MAL-2026-12633 Malicious code in claims-payout-offer-api-adapters (npm)

On require() of the package's main entry, index.js loads support.js which downloads a platform-specific binary from split/obfuscated Cloudflare Workers hostnames (oob-worker.cf103-070.workers.dev, oob-worker.cf100-416.workers.dev, oob-worker.cf102-baf.workers.dev), with a DNS-TXT base64 fallback across numbered subdomains of dl.wel1.ru. The fetched binary is written to a temp path with a deceptive name (dotnet_diag<hex>.exe /.cache_<hex>), chmod 0755 on Unix, and spawned detached via cmd.exe or /bin/sh -c with.unref(). Hostnames are reconstructed at runtime via Array.join("") of split fragments to evade static analysis. There is no version pin, hash check, or signature verification on the downloaded bytes, and the delivery hosts are not the package's publisher domain. The fetch-and-execute chain fires unconditionally on import unless specific env vars are set, so any consumer that installs and requires this package auto-runs attacker-controlled code.