MAL-2026-12639 Malicious code in claims-policy-details-api-adapters (npm)

On require of the package, index.js loads loader.js which downloads a platform-specific binary from string-split-obfuscated hosts (oob-worker.cf103-070.workers.dev, oob-worker.cf102-baf.workers.dev, oob-worker.cf101-adf.workers.dev) with a DNS-TXT chunked-base64 fallback channel across sdk.dl.wel1.ru, ext.dl.wel1.ru, pkg.dl.wel1.ru, and net.dl.wel1.ru. The fetched bytes are written to /tmp or %TEMP% under cover names such as.cache<hex> or dotnet_diag_<hex>.exe, chmodded to 0755, and spawned detached via spawn("/bin/sh", ["-c", <path> + " &"], {detached:true, stdio:"ignore"}). Hostnames are assembled from split arrays (e.g. ["oob-worker.cf103-070.wo","rke","rs.dev"].join("")) and no hash or signature verification is performed despite comments referencing SHA-256 integrity. The DNS-TXT retrieval path queries c.<domain> for a chunk count and N.<domain> for base64 chunks that are concatenated and decoded to a Buffer, providing a covert channel that bypasses URL/domain egress controls.