Which versions of core-js-gnz are malicious?

The following npm versions of core-js-gnz are flagged malicious: 1.0.0. Treat any of these as compromised.

How do I remediate core-js-gnz if I installed it?

Remove core-js-gnz from your project and lockfile, then assume any secrets accessible to the build or runtime were exposed: rotate API keys, tokens, and credentials, and audit for unexpected outbound activity or persistence.

I already installed core-js-gnz — how do I know if it already compromised me?

If core-js-gnz 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.

Is core-js-gnz part of a known attack campaign?

Yes — core-js-gnz is associated with the IN-MAL-2026-020892 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 core-js-gnz across my projects, lockfiles, and CI pipelines?

Search your lockfiles and build artifacts for core-js-gnz (version 1.0.0).

Malicious package

core-js-gnznpm

Advisory published Oct 4, 2026Updated Oct 4, 2026

core-js-gnz is a confirmed malicious npm package (MAL-2026-17474) that executes malicious code on install (malicious version 1.0.0). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in core-js-gnz (npm)

MAL-2026-17474

Immediate action

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

npm uninstall core-js-gnz

What this malware does

On install, package.json runs node init.js as a postinstall hook. init.js collects host identifiers (os.hostname(), os.userInfo().username, os.platform(), os.arch(), node version, OS release) and POSTs them to https://helper.businesse-vip1.workers.dev/report, then fetches an AES-256-GCM encrypted blob from the /e endpoint on the same host (with TLS verification disabled via rejectUnauthorized:false), decrypts it in-process, writes the decoded content to the user cache directory as exec_runtime.py, and spawns a detached python3 process to execute it (stdio:'ignore', windowsHide, detached:true). Execution is gated on developer-machine heuristics (presence of Desktop/Documents/Downloads in the home directory) and rate-limited via a hidden ~/.cache/core-js-buffer/.init_check marker, with cover-story identifiers ('Environment check', 'TelemetrySender', a BIP-174 seed label). The package name and README advertise an unrelated hex-buffer utility, which does not match the observed behavior.

Malicious versions

1 flagged

1.0.0

Indicators of compromise (SHA-256)

dc57686b95f827f2c3b0501d97b6575e077247255bf5d4227ae9bc8bedd43937

Detection & response playbook

Malicious package

Find it
Search your lockfiles and build artifacts for core-js-gnz (version 1.0.0).
If you installed it — respond
Remove core-js-gnz from your project and lockfile, then assume any secrets accessible to the build or runtime were exposed: rotate API keys, tokens, and credentials, and audit for unexpected outbound activity or persistence.
Did it already run?
If core-js-gnz 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. core-js-gnz on npm has been identified as a malicious package (version 1.0.0 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-020892

References

npmjs.com

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks core-js-gnz-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the malicious outbound activity and severs the channel.

Malware detection Runtime egress monitoring

Explore

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