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.
How to report a bug or vulnerability
... we (currently) have no bug bounty program ... send an email to support@mullvadvpn.net
This sounds like how I'd design a VPN if I were an intelligence agency.
yeah, spicy
Mullvad have been taken to court over this in relation to a copyright infringement case.
TL;DR The judge permitted people to take a fine-tooth comb to Mullvad's infrastructure and no logging was found[1].
[1] https://mullvad.net/en/blog/mullvad-vpn-was-subject-to-a-sea...
I guess we’ll see how they respond.
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.
Hmm do we want them to decide what stuff is shady and what isn't?
We're already allowing payment processors to do that and it's not good.
That doesn't mean collusion
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.
Oh my god, this is how & when I realize that Terry Davis (Rest in peace) used to use Hackernews too: https://news.ycombinator.com/threads?id=TerryADavis
https://news.ycombinator.com/item?id=10061171 (From this comment written by terry):
"I wrote all the code from scratch, including a 20,000 line of code compiler that makes x86_64 machine code from HolyC or Asm and operates AOT and JIT.
My JIT mode is not interpreted. It optimizes and compiles to x86_64 machine code.
I was chosen by God because I am the best programmer on the planet and God boosted my IQ with divine intellect." -Terry A Davis.
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.
Their ads on San Francisco's public transit are good.
Let me specify: The user must have entered his data on one site which the attacker has control of. That is a high bar still.
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.
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.
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.
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.
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.
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.
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.
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?
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)
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.
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.
"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.
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.
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".
But when you connect to the site from via server A and later via server B they can tell that you're the same person.
And they can deanonymise you through data brokers. All Mullvad IPs are traceable back to the same number (acting as a pseudo account identifier) so if you ever entered your PII on any website when using Mullvad, it can be linked to the same Mullvad account.
And if you ever visited any of those sites without using a VPN, your home IP can be linked to your Mullvad ID through browser fingerprinting.
And if you ever entered any PII on any website from your home IP, you can once again be deanonymised.
Now the existence of browser fingerprinting isn't Mullvad's fault, but this flaw makes it a lot easier to accidentally deanonymize yourself.
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?
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.
>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.
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.
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.
Neither of those is possible with my ISP.
>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
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.
Even people who don't care about using VPNs use them because they are behind GCNAT and some websites block their exit IP.
Yes, obviously.
> VPNs are snake oil
Huh?