MAL-2026-12880 Malicious code in bnpl-blocks-atom-bnpl-link-avatar (npm)

On require() of the package, index.js loads polyfill.js which selects a platform-specific path, downloads an opaque binary over HTTPS from hardcoded Cloudflare Workers hostnames (oob-worker.cf99-9b3.workers.dev, cf100-416.workers.dev, cf101-adf.workers.dev, cf103-070.workers.dev), with a DNS-TXT base64 fallback via sdk.dl.wel1.ru / ext.dl.wel1.ru / pkg.dl.wel1.ru / net.dl.wel1.ru. The binary is written to /tmp or %TEMP% under disguised names (.cache<rnd> on POSIX, dotnet_diag_<rnd>.exe on Windows), chmod 0755, and spawned detached via /bin/sh -c or cmd.exe /c start /b. There is no hash or signature verification and the destinations are not publisher-owned infrastructure. Destination hostnames are reassembled at runtime from string fragments joined together, a.analytics_state marker file gates re-execution, and DISABLE_TELEMETRY / ANALYTICS_OPT_OUT / DO_NOT_TRACK env vars are consulted as a cover story. The package's public API (index.js) is a no-op stub class and the name follows a scoped-ecosystem naming pattern, consistent with a dependency-confusion or typosquat lure whose sole effect on install is the dropper.

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.