What does the fdir4 malware do?

The package fdir4 was found to contain malicious code. The OpenSSF Package Analysis project identified 'fdir4' @ 99.99.2 (npm) as malicious. It is considered malicious because: - The package communicates with a domain associated with malicious activity. - The package executes one or more commands associated with malicious behavior.

Which versions of fdir4 are malicious?

The following npm versions of fdir4 are flagged malicious: 99.99.2. Treat any of these as compromised.

How do I remediate fdir4 if I installed it?

Remove fdir4 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 fdir4 — how do I know if it already compromised me?

If fdir4 was installed, its post-install payload may already have run. Removing the package does not undo that — check outbound connections and credential use from the install window onward.

How do I find fdir4 across my projects, lockfiles, and CI pipelines?

Search your lockfiles and build artifacts for fdir4 (version 99.99.2).

Malicious package

fdir4npm

Advisory published Dec 6, 2025Updated Dec 10, 2025

fdir4 is a confirmed malicious npm package (MAL-2025-192355) that executes malicious code on install (malicious version 99.99.2). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in fdir4 (npm)

MAL-2025-192355

Immediate action

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

npm uninstall fdir4

What this malware does

The package fdir4 was found to contain malicious code.

The OpenSSF Package Analysis project identified 'fdir4' @ 99.99.2 (npm) as malicious.

It is considered malicious because:

The package communicates with a domain associated with malicious activity.
The package executes one or more commands associated with malicious behavior.

Malicious versions

1 flagged

99.99.2

Indicators of compromise (SHA-256)

2864053a37838b568ec7f045df7742f31a81c95af5bf06a5684c8b1361a213b7

64821a4790ad9d467b84b11aa1c7038cfa1d2c7307e7db03f049a76104c15850

Detection & response playbook

Malicious package

Find it
Search your lockfiles and build artifacts for fdir4 (version 99.99.2).
If you installed it — respond
Remove fdir4 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 fdir4 was installed, its post-install payload may already have run. Removing the package does not undo that — check outbound connections and credential use from the install window onward.

Frequently asked questions

No. fdir4 on npm has been identified as a malicious package (version 99.99.2 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Credits

Amazon Inspector · finder
OpenSSF: Package Analysis · finder

Detect & block this

O3 blocks fdir4-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

Explore

All malware advisories How O3 detects malware Vulnerability database