Tailworm – Tailscale Vulnerabilities | Hacker News Reader

Tailworm – Tailscale Vulnerabilities

tailworm.com

The VP of engineering at tailscale did post a response here:

https://www.reddit.com/r/Tailscale/comments/1xeoj1l/recent_t...

This was very hard to read and this author didn't report their findings to security@tailscale.com either, which is irresponsible.

It was reported but not coordinated.

Which is... irresponsible!

Reserving any judgement on the actual vulnerability or disclosure process - It was still very hard to read, and not because the topic was hard - the writing just sucked.

TIL I'm a Tailscale developer

> This report strictly audits the open source software provided to users under no condition of warranty per the BSD-3 license. As such, the researchers, and the users, are effectively developers of said software per its open source nature.

Can people please stop flagging comments by the primary participants? Flagging is just hiding things, if you want to attack what they write, respond with words!

Looks like AI slop and certainly not wormable in the traditional sense. Hard to imagine that your access to a Tailscale SSH server would then allow further replication, and certainly it would not allow for meaningful cross-tenant replication.

Seems like they responded on Reddit: https://www.reddit.com/r/Tailscale/comments/1xekjpd/tailworm...

This is just slop, even if any of the issues raised here are real or not, no human bothered to want to contribute to its authorship. The linked website is something like 10,000 words that by and large convey nothing useful to the reader. HN is going to need a flag for these articles so nobody wastes and time under the illusion that there’s anything worth reading.

Why?

Some of these vulnerabilities are critical. One compromised node with ssh can get root every other node.

Calling it slop, AI, conveys nothing, 10000 words does not help. They provide practical demonstration, and explain the cause.

In my opinion tailscale needs to focus on secure networking. File sharing, DNS, SSH, Funnel, ... can be handled by dedicated tools.

How many lines of code is tailscale client nowadays?

If you were in college this would be a 40 page essay, or about the same length as thesis in some cases, to communicate a list of potential software vulnerabilities in an overly verbose, pompous voice. It's just slop, it could have been a couple of paragraphs of text at most.

ssh/tailssh/tailssh.go:576

Tailscales architecture of increasing its scope while having insufficient isolation is why I don't use it. (I just want the mesh, but their non-root setup instructions are now gone!)

That said, these vulnerabilities aren't that significant.

Meh.

there are fair and not fair points in all this (too much AI?).

to be fair, config choices like tailnet lock and ephemeral keys can be used to mitigate.

however, the enumeration of the entire tailnet leading to one compromised node providing the whole map (e.g. hugging face) is inherent in their architecture. that one can be mitigated by ACLs for small networks, but that is unwieldy at scale.

i do have to agree that tailscale is a vpn - which is not easily reconfigured to follow more zero trust principles. so their zero trust washing marketing is disingenuous. they could stick with their strength: an easy to use version of a great vpn (wireguard).

(tailscalar here): it's been a long day working on this, and we will have more details to follow. quickly though, on this point about enumeration, some of this may be a difference in headscale. the tailscale control plane performs what we colloquially refer to as "netmap trimming" - if node a has no acls that allow it to do anything with node b, then neither a or b would see each other in their netmap.

appreciate your hard work and ts in general.

trimming is a neat feature - thanks for that - thought the ACLs are often not there to begin with because configuring off the full node level access defaults of the vpn is difficult, at least at scale.

not specific to ts - all vpns and firewalls have the same intrinsic issue.

I am not sure if it is actually true for TS. From what I understand the nodes advertise themselves in a different mechanism than what provides access. ACLs are set globally and the nodes fetch them.

So even with 0 access ACLs for node-to-node communication, nodes can advertise themselves to the control plane and change their config as the ACLs are updated.

The following are from my own adventures in heavily customizing headscale and interacting with tailscale client:

Nodes get "NetMap" streamed to them from control plane, which contains information about nodes accessible to them. Without a node showing up in netmap, you can't start discovery to connect to that node - discovery protocol follows once you get information for given node, and allows continued connection in case NetMap gets stale (but if ACLs are changed and reach the other node, it's going to filter you out, and you're not going to know about it without initial info from NetMap)

Pretty sure only accessible nodes are present in netmap given to a node from headscale.

... Because I had triggered more than one alarm recently messing with a headscale upgrade and permissions involved :D

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