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Malicious package

m2fcsfyjkuxbnpm

Advisory published Updated

m2fcsfyjkuxb is a confirmed malicious npm package (MAL-2026-15605) that typosquats a legitimate package to trick installs (malicious version 1.0.0). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in m2fcsfyjkuxb (npm)

MAL-2026-15605
Immediate action
Remove the package, then rotate any secrets the build/runtime could reach.
npm uninstall m2fcsfyjkuxb

What this malware does

Published as part of a ClickFix-style fake-CAPTCHA phishing campaign documented by OX Security (see reference). The package's only file is index.html, declared as the npm "main" entry; package.json defines no preinstall/install/postinstall/prepare lifecycle script, so the payload does not execute at npm install time. index.html renders a fake Cloudflare Turnstile verification widget. An obfuscator.io-obfuscated inline script builds a hardcoded redirect URL to https://login.microsofte.live/ (a typosquat of a Microsoft sign-in domain), appends the visitor's original query-string parameters, and navigates the browser there via window.location.replace(). The package therefore does not attack the installing machine directly; it is used as a static file host on the npm CDN (e.g. unpkg/jsDelivr) so the index.html can be linked to and opened directly in a victim's browser as a phishing/ClickFix landing page. Published by npm user "johnvaldez9a" as part of a burst of near-identical single-purpose packages published between 2026-08-04 and 2026-08-24 that share this same fake-Turnstile-redirect page structure.

The package was found to contain malicious code or consuming dependency that contains 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.

Malicious versions

1 flagged
1.0.0

Indicators of compromise (SHA-256)

25b5eb444b26c42c357352ff4bdc8f6e1020eefa1ae50ac18872aabb5a67b75e
b821fc480bff44cb2f0cc6c1682a9d6a6b98d3874594d2392e37fc678734c1b1

Detection & response playbook

Typosquat
  1. Find it

    Search your lockfiles and build artifacts for m2fcsfyjkuxb (version 1.0.0).

  2. If you installed it — respond

    m2fcsfyjkuxb is a typosquat — you almost certainly intended a legitimately-named package. Remove m2fcsfyjkuxb, install the correct package, and rotate any secrets exposed during the install since post-install scripts may have already run.

  3. Did it already run?

    If m2fcsfyjkuxb 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. m2fcsfyjkuxb 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-2026-019279GHSA-7qc3-j6rw-97cj

References

Credits

  • Amazon Inspector · finder
  • OX Security · finder

Detect & block this

O3 blocks m2fcsfyjkuxb-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.

Explore

m2fcsfyjkuxb (npm) malicious package — MAL-2026-15605 | O3 Security