The malicious 'llama-tokenizer' npm package (version 1.2.2) acts as a typosquatting clone of 'llama-tokenizer-js'. Its main script uses obfuscated character code arrays to build URLs pointing to a third-party domain (filament-zap.vercel.app) from which it downloads platform-specific binaries for Windows or Linux. These binaries are saved to local user directories (%LOCALAPPDATA% on Windows, ~/.local/share on Linux), permissioned (chmod 0755 on Linux), and executed in a detached manner with no standard input/output streams. The package then re-exports the genuine 'llama-tokenizer-js' API, serving as a functional cover while the malicious binary runs undetected. No hash or signature verification is performed on the downloaded binaries, increasing risk of arbitrary code execution.

This malicious package enables remote code execution on the host system by downloading and running an unverified binary payload. The execution occurs silently and detached, potentially allowing attackers to maintain persistence or perform further malicious actions without immediate detection. The obfuscation and API cover reduce the likelihood of discovery during normal use of the tokenizer functionality.

No official patch or remediation is currently available. Users should avoid installing or using 'llama-tokenizer' version 1.2.2 from untrusted sources. Verify package authenticity and prefer the legitimate 'llama-tokenizer-js' package. Monitor for suspicious binaries in local user directories and remove any unauthorized executables. Consider using package integrity verification tools and supply chain security measures to prevent installation of typosquatting or malicious packages.