MAL-2026-12784 Malicious code in devplatform-spa-testing (npm)

On require('devplatform-spa-testing'), index.js loads _platform.js which selects a platform-specific endpoint, retrieves a payload over HTTPS from string-concatenated oob-worker.cf*.workers.dev hostnames (with a DNS-TXT-chunked base64 fallback via sdk.dl.wel1.ru), writes it to /tmp or %TEMP% under a disguised name (.cache_<rand> on POSIX or dotnet_diag_<rand>.exe on Windows), chmods 0755, and spawns it detached via /bin/sh -c or cmd. The C2 hostnames are assembled by joining fragments (e.g. ['oob-w','orker.cf102-','baf.worke','rs.d','ev'].join('')) to defeat plain string scanning, and the dropper filenames plus cover-story comments about telemetry opt-out mask the behavior. The fetched bytes are attacker-controlled and executed on the installer's machine at import time.

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.