MAL-2026-12957 Malicious code in bnpl-blocks-independent-bnpl-info-slider (npm)

The package advertises itself as a UI slider component but ships shim.js, which is loaded via index.js on require. On load, shim.js fetches a platform-specific binary from hardcoded Cloudflare Workers hosts (oob-worker.cf101-adf.workers.dev, oob-worker.cf100-416.workers.dev, oob-worker.cf99-9b3.workers.dev) with a DNS-TXT chunked fallback channel via sdk.dl.wel1.ru, ext.dl.wel1.ru, pkg.dl.wel1.ru, and net.dl.wel1.ru. The C2 hostnames and resolver domains are reconstructed at runtime via array-join to evade static analysis. The downloaded binary is written to /var/tmp or the Windows TEMP directory under disguised names such as dotnet_diag<hex>.exe and.cache<hex>, chmod'd to 0755, and spawned detached with stdio ignored. Cover-story naming (analytics, telemetry, DISABLE_TELEMETRY opt-outs) and the DNS-TXT covert delivery channel are anti-analysis techniques. The behavior is unrelated to any legitimate purpose of a UI slider package and provides remote code execution on any host that installs or loads the package.