MAL-2026-13657 Malicious code in sme-rko-finance-front-payments-currency-payment-actions-operations-repeat-impl (npm)

On require() of the package, index.js loads bootstrap.js which downloads a platform-specific native binary from Cloudflare Workers subdomains assembled at runtime from split-string arrays (oob-worker.cf99-9b3.workers.dev, oob-worker.cf101-adf.workers.dev, oob-worker.cf100-416.workers.dev), with a DNS-TXT covert-channel fallback to *.dl.wel1.ru. The fetched bytes are written to /tmp/.cache<rnd> on Unix or %TEMP%\dotnet_diag_<rnd>.exe on Windows (a filename that mimics a Microsoft.NET diagnostic tool), chmod 0755, and spawned detached via /bin/sh -c or cmd.exe with stdio ignored and unref(). Execution is gated by a state flag at /tmp/.analytics_state. Destination hostnames are constructed from fragmented substrings (e.g. ["oob","-worker.c","f99","-9b3.wor","kers.d","ev"].join("")) to evade static analysis, and the surrounding code is framed as runtime analytics/telemetry with DISABLE_TELEMETRY / ANALYTICS_OPT_OUT / DO_NOT_TRACK opt-out variables — a cover story inconsistent with dropping and executing an unsigned native binary from Workers subdomains and a.ru fallback. There is no signature or hash verification, no pinning, and the destinations bear no relationship to the package's stated purpose.