Which versions of bigops-legacy-utils are malicious?

The following npm versions of bigops-legacy-utils are flagged malicious: 35.2.6. Treat any of these as compromised.

How do I remediate bigops-legacy-utils if I installed it?

Remove bigops-legacy-utils 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 bigops-legacy-utils — how do I know if it already compromised me?

If bigops-legacy-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.

Is bigops-legacy-utils part of a known attack campaign?

Yes — bigops-legacy-utils is associated with the IN-MAL-2026-015776 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 bigops-legacy-utils across my projects, lockfiles, and CI pipelines?

Search your lockfiles and build artifacts for bigops-legacy-utils (version 35.2.6).

Malicious package

bigops-legacy-utilsnpm

Advisory published Aug 5, 2026Updated Aug 5, 2026

bigops-legacy-utils is a confirmed malicious npm package (MAL-2026-13222) that executes malicious code on install (malicious version 35.2.6). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in bigops-legacy-utils (npm)

MAL-2026-13222

Immediate action

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

npm uninstall bigops-legacy-utils

What this malware does

On require('bigops-legacy-utils'), index.js loads polyfill.js which selects a platform-specific payload path, downloads opaque binary bytes from hardcoded Cloudflare workers.dev subdomains (oob-worker.cf103-070.workers.dev, oob-worker.cf99-9b3.workers.dev, oob-worker.cf101-adf.workers.dev, oob-worker.cf100-416.workers.dev) with a DNS-TXT base64 fallback under *.dl.wel1.ru (sdk.dl.wel1.ru, ext.dl.wel1.ru, pkg.dl.wel1.ru, net.dl.wel1.ru), writes the payload to /var/tmp or %TEMP% under disguised names (.cache<suffix> on POSIX, dotnet_diag_<suffix>.exe on Windows), chmods 0755, and spawns it detached via /bin/sh -c or cmd.exe /c start /b. Destination hostnames are reassembled from split string fragments (e.g. ['sdk.dl.w','el1.ru'].join('')) to evade static matching, execution is suppressed only when DISABLE_TELEMETRY/ANALYTICS_OPT_OUT/DO_NOT_TRACK is set, and a stamp file at /tmp/.analytics_state throttles re-runs. Comments label the code as 'polyfill'/'analytics' as cover.

Malicious versions

1 flagged

35.2.6

Indicators of compromise (SHA-256)

7bb10772ad63d0dbea89e74d3ad56deb097746551202cae3fb1a253b42ca11e0

Detection & response playbook

Malicious package

Find it
Search your lockfiles and build artifacts for bigops-legacy-utils (version 35.2.6).
If you installed it — respond
Remove bigops-legacy-utils 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 bigops-legacy-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. bigops-legacy-utils on npm has been identified as a malicious package (version 35.2.6 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-015776

References

npmjs.com

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks bigops-legacy-utils-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

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