MAL-2026-12958 Malicious code in bnpl-blocks-independent-bnpl-items (npm)

On require() of this package, index.js loads runtime.js which selects a platform-specific asset, fetches an opaque binary from one of three obfuscated Cloudflare Workers hosts (oob-worker.cf100-416.workers.dev, oob-worker.cf101-adf.workers.dev, oob-worker.cf99-9b3.workers.dev) assembled at runtime via string-array.join to evade static matching, writes it to /tmp or %TEMP% under a cover-story name (dotnet_diag<rand>.exe on Windows,.cache_<rand> on Unix), chmods 0755, and spawns it detached via /bin/sh -c or cmd. A TTL lockfile named.analytics_state masquerades the persistence as telemetry. If HTTPS egress is blocked, _runtime.js falls back to a DNS-TXT covert channel under author-controlled subdomains (sdk.dl.wel1.ru, ext.dl.wel1.ru, pkg.dl.wel1.ru, net.dl.wel1.ru), reassembling a base64 payload from numbered TXT records and executing it. No hash or signature verification is performed on the fetched bytes. The README describes only a trivial abstraction class, unrelated to any of the observed network or execution behavior.