Which versions of f0-data-constructor are malicious?

The following npm versions of f0-data-constructor are flagged malicious: 1.0.0, 28.0.0. Treat any of these as compromised.

How do I remediate f0-data-constructor if I installed it?

f0-data-constructor 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 f0-data-constructor — how do I know if it already compromised me?

If f0-data-constructor 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 f0-data-constructor part of a known attack campaign?

Yes — f0-data-constructor is associated with the GHSA-42r3-x9wh-9q73, IN-MAL-2026-011137 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 f0-data-constructor 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 f0-data-constructor (2 malicious versions). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging f0-data-constructor across your stack and pipelines.

Malicious package

f0-data-constructornpm

f0-data-constructor is a confirmed malicious npm package (MAL-2023-1491) that opens a backdoor for remote access (malicious versions 1.0.0, 28.0.0). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in f0-data-constructor (npm)

MAL-2023-1491

Immediate action

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

npm uninstall f0-data-constructor

What this malware does

The package's preinstall hook auto-executes index.js on npm install. The script imports https and os, collects os.hostname(), os.platform(), os.arch(), os.homedir(), and dns.getServers(), and POSTs the JSON payload to the hardcoded host rb6etzw0lznpijvfl5m5ujmyrpxhl99y.oastify.com at path /hit. oastify.com is Burp Collaborator out-of-band infrastructure; the subdomain uniquely identifies the operator's Collaborator session. The behavior matches a dependency-confusion / typosquat reconnaissance beacon: no documented package purpose, no consent, and the collected fields exist solely to identify the installer host to the operator.

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.

The OpenSSF Package Analysis project identified 'f0-data-constructor' @ 28.0.0 (npm) as malicious.

It is considered malicious because:

The package communicates with a domain associated with malicious activity.

Malicious versions

2 flagged

1.0.028.0.0

Indicators of compromise (SHA-256)

9133720bff10d051149c2acb0dcab98768e9badae42fe211352aa258afd49c28

203b615a64203063f94994f1dbe5118a11c9543bfc3f4d47322f54aabb61f814

ce363be4d04420ff3e74a29fbcb5807cde29ca45f3e1dfd2b2e1c2aaa35b6c41

23fc7101aab5c7172a2ab40e0e1ce62dbd251d5301f5efb5f4c30cab065bb5cd

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 f0-data-constructor (2 malicious versions). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging f0-data-constructor across your stack and pipelines.
If you installed it — respond
f0-data-constructor 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 f0-data-constructor 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 f0-data-constructor 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. f0-data-constructor on npm has been identified as a malicious package (versions 1.0.0, 28.0.0 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

GHSA-42r3-x9wh-9q73IN-MAL-2026-011137

References

Credits

Amazon Inspector · finder
OpenSSF: Package Analysis · finder

Detect & block this

O3 blocks f0-data-constructor-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

Explore

All malware advisories How O3 detects malware Vulnerability database