Which versions of jan-browser are malicious?

The following npm versions of jan-browser are flagged malicious: 0.13.1. Treat any of these as compromised.

How do I remediate jan-browser if I installed it?

jan-browser 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 jan-browser — how do I know if it already compromised me?

If jan-browser 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 jan-browser part of a known attack campaign?

Yes — jan-browser is associated with the GHSA-6jqc-mw3x-g53g 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 jan-browser 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 jan-browser (version 0.13.1). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging jan-browser across your stack and pipelines.

Malicious package

jan-browsernpm

Malicious code in jan-browser (npm) Remove it immediately and rotate any exposed credentials.

MAL-2025-190847

Immediate action

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

npm uninstall jan-browser

What this malware does

The package jan-browser 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

0.13.1

Indicators of compromise (SHA-256)

a3954e4e8e77c870bfc41cd61410400a2f7ba85ce1d56123f2e672f63543e6e1

6061d20158eb6f2952932cac8bd818201360f36f2a4fd989357c12400c58a49b

88d7b60d0a0cd9cf4a6e4981157939e3616f0d02c953c60130dc759637bac5b6

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 jan-browser (version 0.13.1). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging jan-browser across your stack and pipelines.
If you installed it — respond
jan-browser 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 jan-browser 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 jan-browser 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. jan-browser on npm has been identified as a malicious package (version 0.13.1 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

GHSA-6jqc-mw3x-g53g

References

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks jan-browser-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