The devplatform-spa-plugin-s3-module-loader npm package version 35.8.2 includes malicious code that, when loaded, fetches platform-specific payloads from obfuscated Cloudflare Workers URLs. These payloads are assembled at runtime from split string arrays, saved as hidden temporary files (dot-files on Unix, dotnet_diag_*.exe on Windows), permissioned to be executable, and then spawned detached via shell commands. If HTTPS delivery is blocked, the payload is reconstructed from base64-encoded DNS TXT records from attacker-controlled domains. The entire payload delivery mechanism is author-controlled and obfuscated, with cover identifiers to disguise telemetry activity. This behavior is unrelated to the package's advertised functionality as an S3 module loader.

This malicious package can execute arbitrary code on the host system where it is installed, potentially leading to full system compromise, data theft, or further malware deployment. The payload delivery is stealthy and obfuscated, increasing the risk of undetected compromise. Since the payload is fully controlled by the attacker and can be dynamically fetched or reconstructed, the impact can vary widely depending on the attacker's intent.

No official patch or remediation is currently documented. Users should immediately remove the affected version (=35.8.2) of devplatform-spa-plugin-s3-module-loader from their environments. Avoid installing or using this package version. Monitor for any unexpected network connections to the described Cloudflare Workers hosts or suspicious DNS TXT queries. Check vendor advisories or trusted security sources for updates or official fixes. Consider using trusted package sources and scanning dependencies for malicious code before deployment.