The npm package 'checkout-promocode-logic' version 35.7.7 contains malicious code that, upon requiring the module, loads a script which fetches and executes a payload from obfuscated remote hosts. The payload is downloaded via HTTPS or a DNS-TXT record covert channel, saved to temporary locations with names mimicking legitimate .NET diagnostic files, and executed to evade detection. The malicious code uses runtime string assembly to hide its network destinations, file names, and child process invocations, complicating analysis and detection.