The npm package fpjson-lang version 0.1.7 contains a malicious preinstall script that executes a packed Linux ELF binary during installation. This binary is unrelated to the package's declared functionality and includes capabilities such as HTTP client, GitHub API interaction, ptrace, cryptographic operations, and an eBPF-based kernel rootkit. The malware is part of the IronWorm campaign and acts as an infostealer targeting developer credentials, cloud services, cryptocurrency wallets, and exhibits worm-like behavior to propagate by pushing malicious updates to repositories. Removal of the package does not guarantee full remediation due to potential system compromise.