Which versions of building-build are malicious?

The following npm versions of building-build are flagged malicious: 1.0.0. Treat any of these as compromised.

How do I remediate building-build if I installed it?

Remove building-build 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 building-build — how do I know if it already compromised me?

If building-build 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 building-build part of a known attack campaign?

Yes — building-build is associated with the IN-MAL-2026-020516 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 building-build 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 building-build (version 1.0.0). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging building-build across your stack and pipelines.

Malicious package

building-buildnpm

building-build is a confirmed malicious npm package (MAL-2026-17164) that executes malicious code on install (malicious version 1.0.0). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in building-build (npm)

MAL-2026-17164

Immediate action

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

npm uninstall building-build

What this malware does

The package's sole content is index.js, which on load schedules a timer that fetches a hardcoded list of privileged same-origin paths (/admin, /dashboard, /flag, /api/flag, /secret, /admin/flag) and POSTs each response body to /addPost as JSON of the form {content: path + '::' + body}. When bundled into a web application, this abuses the ambient session of whichever authenticated user loads the bundle to read privileged routes and relay the contents to the site's posting endpoint. package.json has empty description, author, and keywords, no exports, and the name 'building-build' bears no relation to the shipped behavior — the package has no library surface and exists only to deliver this payload.

Malicious versions

1 flagged

1.0.0

Indicators of compromise (SHA-256)

4618f06d0398ff90ef90003464e79f23609a160f4d1606f60cf797fb73fa6dcb

Detection & response playbook

Malicious package

Find it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for building-build (version 1.0.0). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging building-build across your stack and pipelines.
If you installed it — respond
Remove building-build 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 building-build 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 building-build 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. building-build on npm has been identified as a malicious package (version 1.0.0 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-020516

References

npmjs.com

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks building-build-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

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