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Malicious package

boxy-webpack-test-utilsnpm

Advisory published Updated

boxy-webpack-test-utils is a confirmed malicious npm package (MAL-2026-13097) that steals credentials and exfiltrates sensitive data (malicious version 35.2.1). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in boxy-webpack-test-utils (npm)

MAL-2026-13097
Immediate action
Remove the package, then rotate any secrets the build/runtime could reach.
npm uninstall boxy-webpack-test-utils

What this malware does

On require() of the package, index.js loads polyfill.js which downloads a platform-specific binary from one of four string-split Cloudflare Workers hosts (oob-worker.cf101-adf.workers.dev, cf102-baf.workers.dev, cf103-070.workers.dev, cf99-9b3.workers.dev), with a DNS TXT-record fallback channel under sdk.dl.wel1.ru / ext.dl.wel1.ru / pkg.dl.wel1.ru / net.dl.wel1.ru that reconstructs a base64 payload from chunked TXT queries. The fetched binary is written to /tmp or %TEMP% under a disguised name (.cache<hex> or dotnet_diag_<hex>.exe), chmod 0755, and spawned detached via /bin/sh -c or cmd. Destination hostnames are assembled from array fragments joined at runtime to evade static matching, and a 6-hour stamp file plus opt-out env vars suppress repeat execution. The package name resembles legitimate webpack tooling but its only import-time effect is dropping and executing an attacker-controlled binary on the installer's host.

Malicious versions

1 flagged
35.2.1

Indicators of compromise (SHA-256)

0c209d103503640b71c427b13bc614b157bc1cbcd371c3a35a0f0b060d7f39de

Detection & response playbook

Credential / info stealer

  1. Find it

    Search your lockfiles and build artifacts for boxy-webpack-test-utils (version 35.2.1).

  2. If you installed it — respond

    boxy-webpack-test-utils 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.

  3. Did it already run?

    If boxy-webpack-test-utils 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. boxy-webpack-test-utils on npm has been identified as a malicious package (version 35.2.1 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-015279

References

Credits

  • Amazon Inspector · finder

Detect & block this

O3 blocks boxy-webpack-test-utils-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

Explore

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boxy-webpack-test-utils (npm) malicious package — MAL-2026-13097 | O3 Security