| layout | post |
|---|---|
| title | Privacy: Mitigating User Tracking By Third Parties |
| lang | en |
| author | rdica |
| heading | Privacy: Mitigating User Tracking By Third Parties |
By default the Jamulus protocol does not map usernames to IP addresses in any publicly available data.
However it is possible to correlate connections to Servers to achieve user<‐>IP mapping.
This was first reported to Jamulus developers here: https://github.com/orgs/jamulussoftware/discussions/3545
This document will attempt to summarize the problem, and provide mitigations for both users, and Server admins.
When a user attempts to connect to a Server, they open the Connect dialog window. The client will start sending “pings” to every Server listed in that genre to report delay latency (basically network distance) to those Servers.
Anyone running a Server can capture those “pings” using tools like tcpdump or tshark/wireshark and view the IP addresses of the clients that are sending them.
No username data is sent. This is part of the Jamulus protocol, by design, to maintain a level of privacy and prevent others from finding the IP addresses of specific users.
A user will either select a Server from the list, or type in a Server address:port, click Connect or hit Enter, and the client will then attempt to connect to the Server. At this point the client stops sending the “pings” and the client typically completes the connection to the Server.
Each genre has a Directory Server. The purpose of the Directory Server is to provide clients with a listing of Servers registered to it, and the users connected to each Server. This is public data, and viewed in the Connect dialog window, and available through a number of websites, like explorer.jamulus.io, jamulusjams.com, or jamscout.de.
Anyone can run an explorer instance. An explorer queries each genres Directory Server to get a list of Servers, then queries each Server directly to get a list of connected users. This is public data. There is no IP address information on users, just the user profile data. Again this is by design to prevent IP<‐>username mapping. This data can also be saved for later processing.
Anyone can run Servers and explorer instances.
Using IPs captured by a Server, one can correlate when an IP address stops pinging (ie; just connected to a Server) and when a new client joined a Server (username data from explorer query directly to a Jamulus Server) to produce an IP<‐>username mapping. The IP address can then be processed to provide geolocation data. From this one can determine the approximate location of a specific user.
There are currently seven known Servers on public Jamulus space, one in each genre. They are hosted on DigitalOcean instances. They are named Duet, and have a userlimit set at two. They all share the same IP and each sit on different ports.
These Servers are “listening” for pings from clients, and packet capturing them to get the IP addresses of user clients.
Genre Name IP:port
Any Genre1 Duet 24.199.107.192:22121
Any Genre2 Duet 24.199.107.192:22122
Any Genre3 Duet 24.199.107.192:22123
Rock Duet 24.199.107.192:22124
Jazz Duet 24.199.107.192:22125
Classical/Folk Duet 24.199.107.192:22126
Choral/Barbershop Duet 24.199.107.192:22127
There is an explorer instance collecting lists of Servers and users running from 137.184.43.255. It is hosted on a DigitalOcean instance.
IP addresses of users collected from the listeners are being correlated with join events derived from the explorer instance to produce IP<‐>username mappings. IP addresses are processed to provide geolocation data of users. This geolocation data is being collected and displayed without express permission of users, and with no means to opt in or out.
When you open the Connect dialog window your client starts sending pings to every Server in the list. 24.199.107.192 is the IP address of one of those Servers. A Server using 24.199.107.192 exists on each genre, their names are Duet.
Blocking outgoing UDP traffic on your DAW or router to 24.199.107.192 will prevent the listeners from collecting your IP address and breaks correlation. This will help prevent you from being tracked.
Server admins can decide to prevent user tracking by blocking the explorer probe.
If you run a Server on the Jamulus public network, it is currently being indexed by the explorer instance on 137.184.43.255
Blocking incoming UDP traffic from 137.184.43.255 will prevent the explorer from indexing your Server and breaks correlation. This will disable user tracking on your Server from the blocked Server.
Updated information can be found here: https://jamulusjams.com/block-user-tracking.html