blog.pypi.org
Mike Fiedler
PyPI Admin, Safety & Security Engineer (PSF)

Shai-Hulud is a great worm, not yet a snake. Attack on npm ecosystem may have implications for PyPI.

PyPI and Shai-Hulud: Staying Secure Amid Emerging Threats
An attack on the npm ecosystem continues to evolve, exploiting compromised accounts to publish malicious packages. This campaign, dubbed Shai-Hulud, has targeted large volumes of packages in the JavaScript ecosystem, exfiltrating credentials to further propagate itself.

PyPI has not been exploited, however some PyPI credentials were found exposed in compromised repositories. We've revoked these tokens as a precaution, there's no evidence they have been used maliciously. This post raises awareness about the attack and encourages proactive steps to secure your accounts, especially if you're using build platforms to publish packages to PyPI.

How does this relate to PyPI?
This week, a security researcher disclosed long-lived PyPI credentials exposed as part of the Shai-Hulud campaign. The credentials were found in GitHub repositories (stored as repository secrets), and were still valid. We saw an attack with insecure workflow settings for Ultralytics in 2024.

While the campaign primarily targets npm, some projects use monorepo setups, publishing both JavaScript packages to npmjs.com and Python packages to PyPI from the same repository. When attackers compromise these repositories, they can extract credentials for multiple platforms.

We investigated the reported credentials and found they were associated with accounts that hadn't published recently. We've revoked these credentials and reached out to affected users to advise them to rotate any remaining tokens.

What can I do to protect my PyPI account?
Here are security practices to protect your PyPI account:

Use Trusted Publishing: If you are using a build platform to publish packages to PyPI, consider using a Trusted Publisher. This eliminates the need to manage long-lived authentication tokens, reducing the risk of credential exposure. Trusted Publishing uses short-lived, scoped tokens for each build, minimizing the impact of any potential compromise. This approach has risen in popularity, with other registries like Crates.io, RubyGems, and npmjs.com adopting similar models.

When using GitHub Actions, consider layering in additional security measures, like requiring human approval via GitHub Environments before publishing. This blog post from pyOpenSci has detailed guidance on adding manual review steps to GitHub Actions workflows.

Audit your workflows for misconfiguration: Review your GitHub Actions workflows for any potential security issues. Tools like zizmor and CodeQL can help identify vulnerabilities in your CI/CD pipelines. Adopt scanning as automated actions for the repository to catch future issues.

Review your account activity: Regularly check your PyPI account activity for any unauthorized actions. If you notice any suspicious activity, report it to the PyPI security team immediately.

Taking any of these steps helps mitigate the risk of compromise and keeps packages secure.

blog.pypi.org - The Python Package Index Blog - PyPI now checks for expired domains to prevent domain resurrection attacks, a type of supply-chain attack where someone buys an expired domain and uses it to take over PyPI accounts through password resets.

These changes improve PyPI's overall account security posture, making it harder for attackers to exploit expired domain names to gain unauthorized access to accounts.

Since early June 2025, PyPI has unverified over 1,800 email addresses when their associated domains entered expiration phases. This isn't a perfect solution, but it closes off a significant attack vector where the majority of interactions would appear completely legitimate.

Background
PyPI user accounts are linked to email addresses. Email addresses are tied to domain names; domain names can expire if unpaid, and someone else can purchase them.

During PyPI account registration, users are required to verify their email addresses by clicking a link sent to the email address provided during registration. This verification ensures the address is valid and accessible to the user, and may be used to send important account-related information, such as password reset requests, or for PyPI Admins to use to contact the user.

PyPI considers the account holder's initially verified email address a strong indicator of account ownership. Coupled with a form of Two-Factor Authentication (2FA), this helps to further secure the account.

Once expired, an attacker could register the expired domain, set up an email server, issue a password reset request, and gain access to accounts associated with that domain name.

Accounts with any activity after January 1 2024 will have 2FA enabled, and an attacker would need to have either the second factor, or perform a full account recovery.

For older accounts prior to the 2FA requirement date, having an email address domain expire could lead to account takeover, which is what we're attempting to prevent, as well as minimize potential exposure if an email domain does expire and change hands, regardless of whether the account has 2FA enabled.

This is not an imaginary attack - this has happened at least once for a PyPI project back in 2022, and other package ecosystems.

TL;DR: If a domain expires, don't consider email addresses associated with it verified any more.

blog.pypi.org - - The Python Package Index Blog - PyPI Users are receiving emails detailing them to log in to a fake PyPI site.

PyPI has not been hacked, but users are being targeted by a phishing attack that attempts to trick them into logging in to a fake PyPI site.

Over the past few days, users who have published projects on PyPI with their email in package metadata may have received an email titled:

[PyPI] Email verification

from the email address noreply@pypj.org.

Note the lowercase j in the domain name, which is not the official PyPI domain, pypi.org.

This is not a security breach of PyPI itself, but rather a phishing attempt that exploits the trust users have in PyPI.

The email instructs users to follow a link to verify their email address, which leads to a phishing site that looks like PyPI but is not the official site.

The user is prompted to log in, and the requests are passed back to PyPI, which may lead to the user believing they have logged in to PyPI, but in reality, they have provided their credentials to the phishing site.

PyPI Admins are looking into a few methods of handling this attack, and want to make sure users are aware of the phishing attempt while we investigate different options.

There is currently a banner on the PyPI homepage to warn users about this phishing attempt.

Always inspect the URL in the browser before logging in.

We are also waiting for CDN providers and name registrars to respond to the trademark and abuse notifications we have sent them regarding the phishing site.

If you have received this email, do not click on any links or provide any information. Instead, delete the email immediately.

If you have already clicked on the link and provided your credentials, we recommend changing your password on PyPI immediately. Inspect your account's Security History for anything unexpected.