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Malicious package

a.poltoradnev-package-bnpm

Advisory published Updated

a.poltoradnev-package-b is a confirmed malicious npm package (MAL-2026-12126) that executes malicious code on install (malicious versions 0.0.2, 33.9.1). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in a.poltoradnev-package-b (npm)

MAL-2026-12126
Immediate action
Remove the package, then rotate any secrets the build/runtime could reach.
npm uninstall a.poltoradnev-package-b

What this malware does

On require() of the package, index.js loads bridge.js which selects a platform-specific output path, fetches an opaque binary over HTTPS from Cloudflare Workers hosts whose names are assembled from split string fragments (oob-worker.cf100-4.16.workers.dev, oob-worker.cf103-070.workers.dev, oob-worker.cf101-adf.workers.dev), writes it to /var/tmp/.cache<hex> on Unix or %TEMP%\dotnet_diag_<hex>.exe on Windows, chmods 0755, and spawns it detached via /bin/sh -c or cmd. A DNS-TXT fallback channel reconstructs a base64 payload from numbered subdomains under tin.dl.well1.site, tina.dl.well1.site, ldr.dl.well1.site, and win.dl.well1.site when the HTTPS fetch fails. Destination hostnames are constructed at runtime via Array.join on split fragments to evade static analysis. The written binary is unpinned, unsigned, and unverified, and the code path fires as an import-time side effect rather than through any explicit user action; cover-story identifiers (analytics_state, dotnet_diag_, a DISABLE_TELEMETRY gate) do not correspond to installer-configured behavior.

Malicious versions

2 flagged
0.0.233.9.1

Indicators of compromise (SHA-256)

8a49533ddaeb856979ea3ed058fcb5955d6b20c2e5711401b597c2369e544d40
ebe5bbc564bb1c441ce12acaf4d177fabcd3fe5963f3c870119ee1519abab675

Detection & response playbook

Malicious package

  1. Find it

    Search your lockfiles and build artifacts for a.poltoradnev-package-b (2 malicious versions).

  2. If you installed it — respond

    Remove a.poltoradnev-package-b 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 a.poltoradnev-package-b 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. a.poltoradnev-package-b on npm has been identified as a malicious package (versions 0.0.2, 33.9.1 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-014583IN-MAL-2026-014581

References

Credits

  • Amazon Inspector · finder

Detect & block this

O3 blocks a.poltoradnev-package-b-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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a.poltoradnev-package-b (npm) malicious package — MAL-2026-12126 | O3 Security