What does the bigops-watchdog-worker malware do?

On require() of bigops-watchdog-worker, index.js loads _runtime.js which reconstructs remote hostnames from split-string fragments (e.g. joining ["oob-w","orker.cf102-baf.workers.d","ev"] and ['sdk.dl.wel1','.ru']), selects a URL keyed on process.platform/arch (linux_x64, linux_arm64, darwin, win32), downloads opaque binary bytes over HTTPS, writes them to /tmp/.cache_ on Unix or %TEMP%\dotnet_diag_ .exe on Windows (masquerading as a Microsoft diagnostic), chmods 0755, and spawns the binary detached via /bin/sh -c or cmd.exe. A DNS TXT chunked-record fallback reassembles a base64 payload if HTTPS fails. Anti-analysis features include a cache stamp at /tmp/.analytics_state that suppr

Which versions of bigops-watchdog-worker are malicious?

The following npm versions of bigops-watchdog-worker are flagged malicious: 35.7.4. Treat any of these as compromised.

How do I remediate bigops-watchdog-worker if I installed it?

bigops-watchdog-worker 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.

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

If bigops-watchdog-worker 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-watchdog-worker part of a known attack campaign?

Yes — bigops-watchdog-worker is associated with the IN-MAL-2026-015527 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-watchdog-worker 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-watchdog-worker (version 35.7.4). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging bigops-watchdog-worker across your stack and pipelines.

Malicious package

bigops-watchdog-workernpm

bigops-watchdog-worker is a confirmed malicious npm package (MAL-2026-12856) that steals credentials and exfiltrates sensitive data (malicious version 35.7.4). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in bigops-watchdog-worker (npm)

MAL-2026-12856

Immediate action

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

npm uninstall bigops-watchdog-worker

What this malware does

On require() of bigops-watchdog-worker, index.js loads runtime.js which reconstructs remote hostnames from split-string fragments (e.g. joining ["oob-w","orker.cf102-baf.workers.d","ev"] and ['sdk.dl.wel1','.ru']), selects a URL keyed on process.platform/arch (linux_x64, linux_arm64, darwin, win32), downloads opaque binary bytes over HTTPS, writes them to /tmp/.cache<uid> on Unix or %TEMP%\dotnet_diag_<uid>.exe on Windows (masquerading as a Microsoft diagnostic), chmods 0755, and spawns the binary detached via /bin/sh -c or cmd.exe. A DNS TXT chunked-record fallback reassembles a base64 payload if HTTPS fails. Anti-analysis features include a cache stamp at /tmp/.analytics_state that suppresses re-execution for ~23000 seconds and honors DISABLE_TELEMETRY/ANALYTICS_OPT_OUT/DO_NOT_TRACK env vars to appear benign under inspection. Neither oob-worker.*.workers.dev nor *.dl.wel1.ru is a publisher-controlled or publisher-adjacent host.

Malicious versions

1 flagged

35.7.4

Indicators of compromise (SHA-256)

a65df39f269239434211427140c77c096d41d8de8800667ef39a27bf89572c67

Detection & response playbook

Credential / info stealer

Find it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for bigops-watchdog-worker (version 35.7.4). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging bigops-watchdog-worker across your stack and pipelines.
If you installed it — respond
bigops-watchdog-worker 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.
Did it already run?
If bigops-watchdog-worker 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-watchdog-worker 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-watchdog-worker on npm has been identified as a malicious package (version 35.7.4 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-015527

References

npmjs.com

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks bigops-watchdog-worker-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

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