Tailworm – Tailscale Vulnerabilities

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

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

That said, these vulnerabilities aren't that significant.

Meh.

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).

The primary finding relevant to most users is the privilege escalation vulnerability in the opensource tailscale ssh server, when port forwarding is enabled (default), users may escalate privileges to root on the destination server.

The secondary finding is the ability to route to arbitrary subnets accessible via a host offering an App Connector. This is the one that really worries me, in regard to impact.

The third most important finding may be the `tailscale serve` authz bypass opportunity, but I suspect this may not impact many users. It may be significant in unlucky configurations.

Much of the report focuses on the security model and architecture of the software, with explanations of live scenarios conducted in our lab. Our concern is that an attacker could establish a foothold via something like a PHP exploit or supply chain exploit on a host, then `tailscale ssh` to another host and escalate, or route through an App Connector. They may even leverage the tailscale serve authz mechanism for an app-level privilege escalation for lateral movement. It is true that well managed policies mitigate some of these risks.

This report was called Tailworm because the research focused on the threat of a worm against an opensource headscale+tailscale network, and the capabilities of our agentic systems to defend autonomously against lateral movement across our systems. Our lab focuses on building secure infrastructure for recursive self improving intelligence, and this was the report from the red side of the experiment.

Finally, I believe we live in an age of continuous disclosure, continuous development, continuous integration, and continuous deployment. That's how we get through this.