Which versions of @posthog/siphash are malicious?

The following npm versions of @posthog/siphash are flagged malicious: 1.1.2. Treat any of these as compromised.

How do I remediate @posthog/siphash if I installed it?

@posthog/siphash 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.

I already installed @posthog/siphash — how do I know if it already compromised me?

If @posthog/siphash was ever installed, its post-install/runtime payload may have already executed. O3's L7 egress monitoring and runtime eBPF sensors detect the credential exfiltration or command-and-control callback after install and block the malicious outbound channel, so you catch and contain the actual compromise — not just the presence of the package.

Is @posthog/siphash part of a known attack campaign?

Yes — @posthog/siphash is associated with the GHSA-2jjg-c6pv-mwm3 campaign. Packages in the same campaign often share infrastructure and payloads, so check whether any related packages are also in your dependency tree.

How do I find @posthog/siphash across my projects, lockfiles, and CI pipelines?

Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for @posthog/siphash (version 1.1.2). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging @posthog/siphash across your stack and pipelines.

Malicious package

@posthog/siphashnpm

Malicious code in @posthog/siphash (npm) Remove it immediately and rotate any exposed credentials.

MAL-2025-190753

Immediate action

Remove the package, then rotate any secrets the build/runtime could reach.

npm uninstall @posthog/siphash

What this malware does

The package @posthog/siphash 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

1.1.2

Indicators of compromise (SHA-256)

ed632d6b4db6b2f74973167d160350198cd9130da004e958f2f1d51d217e9c3c

06113daabd3bc99b8cdcc1c4641266cebd61a5f0f10df264b2f37c955a121c20

666ec9d6c23bcebd76586f85c752bf2ea7826bf680b456e697127095d2472b63

c7726f58122df84c6d4a10a60244ab59013394e552e73f2849a7473a1325d280

Detection & response playbook

Credential / info stealer

Find it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for @posthog/siphash (version 1.1.2). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging @posthog/siphash across your stack and pipelines.
If you installed it — respond
@posthog/siphash 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.
Did it already run?
If @posthog/siphash was ever installed, its post-install/runtime payload may have already executed. O3's L7 egress monitoring and runtime eBPF sensors detect the credential exfiltration or command-and-control callback after install and block the malicious outbound channel, so you catch and contain the actual compromise — not just the presence of the package.
How O3 protects you
O3 blocks @posthog/siphash before install through its supply-chain scanner, and if it has already run, detects and severs the exfiltration or C2 callback at runtime through L7 egress monitoring and eBPF.

Frequently asked questions

No. @posthog/siphash on npm has been identified as a malicious package (version 1.1.2 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

GHSA-2jjg-c6pv-mwm3

References

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks @posthog/siphash-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