.
Anyone with a few crypto currencies in their wallet that can click a button on any of the booter services with botnets for hire.
The funny thing about that era is you knew they started using Cloudflare because they went from stable with constant uptime to going down and showing a Cloudflare banner randomly all the time for a good year or so. They ran worse with Cloudflare than they did while they were allegedly getting DDoSed. The whole company glows, as the late great HN commenter Terry Davis would've said.
This is a massive issue in my view, it allows correlation across multiple VPNs exit nodes, but that’s it. It doesn’t allow to identify you automatically. It does significantly lower the bars for identifying you though, but the requirements are still high.
Hopefully they fix this soon.
I can’t believe this type of “let’s make it a hash or something sensitive” still happen, and at mullvad, of all places. Why not randomise it simply?
If you squint a bit, it looks a lot like a "Nobody But US" (NOBUS[1]) scheme. A few more identifying bits could tip the scale for party that has a whole host of other bits on a list of suspects, without being useful to most other people.
Sure, there are other intelligence agencies, but that's the one I'd be the most worried about. Since either they run it, or they would know of it and want to emulate the idea, or know of it and have access to it from the partner agency running it. Or they are not a threat to me.
There's also the issue of no publicly known cases where someone that used Mullvad being deanonymized through the VPN but instead being discovered through some other opsec failure. If an intelligence agency has this capability they have been sitting on it for almost 2 decades without making use of the data. Hard to believe.
Wow, I didn't realize Mullvad was this old! Then again, maybe they weren't popular enough back then for intelligence agencies to target them? For instance, Mullvad kinda rode WireGuard's popularity wave by being the first(?) VPN provider to implement the protocol. Big ads on billboards came even later. So maybe they only became a target in recent years?
So does your comment...
I don't know the answer, but there are two ways to take it:
1. Submarining to destroy confidence in an actually trustworthy, decent VPN company
2. They're an intelligence front.
For me, Mullvad have the appearance of the greatest likelihood of being legit since they're not aggressively pushing their product with lies and fear mongering. That gels with my vibe. If they're an intelligence front, well, most VPNs probably are as well, so I'm no worse off.
Luckily I'm not doing anything that would get me in the kind of trouble for which multi-jurisdictional cooperation is worthwhile.
I think its safe to assume that intelligence agencies have other options available to them, such as country-wide timing attacks.
Some aspects of the described behavior are as we intended and some are not. The cause is not exactly as described in the blog post. As for mitigation, we are already testing a patch of the unintended behavior on a subset of our infrastructure. If any of you try to reproduce the blog post's findings you may get confusing results throughout the day.
We will also re-evaluate whether the intended behaviors are acceptable or not. Some of this is a trade-off between multiple aspects of privacy, and multiple aspects of user experience.
Please note that this is my current understanding, which may change. I was only made aware of this an hour ago, and most of that time was spent talking with Ops, considering what to do immediately, and writing this post.
Finally, for those of you who do security research: when you find a security or privacy issue, please consider notifying the maintainer/vendor before publishing your findings, even if you intend to publish right away.
It's also worth stating that the client (including the cli client -- which, with a bit of work, you can get running in most situations where you'd use native wireguard) by default has a key rotation interval of I think 72 hours.
`mullvad tunnel get` will show it and `mullvad tunnel set rotation-interval <hours>` will change it. This is the preferred mitigation method of the post.
I personally don't mind having a pseudo-static IP (some other suppliers offer a static IPv4 as a feature!) as I wish to prevent network-level snooping from my ISP and governments. It's also worth stating that I think having a smaller IP space is an advantage for a privacy VPN: there are more potential users acting behind any given externally visible IP. Combined with technologies like DAITA (which effectively adds chaff to the tunnel) and multi-hop entrances and I personally think that this service really does plausibly make harder the life of those who snoop netflows all day.
This was an interesting finding, though as kfreds mentioned it would have been better to notify the vendor before publishing.
The main finding (IP-position-in-pool correlation between servers) seems to include genuinely unintended behaviour. Given our great experience with the Mullvad team, I'm sure this will be addressed soon.
In general, if you want different "identities", you should make sure to rotate or use different WireGuard keys.
One small thing from the article I'll comment on:
> 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).
Context: WireGuard is by design[1] a "Connection-less Protocol", there's no concept of a connection, there's only a "re-keying handshake" (key here refers to the ephemeral Diffie-Hellman key, not the WireGuard key) every 2-3 minutes ONLY IF there's traffic flowing.
The above statement is not too surprising if you consider the counterfactual: What would happen if, even with the same WireGuard key, the exit IP were randomized each time you "connect" to the server (say each time there is a "re-keying handshake" or at more frequent cadence (e.g. every 15 minutes) than the WireGuard key rotation).
In this scenario, ~every 15 minutes:
- At the Transport layer, all your in-tunnel connections that are on non-roaming protocols (basically everything except QUIC) would be disrupted, and the connections would have to be re-established.
- At the Application layer, many application-level sessions that treat "same cookie, new IP" as suspicious would trigger logouts, CAPTCHAs, or risk scoring.
Both are terrible UX, and what's worse would also make users much more uniquely fingerprintable ("this person keeps reconnecting from a different IP, they must be using Mullvad").
Sorta odd you don't support one of Europe's most popular distros.
How to report a bug or vulnerability
... we (currently) have no bug bounty program ... send an email to support@mullvadvpn.net
>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.
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?
Local law enforcement can tap a local ISP for their records, but it would take a scale more effort to then tap a non-local service provider for their records. Each additional level of difficulty adds a cost, and at some point those costs aren't worth the potential results.
(assuming that the VPN provider doesn't just roll over due to an email inquiry, or isn't a front for very cooperative law enforcement).
In theory, but as someone who uses Mullvad in the UK on a day-to-day basis on my personal laptops (not my phone) - I'm using it now, I'm afraid there's quite an additional downside I've found, in that because Mullvad's (at least UK, but also French and Dutch ones I've tried) exit IPs are known, many companies (Cloudflare, Akamai) at the very least know about them, and several sites block access when using Mullvad, returning 403s.
Santander bank for example, I can't always (sometimes I can) connect to when using Mullvad, and sometimes have to turn it off, as I get 403 responses from the bank otherwise (using Firefox).
Sometimes using IPv6 in the Mullvad settings gets around this, but more and more recently I've found it doesn't, so there sites where I'm having to stop using Mullvad to actually access sites.
(I'm still a happy customer, and 1 to 3 are still true and why I use it otherwise).
VPNs are useful for the reasons you mentioned.
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.
They have their own tools + tor, they do not need mullvad.
(yes, I've been raided)
(I started using Mullvad after - because of - that)
(I don't do illegal shit, I just like some obfuscation of my trail because I enjoy fiddling with this stuff - which may have been why I ended up a raid target in the first place)
>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
VPNs are a technical tool for technical people. You need to know exactly why you need it in order for it to be useful.
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.
Yes, obviously.
> VPNs are snake oil
Huh?
If I'm on a public VPN, I don't want anyone to know who is making the request, including the terminating IP.
Think about it. By your logic, VPNs shouldn't be used for torrents because VPNs shouldn't anonymize you to the terminating IP. Whereas they work gangbusters for that.
If you are talking about private VPNs.. Mullvad isn't one.
"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.
If they're checking my locked doors, I don't want them coming in my unlocked doors.
That is a binary thought process with a lot of assumptions. You might introduce even more attack surface in pursuit of this "security" measure by installing additional software like fail2ban, for example. Close your ports, maybe assign a non-standard port to the popular ones (like SSH) to reduce log spam, and patch your server often. Anything more complicated than that is not worth it, IMO.
Like when I was travelling, sites would routinely use the language of my IP address location, not the language preference as I set it in my browser. So I would be served a site that I couldn't read. My only option was to use a VPN to spoof my location so that it would serve me a site in a language I understand.
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.
Things you connect to or log in to are clearly going to be able to ID you at least with in the context of the login that you use regardless of what the VPN does.
I'm logged into HN through Mullvad as it happens. I usually leave it on regardless of what I'm doing because what I'm doing isn't my ISP's business even though I'm pretty happy with them.
Most likely these people just look to hide their torrenting, saying political shit on Twitter from employer and not share their choice of porn with local ISP. Also just adding one more layer between them and occasional scammer who can sometimes infer more broad geodata from their IP leaked from yet another database. Oh and now to avoid "Show your ID" page on the same porn sites.
It works well enough for this goal. Not everyone needs NSA-proof solution.
PS: Obviously more tech savvy people understand importance of hiding traffic on public WiFi, but I doubt average Joe the VPN user will buy VPN for this.
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?
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, and you need to save it forever so that when the NSA asks who used the IP for what duration you can tell them.
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.
It's a practical measure, but definitely has a privacy cost though.
It seems more likely this is just about load-balancing use against their available nodes.
Given how much of the world is stuck behind CGNAT now, I would expect any major sites to handle it.
Edit: In hindsight I regret making this comment. It was unnecessary, but removing it now would look weird.
Putting aside the IP correlation across multiple servers, at first I wondered why even keep the user IP stable on one server. But I think it makes sense because as the author states other VPNs usually have only one IP per server so they are essentially simulating that. The advantages for the user are, if they find a server that works for accessing some service they can connect to that server again and it will work again because they get the same IP.
The IP correlation across multiple servers they should fix though with something like rand.seed(user_pub_key + server_id)
Maybe a clientside hint that gets rotated in some circumstances with options to toggle it off would be appropriate. That should be fine as long as you don't care about someone being able to control their exit IP reliably.
On the flip side, if they’re getting banned by a service because of a noisy neighbor on the same IP, they’d have no way to work around that, no?
1. It's the preferred VPN of TeamPCP.
>The whole operation ran primarily from Mullvad VPN exit nodes and virtual private server infrastructure, with little effort made to blend in. This was a high-tempo, low-stealth campaign designed to extract as much value as possible, as fast as possible.[1]
>Wiz CIRT observed the bulk of TeamPCP’s activity originating from Mullvad Virtual Private Network (VPN) exit nodes and virtual private server hosts such as InterServer.[2]
1: https://www.oligo.security/blog/teampcp-campaign-the-evoluti...
2: https://www.wiz.io/blog/tracking-teampcp-investigating-post-...
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.
What are the chances that someone uses this vpn, joins your forum the day after someone was banned, and has an ip in a similar range?
For most small websites this would be strong evidence.
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?
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.
That's exactly what the article is about, a side channel information leak that de-anonymises users, did you read it?
I'll go ahead and answer that it can't. It knows I'm mullvad user X, thus deanonimization, "it knows I use mullvad", but it doesn't know my original IP, so "it doesn't know I'm me".
VPNs are not 100% anonymous. They are not meant to be. Instead, they are meant to provide some level of privacy to law-abiding adults.
Most people would be embarrassed if their co-workers and neighbors knew the intimate personal details of their lives. Things they like, things they buy, things they do, etc. So, most people should use a VPN to protect their privacy.
By definition, 'most people' don't want or expect 100% anonymity online. They just want a bit of privacy in their personal life and their relationships. That's it.
VPNs don't protect (and are not intended to protect) criminals who want 100% anonymity from governments while committing online crimes. This is an important distinction. 'Most people' are not criminals and do not have this unrealistic expectation from Mullvad and other VPN providers.
I'd not throw the report out just due to what you argue here. These findings are valid nonetheless.
Also if the threat model you're addressing w/ VPN usage is anything other than "I don't want my ISP to know what I'm doing" you need to use/do something else.