Which versions of fpjson-lang are malicious?

The following npm versions of fpjson-lang are flagged malicious: 0.1.7. Treat any of these as compromised.

How do I remediate fpjson-lang if I installed it?

fpjson-lang 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.

I already installed fpjson-lang — how do I know if it already compromised me?

If fpjson-lang 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 fpjson-lang part of a known attack campaign?

Yes — fpjson-lang is associated with the IN-MAL-2026-004819 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 fpjson-lang 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 fpjson-lang (version 0.1.7). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging fpjson-lang across your stack and pipelines.

Malicious package

fpjson-langnpm

Malicious code in fpjson-lang (npm) Remove it immediately and rotate any exposed credentials.

MAL-2026-4566

Immediate action

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

npm uninstall fpjson-lang

What this malware does

package.json declares "preinstall": "./bin/install-deps", causing npm to execute a ~954KB packed Linux ELF binary on every install. The package advertises itself as a tiny JSON-based functional language built on Ramda, and the actual library at dist/cjs/index.js is ~1.8KB of pure JavaScript with no native dependency — there is no legitimate reason for a native install helper. Strings extracted from the shipped binary include HTTP/1.1, POST/DELETE verbs, GitHub API version 2022-11-28, USERPROFILE, TLS/crypto primitives (RSA_PKCS1_, Ed25519), PTRACE, and LIBBPF_0.0 — a feature set (HTTP client + GitHub API + ptrace + crypto) wholly unrelated to a JSON parser. The binary is packed and opaque to static review. The combination of (a) auto-execution at install time via preinstall, (b) shipped opaque native binary, (c) capability set entirely unrelated to the package's declared purpose, and (d) absent source/build manifest matches the install-time dropper pattern: arbitrary attacker-controlled code runs on every installer's machine on npm install.

This package was compromised as part of the IronWorm campaign. This campaign executes a malicious binary payload during installation via a preinstall hook. The payload is a Rust-built infostealer that targets developer environments, scanning for and harvesting credentials related to cloud providers, object storage, databases, source-control, package registries, and AI developer tools. It also targets cryptocurrency wallets, specifically injecting a malicious JavaScript hook into the Exodus desktop wallet to capture passwords and recovery phrases. Furthermore, the malware exhibits worm-like behavior by stealing GitHub and NPM credentials to push malicious updates to the victim's repositories and publish trojanized packages, and it uses an eBPF-based kernel rootkit to hide its processes and network connections on Linux systems.

Malicious versions

1 flagged

0.1.7

Indicators of compromise (SHA-256)

38aca097f261c15ef9901f259883679e2d4308d6e4053099643c8befe9a14318

146faaf0d97c6a533a969bc3f3f117811f9317dc865ed4ab37f1679842ddeaae

Detection & response playbook

Credential / info stealer

Find it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for fpjson-lang (version 0.1.7). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging fpjson-lang across your stack and pipelines.
If you installed it — respond
fpjson-lang 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 fpjson-lang 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 fpjson-lang 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. fpjson-lang on npm has been identified as a malicious package (version 0.1.7 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-004819

References

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks fpjson-lang-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the credential exfiltration and severs the channel.

Malware detection Runtime egress monitoring