Tinycolor supply chain attack post-mortem
28 comments
·September 17, 2025drdrey
> A while ago, I collaborated on angulartics2, a shared repository where multiple people still had admin rights. That repo still contained a GitHub Actions secret — a npm token with broad publish rights. This collaborator had access to projects with other people which I believe explains some of the other 40 initial packages that were affected.
> A new Shai-Hulud branch was force pushed to angulartics2 with a malicious github action workflow by a collaborator. The workflow ran immediately on push (did not need review since the collaborator is an admin) and stole the npm token. With the stolen token, the attacker published malicious versions of 20 packages. Many of which are not widely used, however the @ctrl/tinycolor package is downloaded about 2 million times a week.
I still don't get it. An admin on angulartics2 gets hacked, his Github access is used to push a malicious workflow that extracts an npm token. But why would an npm token in angulartics2 have publication rights to tinycolor?
tetha
> But why would an npm token in angulartics2 have publication rights to tinycolor?
Imo, this is one of the most classical ways organizations get pwned: That one sin from your youth years ago comes to bite you in the butt.
We also had one of these years ago. It wasn't the modern stack everyone was working to scan and optimize and keep us secure that allowed someone to upload stuff to our servers. It was the editor that had been replaced years and years ago, and it's replacement had also been replaced, the way it was packaged wasn't seen by the build-time security scans, but eventually someone found it with a URL scan. Whoopsie.
Terr_
Thinking of biology, the reason often given for the disappearance of "unused" genes is that there's a metabolic cost to keeping them around and copying them on every cell division.
I wonder if someday we'll find there's also an active process that resembles "remove old shit because it may contain security vulnerabilities."
STRiDEX
Sorry if that wasn't clear. This was a token with global publish rights to my npm packages.
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indigodaddy
Anyone know of a published tool/script to check for the existence of any of the vulnerable npm packages? I don't see anything like that in the stepsecurity page.
retlehs
This won’t protect against everything, but it still seems like a good idea to implement:
rectang
Two-factor auth for publishing is helpful, but requiring cryptographically signed approval by multiple authors would be more helpful. Then compromising a single author wouldn't be enough.
tcoff91
Many packages have only 1 author.
rectang
The conclusion I'm coming to is that depending on packages which only have a single author is problematic. There are too many ways that packages published by one person can be compromised.
Packages which don't have approval and review by a reliable third party shouldn't be visible by default in a package manager.
Hackbraten
How are you supposed to gain collaborators for a project that no one can possibly find?
chrisweekly
and (as in this case), that 1 author may use a single token to authz publishing many packages
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bikeshaving
> Local 2FA based publishing isn’t sustainable...
Why is local 2FA unsustainable?! The real problem here is automated publishing workflows. The overwhelming majority of NPM packages do not publish often enough or have complicated enough release steps to justify tokens with the power to publish without human intervention.
What is so fucking difficult about running `npm publish` manually with 2FA? If maintainers are unwilling to do this for their packages, they should reconsider the number of packages they maintain.
STRiDEX
That's fair, I'm referring to the number of mistakes that happen with local publishing. Publishing the wrong branch, not building from latest etc
skydhash
So add a wrapper for that, a quick script that checks which branch and revision you are publishing from. The issue here is publishing from a CI you do not control that well and with automated events.
paxys
You can run the exact same script locally as you do in CI, with the only difference being the addition of a 2FA prompt.
cyberax
> exfiltrated a npm token with broad publish rights
I freaking HATE tokens. I hate them.
There should be a better way to do authentication than a glorified static password.
An example of how to do it correctly: Github as a token provider for AWS: https://aws.amazon.com/blogs/security/use-iam-roles-to-conne... But this is an exception, rather than a rule.
chatmasta
These machine-to-machine OIDC flows seem secure, and maybe they are when they’re implemented properly, but they’re really difficult to configure. And I can’t shake the feeling that they’re basically just “tokens with more moving parts,” at least for a big chunk of exploitation paths. Without a human in the loop, there’s still some “thing” that gets compromised, whether it’s a token or something that generates time-limited tokens.
In the case of this worm, the OIDC flow wouldn’t even help. The GitHub workflow was compromised. If the workflow was using an OIDC credential like this to publish to npm, the only difference would be the npm publish command wouldn’t use any credential because the GitHub workflow would inject some temporary identity into the environment. But the root problem would remain: an untrusted user shouldn’t be able to execute a workflow with secret parameters. Maybe OIDC would limit the impact to be more fine-grained, but so would changing the token permissions.
tetha
Hence you need to start thinking about threat models and levels of compromise, even in your build system.
If I control the issuing and governance of these short-lived secrets, they very much help against many attacks. Go ahead and extract an upload token for one project which lives for 60 seconds, be my guest. Once I lose control how these tokens are created, most of these advantages go away - you can just create a token every minute, for any project this infrastructure might be responsible for.
If I maintain control about my pipeline definition, I can again do a lot of work to limit damage. For example, if I am in control, I can make sure the stages running untrusted codes have as little access to secrets as possible, and possibly isolate them in bubblewrap, VMs, ..., minimize the code with access to publishing rights. Once I lose control about the pipeline structure, all that goes away. Just add a build step to push all information and secrets to mastodon in individual toots, yey.
To me, this has very much raised questions about keeping pipeline definitions and code in one repository. Or at least, to keep a publishing/release process in there. I don't have a simple solution there, especially for OSS software with little infrastructure - it's not an easy topic. But with these supply chain attacks coming hot and fast every 2 weeks, it's something to think about.
chatmasta
But the token wasn’t the primary source of compromise here. It was the GitHub workflow which had the token embedded into it. There was no need for the actor to exfiltrate the token from the workflow to somewhere else, because they could simply run arbitrary code within the workflow.
It would have made little difference if the environment variable was NPM_WEBIDENTITY instead of NPM_TOKEN. The workflow was still compromised.
er4hn
Well the idea behind tokens is that they should be time and authZ limited. In most cases they are not so they degrade to a glorified static password.
Solutions like generating them live with a short lifetime, using solutions like oauth w/ proper scopes, biscuits that limit what they can do in detail, etc, all exist and are rarely used.
undecidabot
Trusted publishing is a thing now for many package registries, including npm: https://github.blog/changelog/2025-07-31-npm-trusted-publish...
skydhash
As another sibling have put it, it probably should be short lived or behind a manual verification (passphrase, 2fa,…)
> That repo still contained a GitHub Actions secret — a npm token with broad publish rights.
One of the advantages of Trusted Publishing [0] is that we no longer need long-lived tokens with publish rights. Instead, tokens are generated on the CI VM and are valid for only 15 minutes.
This has already been implemented in several ecosystems (PyPI, npm, Cargo, Homebrew), and I encourage everyone to use it, it actually makes publishing a bit _easier_.
More importantly, if the documentation around this still feels unclear, don’t hesitate to ask for help. Ecosystem maintainers are usually eager to see wider adoption of this feature.
[0] https://docs.pypi.org/trusted-publishers/