NIST deprecates RSA-2048 from 2030. Find every one of them before attackers do.
Part of a larger attack: @posthog published 56 malicious packages. See the full campaign →
Malicious package

@posthog/piscinanpm

Advisory published Updated

@posthog/piscina is a confirmed malicious npm package (MAL-2025-190750) that steals credentials and exfiltrates sensitive data (malicious version 3.2.1). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in @posthog/piscina (npm)

MAL-2025-190750
Immediate action
Remove the package, then rotate any secrets the build/runtime could reach.
npm uninstall @posthog/piscina

What this malware does

The package @posthog/piscina was found to contain malicious code.

Any computer that has this package installed or running should be considered fully compromised. All secrets and keys stored on that computer should be rotated immediately from a different computer. The package should be removed, but as full control of the computer may have been given to an outside entity, there is no guarantee that removing the package will remove all malicious software resulting from installing it.

This package was compromised by the Sha1-Hulud: The Second Coming NPM worm. The malicious payload steals tokens and credentials and publishes them to GitHub. The worm will propogate itself to NPM packages the user owns and establish persistence is a GitHub action. The package may also destroy the user's home directory.

Malicious versions

1 flagged
3.2.1

Indicators of compromise (SHA-256)

731794a5898b7ca6049626b91dad59ed65293d59335397c1989a1b45a498cb9f
ebd3d94d864b267499cd7c7897fa7fc4af2c420f3aa6bd152a0b22feae86418b
e022ef565665ae5f925ddcfdd466eb608b6275ff233226d66d93bb844d81b4ba
f9c3b0b0932078a8c893566cc3e18f78201efe7a5efbe9adde6efb022a2f4ba0

Detection & response playbook

Credential / info stealer

  1. Find it

    Search your lockfiles and build artifacts for @posthog/piscina (version 3.2.1).

  2. If you installed it — respond

    @posthog/piscina is built to steal secrets, so assume every credential the build or runtime could read is compromised. Remove it from your project and lockfile, then rotate ALL exposed secrets — npm/registry tokens, cloud keys, CI/CD secrets, SSH keys, and any .env values — from a known-clean machine. Audit logs for unauthorized use of those credentials.

  3. Did it already run?

    If @posthog/piscina was installed, its post-install payload may already have run. Removing the package does not undo that — check outbound connections and credential use from the install window onward.

Frequently asked questions

No. @posthog/piscina on npm has been identified as a malicious package (version 3.2.1 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

GHSA-v2pm-8g3h-7h3r

References

Credits

  • Amazon Inspector · finder

Detect & block this

O3 blocks @posthog/piscina-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the credential exfiltration and severs the channel.

Malware detection Runtime egress monitoring

Explore

All malware advisories How O3 detects malware Vulnerability database
@posthog/piscina (npm) malicious package — MAL-2025-190750 | O3 Security