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Malicious package

routecraftnpm

Advisory published Updated

routecraft is a confirmed malicious npm package (MAL-2026-6229) that executes malicious code on install (malicious versions 4.2.0, 5.0.0). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in routecraft (npm)

MAL-2026-6229
Immediate action
Remove the package, then rotate any secrets the build/runtime could reach.
npm uninstall routecraft

What this malware does

[email protected] ships verbatim Express.js source (lib/routecraft.js, lib/application.js, lib/request.js, lib/response.js, lib/utils.js, lib/view.js — same layout, comments, and exports including createApplication, Router, and json/raw/text/urlencoded/static middleware) under a different package name and author with no Express attribution, presenting itself as an original 'lightweight HTTP routing framework'. package.json declares "preinstall": "node./lib/configure.js". lib/configure.js performs no compilation despite logging '...Skipping native addon compilation' — the package ships no native sources (no binding.gyp, no.cc/.cpp/.rs files). Instead, lines 10-12 contain if (os.platform() === 'win32' && v >= 18) { require('procwire'); }, conditionally loading the obscure procwire dependency (declared as ^1.3.0) only on Windows with Node >= 18. The false cover story, the platform gate, and the delegation of the executed code to an unpinned transitive dependency together form the standard pattern for shifting a malicious payload off the parent package so it appears clean while installers on Windows execute whatever procwire ships at install time.

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

2 flagged
4.2.05.0.0

Indicators of compromise (SHA-256)

35254023a0071db579346eebe9f0e355a847a6d7f4320f600354c220f00ba646
a0c4f17a9e94ab9fdbab7325f597551a6c0ba5b9e210cb0b7e28d3b86b4766d0
1d59be835e0f7c6030e248343fc25d7d5044225a02c021b588faa736bf204170
c9b8b5fd2b46134e9afdda559e336b7895f1c727d241c493fc93ae4e6b2d4875

Detection & response playbook

Malicious package
  1. Find it

    Search your lockfiles and build artifacts for routecraft (2 malicious versions).

  2. If you installed it — respond

    Remove routecraft 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.

  3. Did it already run?

    If routecraft 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. routecraft on npm has been identified as a malicious package (versions 4.2.0, 5.0.0 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-007085IN-MAL-2026-007086GHSA-mw8m-x3ph-h3x7RLMA-2026-05608

References

Credits

  • Amazon Inspector · finder
  • ReversingLabs · finder

Detect & block this

O3 blocks routecraft-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

routecraft (npm) malicious package — MAL-2026-6229 | O3 Security