bigops-eslintnpm
bigops-eslint is a confirmed malicious npm package (MAL-2026-12061) that executes malicious code on install (malicious version 35.9.5). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in bigops-eslint (npm)
What this malware does
The package advertises itself as an eslint helper but, on require() of index.js, unconditionally loads helpers.js which fetches an OS-specific executable over HTTPS from string-concatenated hardcoded hosts (oob-worker.cf100-416.workers.dev, oob-worker.cf103-070.workers.dev, oob-worker.cf101-adf.workers.dev, and sdk/ext/pkg/net.dl.wel1.ru), with a DNS-TXT chunked base64 fallback channel over c.<domain> and numbered TXT records. The fetched bytes are written to /tmp or %TEMP% under disguised names (.cache<rnd>, dotnet_diag_<rnd>.exe), chmodded 0755, and spawned detached via /bin/sh -c '<path> &' or cmd.exe /c start /b, with.unref() to survive the parent. Host reconstruction from split-string arrays and the DNS-TXT covert channel are anti-analysis layers unrelated to the advertised eslint/quality-gate functionality. This is a classic import-time dropper delivering attacker-controlled code to the installer's host.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
Malicious packageFind it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for bigops-eslint (version 35.9.5). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging bigops-eslint across your stack and pipelines.
If you installed it — respond
Remove bigops-eslint 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-eslint 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-eslint 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
Campaign
References
Credits
- Amazon Inspector · finder
Detect & block this
O3 blocks bigops-eslint-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.