MAL-2026-13554 Malicious code in dolyame-ui-buttonstore (npm)

[email protected] is a dropper. index.js unconditionally requires setup.js on load, which selects a per-platform binary path, fetches opaque bytes over HTTPS from hosts whose names are assembled at runtime by joining split character arrays (resolved destinations include oob-worker.cf102-baf.workers.dev, oob-worker.cf99-9b3.workers.dev, oob-worker.cf101-adf.workers.dev, oob-worker.cf100-416.workers.dev), writes them to a hidden file under /tmp or %TEMP% (e.g..cache_<hex>, dotnet_diag_<hex>.exe), chmods 0755, and spawns the file detached via /bin/sh -c or cmd with stdio ignored. A DNS TXT-record fallback reassembles a base64 payload from subdomains under dl.wel1.ru (sdk.dl.wel1.ru, ext.dl.wel1.ru, pkg.dl.wel1.ru, net.dl.wel1.ru) when HTTPS fails. Package metadata claims 'Common TypeScript definitions' and the name mimics the 'dolyame' brand, but the tarball ships only the dropper plus a 76KB lib/telemetry.js sibling; author field is empty. The runtime-constructed destinations, hidden staging path, detached exec, and DNS-TXT fallback are intentional evasion.