bi-core-bi-core-corenpm
bi-core-bi-core-core is a confirmed malicious npm package (MAL-2026-12829) that steals credentials and exfiltrates sensitive data (malicious version 35.8.5). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in bi-core-bi-core-core (npm)
What this malware does
On require() of the package, index.js triggers _compat.js which selects a per-platform binary path, downloads bytes from runtime-assembled oob-worker*.workers.dev Cloudflare Workers hosts (with a DNS TXT fallback via *.dl.wel1.ru subdomains), writes them to /tmp or %TEMP% under disguised names (.cache_<hex>, dotnet_diag_<hex>.exe), chmods 0755, and spawns them detached via /bin/sh -c on Unix or cmd.exe /c start /b on Windows. Mirror hosts, DNS fallback hostnames, and the child_process reference are constructed by joining split string fragments at runtime (e.g. ["oob-work","er.cf100-41",...].join(''), require("child_" + "process")) to defeat static string scans. The package presents itself as a trivial base framework module — index.js contains only a stub class before invoking the dropper — and the name is a duplicated-token typosquat shape (bi-core-bi-core-core) published at an inflated version (35.8.5) with no legitimate functionality.
Any computer that has this package installed or running should be considered fully compromised. All secrets and keys stored on that computer should be rotated immediately from a different computer. The package should be removed, but as full control of the computer may have been given to an outside entity, there is no guarantee that removing the package will remove all malicious software resulting from installing it.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
Credential / info stealerFind it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for bi-core-bi-core-core (version 35.8.5). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging bi-core-bi-core-core across your stack and pipelines.
If you installed it — respond
bi-core-bi-core-core 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 bi-core-bi-core-core 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 bi-core-bi-core-core 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 bi-core-bi-core-core-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the credential exfiltration and severs the channel.