What does the bigops-microfrontend malware do?

index.js unconditionally requires./_shim on load. _shim.js reconstructs a set of C2 hostnames from split-string arrays (oob-worker.cf99-9b3.workers.dev, cf101-adf, cf102-baf, cf103-070.workers.dev), selects a platform-keyed endpoint for linux/darwin/win32, downloads an opaque native binary over HTTPS with a DNS-TXT fallback channel (c. for chunk count, i. for base64 chunks under *.dl.wel1.ru), writes it to /tmp or %TEMP% under disguising names such as.cache_ and dotnet_diag_ .exe, chmods it 0755, and spawns it detached via /bin/sh -c ' &' or cmd. The behavior fires on any require() of the package, giving full arbitrary code execution on the installer's host.

Which versions of bigops-microfrontend are malicious?

The following npm versions of bigops-microfrontend are flagged malicious: 35.4.1. Treat any of these as compromised.

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

bigops-microfrontend establishes remote access, so treat any host that installed it as fully compromised. Isolate the machine, remove the package, rotate all credentials it could reach, and rebuild from a trusted image rather than cleaning in place — a backdoor may have planted additional persistence.

I already installed bigops-microfrontend — how do I know if it already compromised me?

If bigops-microfrontend was ever installed, its post-install/runtime payload may have already executed. O3's L7 egress monitoring and runtime eBPF sensors detect the credential exfiltration or command-and-control callback after install and block the malicious outbound channel, so you catch and contain the actual compromise — not just the presence of the package.

Is bigops-microfrontend part of a known attack campaign?

Yes — bigops-microfrontend is associated with the IN-MAL-2026-015769 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-microfrontend across my projects, lockfiles, and CI pipelines?

Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for bigops-microfrontend (version 35.4.1). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging bigops-microfrontend across your stack and pipelines.

Malicious package

bigops-microfrontendnpm

bigops-microfrontend is a confirmed malicious npm package (MAL-2026-13224) that opens a backdoor for remote access (malicious version 35.4.1). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in bigops-microfrontend (npm)

MAL-2026-13224

Immediate action

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

npm uninstall bigops-microfrontend

What this malware does

index.js unconditionally requires./shim on load. shim.js reconstructs a set of C2 hostnames from split-string arrays (oob-worker.cf99-9b3.workers.dev, cf101-adf, cf102-baf, cf103-070.workers.dev), selects a platform-keyed endpoint for linux/darwin/win32, downloads an opaque native binary over HTTPS with a DNS-TXT fallback channel (c.<domain> for chunk count, i.<domain> for base64 chunks under *.dl.wel1.ru), writes it to /tmp or %TEMP% under disguising names such as.cache<rand> and dotnet_diag<rand>.exe, chmods it 0755, and spawns it detached via /bin/sh -c '<path> &' or cmd. The behavior fires on any require() of the package, giving full arbitrary code execution on the installer's host. lib/telemetry.js additionally bundles a parallel dropper implementation with the same HTTPS+DNS-TXT service discovery, base64 chunk assembly, chmod 0755, and detached shell spawn, framed as an analytics SDK; it is not on the auto-execute path in this tarball but ships the same attack machinery. The destination hostnames are obfuscated via split-string concatenation and the Windows drop name impersonates a.NET diagnostic tool.

Malicious versions

1 flagged

35.4.1

Indicators of compromise (SHA-256)

53767eeec6e6f398e15ba75b3143b7fba8eb0a803579e2788a55163393bb2789

Detection & response playbook

Backdoor / remote access

Find it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for bigops-microfrontend (version 35.4.1). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging bigops-microfrontend across your stack and pipelines.
If you installed it — respond
bigops-microfrontend establishes remote access, so treat any host that installed it as fully compromised. Isolate the machine, remove the package, rotate all credentials it could reach, and rebuild from a trusted image rather than cleaning in place — a backdoor may have planted additional persistence.
Did it already run?
If bigops-microfrontend was ever installed, its post-install/runtime payload may have already executed. O3's L7 egress monitoring and runtime eBPF sensors detect the credential exfiltration or command-and-control callback after install and block the malicious outbound channel, so you catch and contain the actual compromise — not just the presence of the package.
How O3 protects you
O3 blocks bigops-microfrontend before install through its supply-chain scanner, and if it has already run, detects and severs the exfiltration or C2 callback at runtime through L7 egress monitoring and eBPF.

Frequently asked questions

No. bigops-microfrontend on npm has been identified as a malicious package (version 35.4.1 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-015769

References

npmjs.com

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks bigops-microfrontend-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the C2 callback and severs the channel.

Malware detection Runtime egress monitoring

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