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OpenAdvisories
Malicious MAL-2026-14031

datefmt-core-utils

npm package · versions 1.0.0

Reported Aug 14, 2026 · Updated Aug 14, 2026

If this package is installed

Remove it, treat the machine (or CI runner) as compromised, and rotate every secret, token and key it could access — from a different, clean machine.

Details

Source: amazon-inspector (360a94a10ce13edded9e4a99c7c01de1ebfdd73a9af4ec49260f2cec165a609b)
The package advertises itself as a date-formatting utility but ships a postinstall.js that npm auto-executes on install via scripts.postinstall. postinstall.js opens a TCP connection to the hardcoded remote 8.135.48.40:4444 and wires /bin/bash stdio to that socket, giving the remote endpoint an interactive shell on the installer's machine. Three redundant methods are attempted (python3 pty.spawn, python3 subprocess, and Node net+child_process.spawn of '/bin/bash -i'). The index.js date-formatting code is a cover story unrelated to the postinstall payload.