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Thanks for the blog post. I am following the project closely since Brad announced working for you. My main concern currently is the coordination server which d
by tux21b 7y ago
Thanks for the blog post. I am following the project closely since Brad announced working for you.
My main concern currently is the coordination server which does not fit the zero trust claim.
I know that the traffic between peers is end-to-end encrypted and you did a good job designing your DERP protocol. However, the ability of the coordination server (login.tailscale.com) to add arbitrary nodes to my private network without my consent scares me.
Maybe you can use Wireguard's PSK to add an additional pre-shared-key to all nodes that is not managed by the coordinator (and never transferred to it)? This would make the setup slightly more difficult (you need to login to tailscale.com AND you need to provide your PSK), but it would at least ensure that the system can never talk to foreign nodes added by the coordinator itself (because the foreign nodes do not know the PSK).
If you already use the PSK for something else, another passphrase/key-file that is never transmitted and is XOR'ed over the PSK will do the trick. The firewall configuration that is pushed to all clients should be probably signed by a local key too, since it is rather critical.
Another possible attack of the coordinator would be if he pushes a configuration with correct VPN IPs and correct public keys, but changes the mapping between them. Since the IP within a wireguard network is usually used as an identity, this might be a huge problem.
- mrlambchop 7y agoWell, this just listed out my concerns pretty well and I spent the last hour installing this on my devices. Specifically, how do I explain to a fortune 500 IT department how this is secure in a few simple sentences?
- crawshaw 7y agoLarge companies that want to remove us from the trusted group should run the coordination server on-prem. We have considered other certification options, but so far they boil down to running a part of the coordination server on-prem. Still exploring the space though. (I work at Tailscale)
- tux21b 7y agoSure, large companies can easily run a on-premise coordination server. But large companies usually also have a network department and several other SDN and VPN solutions already. They are probably using highly tuned and standardized ipsec tunnels with hw accelerated AES encryption and special devices from different vendors. I think tailscale could become the #1 solution for personal users and small / mid-sized companies (some of them might not even have an IT dept). At least the easy installation, the single process design (no separate IKE service etc.) and the opinionated modern cryptography - that deliberately does not allow any configuration at all - would make it a really good candidate for those use cases. This users can probably rent a cheap $3 VPS easily and use it as an on-prem coordination server. However, this increases the installation effort considerable and trusting the cheap $3 VPS to be an essential part of your cooperate network might be a deal breaker. Many of those users might not even have a dedicated team for server maintenance and might not apply security updates regularly. So, please add an (optional) additional PSK (or key pair / certificate) to each node that is not shared with the coordination server and can be used to sign / verify the configuration on each client. Users that do not care don't have to specify anything (they just have to log-in and everything works). Users that do care would have to login and provide the PSK on each device. (And to be clear, the problem is not that I do not trust you. I am sure you are doing a great job and I would really like to use your service. But you are an US based company and with the new data protection laws within the EU it might not be easy to convince all customers that potentially sending all their data to a third-party company within the US is necessary.)
- lonelappde 7y agoAre large companies your target market?