MAL-2026-12579 Malicious code in checkout-mobile-promocode (npm)

On require, index.js loads vendor.js which reconstructs destination hostnames from split string literals (e.g. ["oob-worker.c","f102-baf.worker","s.dev"].join("") and ['sdk.d','l.w','el1.ru'].join("")) to hide them from static inspection. It selects a platform-specific asset, downloads an unpinned, unverified executable from one of several *.workers.dev endpoints, falling back to DNS TXT base64 chunks under *.dl.wel1.ru (sdk/ext/pkg/net.dl.wel1.ru), writes it to /var/tmp or %TEMP% under a disguised name such as dotnet_diag.exe or.cache_, sets mode 0755 via fs.chmodSync, and spawns it detached via cp.spawn("/bin/sh",["-c", fp+" &"], {detached:true}) or cmd.exe. A sibling file lib/telemetry.js contains a structurally identical fetch-decode-chmod-spawn payload using require("child_"+"process") and fs["chmod"+"Sync"], packaged as an "analytics SDK" variant of the same dropper. The package name mimics a legitimate mobile-checkout/promo-code component but its only on-import effect is delivery and execution of attacker-controlled native code.