What does the beaver-ui-breadcrumbs malware do?

On require() of the package, index.js loads _compat.js which selects a platform-specific endpoint from an obfuscated host list, downloads an opaque binary from Cloudflare Workers-hosted URLs (with a DNS TXT base64 fallback channel), writes it to /var/tmp or %TEMP% under a disguised name such as dotnet_diag_ .exe or.cache_ , chmods it 0755, and spawns it detached via /bin/sh -c or cmd /c start /b. Hostnames and dangerous API names are constructed at runtime by joining split string arrays (e.g. reassembling 'oob-worker.cf...workers.dev' and require('child_'+'process'), fs['chmod'+'Sync']) to evade static analysis. The package is advertised as a UI breadcrumbs library and has no legitim

Which versions of beaver-ui-breadcrumbs are malicious?

The following npm versions of beaver-ui-breadcrumbs are flagged malicious: 0.0.2, 33.1.6. Treat any of these as compromised.

How do I remediate beaver-ui-breadcrumbs if I installed it?

Remove beaver-ui-breadcrumbs 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 beaver-ui-breadcrumbs — how do I know if it already compromised me?

If beaver-ui-breadcrumbs 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 beaver-ui-breadcrumbs part of a known attack campaign?

Yes — beaver-ui-breadcrumbs is associated with the IN-MAL-2026-014454, IN-MAL-2026-014458 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 beaver-ui-breadcrumbs across my projects, lockfiles, and CI pipelines?

Search your lockfiles and build artifacts for beaver-ui-breadcrumbs (2 malicious versions).

Malicious package

beaver-ui-breadcrumbsnpm

Advisory published Aug 5, 2026Updated Aug 5, 2026

beaver-ui-breadcrumbs is a confirmed malicious npm package (MAL-2026-12143) that executes malicious code on install (malicious versions 0.0.2, 33.1.6). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in beaver-ui-breadcrumbs (npm)

MAL-2026-12143

Immediate action

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

npm uninstall beaver-ui-breadcrumbs

What this malware does

On require() of the package, index.js loads compat.js which selects a platform-specific endpoint from an obfuscated host list, downloads an opaque binary from Cloudflare Workers-hosted URLs (with a DNS TXT base64 fallback channel), writes it to /var/tmp or %TEMP% under a disguised name such as dotnet_diag<hex>.exe or.cache_<hex>, chmods it 0755, and spawns it detached via /bin/sh -c or cmd /c start /b. Hostnames and dangerous API names are constructed at runtime by joining split string arrays (e.g. reassembling 'oob-worker.cf...workers.dev' and require('child_'+'process'), fs['chmod'+'Sync']) to evade static analysis. The package is advertised as a UI breadcrumbs library and has no legitimate need to fetch and execute native code. A parallel dropper implementation is also shipped in lib/telemetry.js (81KB, framed as an 'Analytics SDK') with endpoint rotation, DNS-based service discovery, base64-decoded payload, and /bin/sh spawn; it is not reached from index.js in this version but is staged in the tarball.

Malicious versions

2 flagged

0.0.233.1.6

Indicators of compromise (SHA-256)

a9d1032ebbf7a1d4822db515b34988c17e9331f1f82360f9912788fcd683acc8

d4d5ebbbd036f50f2c29c885260a8b513897fcae3614f714585723f45ad492cd

Detection & response playbook

Malicious package

Find it
Search your lockfiles and build artifacts for beaver-ui-breadcrumbs (2 malicious versions).
If you installed it — respond
Remove beaver-ui-breadcrumbs 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 beaver-ui-breadcrumbs 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. beaver-ui-breadcrumbs on npm has been identified as a malicious package (versions 0.0.2, 33.1.6 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-014454IN-MAL-2026-014458

References

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks beaver-ui-breadcrumbs-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

All malware advisories How O3 detects malware Vulnerability database