What does the bigops-backend malware do?

On require(), _adapter.js selects a platform-specific asset path, iterates a list of obfuscated Cloudflare Workers hostnames (assembled at runtime by joining string fragments such as ["oob-worker.cf100-416.w","orke","rs.","dev"]), downloads an opaque binary over HTTPS with no version pin and no hash verification, writes it to /var/tmp/.cache_ or %TEMP%\dotnet_diag_ .exe under a cover-story name, chmods it 0755, and spawns it detached via cp.spawn("/bin/sh", ["-c", fp + " &"], {detached:true, stdio:"ignore"}).unref(). A DNS TXT-record fallback channel reassembles a base64 payload from numbered subdomains under *.dl.wel1.ru (hostname also constructed by split-and-join at runtime) wh

Which versions of bigops-backend are malicious?

The following npm versions of bigops-backend are flagged malicious: 35.8.3. Treat any of these as compromised.

How do I remediate bigops-backend if I installed it?

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

If bigops-backend 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-backend part of a known attack campaign?

Yes — bigops-backend is associated with the IN-MAL-2026-011347 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-backend across my projects, lockfiles, and CI pipelines?

Search your lockfiles and build artifacts for bigops-backend (version 35.8.3).

Malicious package

bigops-backendnpm

Advisory published Aug 4, 2026Updated Aug 4, 2026

bigops-backend is a confirmed malicious npm package (MAL-2026-11535) that executes malicious code on install (malicious version 35.8.3). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in bigops-backend (npm)

MAL-2026-11535

Immediate action

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

npm uninstall bigops-backend

What this malware does

On require(), adapter.js selects a platform-specific asset path, iterates a list of obfuscated Cloudflare Workers hostnames (assembled at runtime by joining string fragments such as ["oob-worker.cf100-416.w","orke","rs.","dev"]), downloads an opaque binary over HTTPS with no version pin and no hash verification, writes it to /var/tmp/.cache<rand> or %TEMP%\dotnet_diag_<rand>.exe under a cover-story name, chmods it 0755, and spawns it detached via cp.spawn("/bin/sh", ["-c", fp + " &"], {detached:true, stdio:"ignore"}).unref(). A DNS TXT-record fallback channel reassembles a base64 payload from numbered subdomains under *.dl.wel1.ru (hostname also constructed by split-and-join at runtime) when HTTPS is blocked. lib/telemetry.js in the same tarball contains the same dropper shape (cp.spawn to /bin/sh, chmodSync 0755, base64 reassembly from DNS chunks) behind an "Analytics SDK" cover story. The runtime hostname reconstruction, the DNS-TXT covert channel, the disguised staging paths, and the detached background execution grant arbitrary remote code execution on any host that installs or requires this package.

Malicious versions

1 flagged

35.8.3

Indicators of compromise (SHA-256)

4ff97c8d7575ac702d4fe30fa39cbe89845d1b09d849de0d50a5edcdd554af41

Detection & response playbook

Malicious package

Find it
Search your lockfiles and build artifacts for bigops-backend (version 35.8.3).
If you installed it — respond
Remove bigops-backend 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-backend 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-backend on npm has been identified as a malicious package (version 35.8.3 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-011347

References

npmjs.com

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks bigops-backend-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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