I wanna know if MATRIX recipients know my IP, and more globally what the recipients know about me (how the matrix protocol works). THX
No, the only one that knows your IP is your server. So your server knows your IP because you talked to it and the server knows the recipient servers IP because that’s who you’re sending to. And the recipient knows their servers IP but doesn’t know your servers IP and doesn’t know your IP. Now you can find the recipient servers IP by doing a ping obviously and they can find your servers IP that same way but they can’t find your IP directly and you can’t find their IP directly. Now, this may change for audio calls because that uses WebRTC, but I can’t speak to that.
So why some nerds saying matrix as a metadata disaster?
Because encryption doesn’t work for rooms over 50 people, so any room over that size is public by default. And most of the usage is the Matrix.org home server.
Even if I selfhost?
If you self-host, it’s better, but it’s still not great. The people would then know the IP address of your server that you were hosting it on, so you’d have to make sure it was a VPS and not done from home.
You could also put it behind a cloudflare proxy subdomain, right? That way it looks like the origin ip comes from cloudflare
Ugh, Yes, you could. But, Cloudflare.
What about using a normal, non-Cloudflare VPS for this?
Because encryption doesn’t work for rooms over 50 people, so any room over that size is public by default.
By public you mean non-encrypted? How does that work? When you create a room, you default to encryption, and there is only one participant (the room creator). And you cannot turn off encryption, so what then happens when you get 51 participants?
Also existing non-encrypted rooms are never automatically switched to encryption, so the switch must be explicit. Does it refuse to do it if there are more than 50 participants?
I’ve never heard of this limit nor was I able to find info about it (so a link would be great), but there could some factor that increases problems as the number of people increases… Perhaps 50 is some practical suggestion for the maximum number of people to have in encrypted sessions?
I got the 50 from this video.
Thanks!
The mention was at about 12:06, in the form that OLM breaks down at about 50 users “give or take”, so it’s not really a limitation imposed by the system itself and it would be difficult to impose it. I doubt this is the experience of all Matrix e2ee users at least at that exact point, but e2ee has always had some growth pains, so there could people with those issues; on the other hand few large rooms are e2ee to begin with, so experience on those is limited. E2ee also requires the users to be more mindful about their data as in not to lose their private keys, and these problems probably increase linearly as the room size increases.
I didn’t notice any claim of rooms larger than 50 becoming public.
I’ve only heard a second-hand info about it, but apparently one local policital party uses e2ee in Matrix with hundreds of people in the room, so that should be a proof that the encryption is not limited to 50 users—and this info sounds just as well founded as the information provided by the video ;).
The guy carries on stating that pretty much all of the huge matrix rooms are not end-to-end-encrypted, and I have no reason to doubt that. Personally I see little point in having such large rooms encrypted anyway, because if you have a large room you will also likely have very relaxed checks on who gets to enter it (e.g. it could be completely public), and if that’s the case, then so can any party who wishes to monitor the room join the room as well. E2ee won’t be protecting those cases. (While at the same time you lose server-side search feature and efficient notifications, though at least the latter one is being fixed with out-of-envelope notification data—which again leaks a bit more metadata…)
The video also makes it sound like that if you have a Matrix Home Server in the network, it’s going to end up hosting CSAM. This is only the case if one of the users of that HS are in a room that has the content, so it’s not like it will just automatically get migrated there. I imagine vast majority of Matrix Home Servers have limited account creation abilities (e.g. companies, personal home servers, organizations, etc), eliminating or at least highly discouraging this kind of issue.
Btw, the video makes an excellent point about the Matrix CDN issue, which is being fixed currently as well (that change is already merged to the matrix spec), by requiring authentication. Next steps is going to associate media to messages, making this kind of thing even more strict. All this means IRC bridges will need to start hosting Matrix-side contents by themselves, though…
Because there is a lot more metadata than just IP addresses.
Human behavior is funny, isn’t it? No matter what the topic, there are always people around who like to repeat criticism they heard from someone else, even if it’s so vague as to be useless (“metadata disaster”) or they don’t understand the details at all.
It’s not a disaster. A few minor bits of metadata (avatars and reactions, IIRC) haven’t been moved into the encrypted part of the protocol yet. If that’s a problem for your use case, then you might want to choose a platform with different flaws, or simply avoid those features. It’s already good enough for the needs of many privacy-minded folks, though, and it continues to get better.
There is a lot more metadata than just avatars and reactions. Accounts and their room membership over time, timing of messages (and thus online times), individual interactions between specific users (based on the timing of their messages) and so on. That is all in the unencrypted metadata of a Matrix room and can’t be moved to the encrypted message part like avatars and reactions.
The network layer of all internet servers reveals almost everything you listed. Signal has the same problem, and there’s nothing they can do about that. The only way to avoid it is to use a completely peer-to-peer model (Matrix has started work on this, btw) and avoid communicating across network routes that can be monitored.
There might be one exception, depending on what you mean by “Accounts”: The user IDs participating in a room can be seen by server operators and room members. But then again, server operators can already see their users’ IP addresses (which is arguably more sensitive than a user ID), and I believe room members have to be allowed into the room in order to see them. For most of us, that’s fine. Far from a disaster.
No, because Matrix stores all this info and gives it freely to other servers retroactively(!). Also with network layer sniffing (which is anyway much harder to do) you can only see which home-server talked to with other homeserver and what clients talked to their homeserver. If you have the full room meta-data you can easily make a social graph of which account talked to whom when and where.
Matrix stores all this info and gives it freely to other servers retroactively(!)
Can you show me the part of the spec that allows a server with no room members to get private room info from another server? I’m skeptical, but if true, I believe that would be worth reporting as a bug.
network layer sniffing (which is anyway much harder to do)
You’re funny.
Obviously you need someone joining the room for the room metadata to be shared between homeservers. But that is really only a minor barrier and once that has happened the worst case scenario takes place immediately. On other messengers (federated or not) a newly joining member has very limited access to past room metadata. Not so with Matrix, where a joining homeserver get full retroactive access to all the room metadata since the room’s creation. If you can’t see the problem with that, you really need to stop privacy LARPing 🙄
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It’s not a disaster. That’s overstating it. It just leaks some metadata to the server. Nothing that’s inherently wrong with it and which won’t be solved over time.
Some may don’t like that everything is stored on the server compared to signal where it only transits the server. But for companies or gov that should be/is mandatory. And it makes handling cross client and updating devices a lot easier for normal consumers.
You seem to be unaware of how Matrix works. It is inherent to the protocol that room metadata is shared with other servers. It is not fixable as it is working as intended. This feature is nice for censorship resistance, but it is pretty much a nightmare for metadata privacy.
I’m mot aware of a critical metadata leak, a link or example would be really helpful. Thanks!
Like all of it. It is not a “leak” if it is working as intended.
Anyone can spin up a Matrix server, join a room with it and the Matrix network will happily push a complete copy of the room metadata (all the way back to the point the room was first created) to that new homeserver.
There’s no problem for a public room. You can’t just join a private room.
Yes it is a problem for both public and private rooms as this info is stored and shared retroactively. Lets say one of the participants of a private room gets compromised or you invite someone that has their account on a compromised homeserver. This then results in the entire room meta-data history (since the room was created) being shared with that compromised homeserver which can then easily analyse it in detail.
I figure that the administrators of your homeserver could see your IP address, I doubt that it would be sent to anyone you are just chatting with.
Did you make a call?
No
Then maybe you’re okay.
A number of people can see your IP, people will chime in and add to ane remove from this list:
Can’t see it:
- Random people you personal message with
- Random people you chat with in rooms
CAN see it:
- Server admins
- People you share (send/rcv files with) // this may have been fixed
- People who send you links and you click them, but this isn’t specific to Matrix, it’s a tale as old as time.
- You voice call with someone (may have been fixed)
Some info may be wrong. But having someone’s IP in the days of routers and all filtered ports means little, unless you piss off someone who knows some low level customer support person @ your ISP to pay to get your account info. Or you’re dealing drugs in which case use TAILS and stop fucking with technologies you don’t know the specifics of.
If they knock you offline and you can’t access anything at all, unplug your router AND MODEM (most importantly your modem) for an hour. Go touch grass for an hour. Widdle a wee branch. Plus your boxes back in and you’ll be bright as new.
@[email protected] this isn’t meant to be a dig at you, although last time you didn’t care to correct or learn if I recall,but often times you leave out the “if so,” “possibly, what and XYZ?'” and it ends up spreading misinformation because you didn’t know enough or care enough to type enough.
I love Matrix but we need to be open about what the fish is before skinning it…
https://gist.github.com/maxidorius/5736fd09c9194b7a6dc03b6b8d7220d0
https://blog.erethon.com/blog/2022/07/13/what-a-malicious-matrix-homeserver-admin-can-do/
https://www.reddit.com/r/PrivacyGuides/comments/q7qsty/is_matrix_still_a_metadata_disaster/
This thing is really scary, any other articles?
Do a lot of reading. Get a cyber informations systems basics overview on your own self-teaching before you try to understand it all.
Stay away from session and matrix. Signal, Nostr, SimpleX (nvm if you use Apple products) and the like are okay, but they are all hobbyist influencable products besides Signal which gets fat government grants and just happens to use the same encryption standards as all other huge name E2EE tools.
Stuff is fun to learn on, but get a good VPN (debates about… mullvad, ivpn, cryptostorm seem okay). here’s something fun for you and free: https://www.thc.org/segfault/
So Matrix protocol is bad because criminals use it to distribute illegal content. That’s the same as saying Tor is bad because people use it to do illegal things on the dark web. Matrix is just a protocol which powers a decentralized network. Is it better to have proprietary centralised platforms where a small number of people control everything?
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