MAL-2026-12721 Malicious code in devplatform-npm-versions-checker (npm)

On require of the package, adapter.js fetches a platform-specific binary from obfuscated Cloudflare Workers hosts (oob-worker.cf100-416.workers.dev, cf102-baf.workers.dev, cf99-9b3.workers.dev, cf103-070.workers.dev) whose hostnames are hidden via […].join('') string-splitting, with a DNS-TXT fallback channel that reassembles a base64 payload from numbered TXT records under *.dl.wel1.ru (sdk./ext./pkg./net.dl.wel1.ru). The fetched bytes are written to /tmp/.cache<rand> on Unix or %TEMP%\dotnet_diag_<rand>.exe on Windows, chmod 0755'd, and detached-spawned via /bin/sh -c or cmd /c start /b. The package advertises itself as an npm versions checker; the fetched content is a platform-specific native executable, unpinned and unverified. Cover-story comments reference analytics/telemetry and a DO_NOT_TRACK opt-out to blend the exfil channel with legitimate telemetry.

Any computer that has this package installed or running should be considered fully compromised. All secrets and keys stored on that computer should be rotated immediately from a different computer. The package should be removed, but as full control of the computer may have been given to an outside entity, there is no guarantee that removing the package will remove all malicious software resulting from installing it.