{
  "port": 10243,
  "protocol": "tcp",
  "service": "Windows Media Player Network Sharing (HTTP)",
  "oneLiner": "A Windows machine with media streaming enabled — HTTP.sys serving the WMPNSSv4 endpoint.",
  "whatItIs": "Not registered with IANA, but on Windows it is entirely predictable: the Windows Media Player Network Sharing Service reserves the URL http://+:10243/WMPNSSv4/ with HTTP.sys under the NT SERVICE\\WMPNetworkSvc account, so the port opens whenever media streaming or DLNA sharing is turned on — often by a setup wizard rather than a deliberate choice. It is the HTTP half of the UPnP AV media server, advertised over SSDP on UDP 1900. Nmap sees it open on about 0.07% of scanned hosts, essentially all Windows.",
  "exposure": {
    "verdict": "never",
    "note": "A LAN media-sharing surface with no business on a public IP: it exposes the library to anyone who can reach it and puts HTTP.sys, historically a source of remote vulnerabilities, on the wire. Turn media streaming off if you are not using it."
  },
  "checkCommand": "curl -sSI http://TARGET:10243/WMPNSSv4/",
  "links": [
    {
      "title": "IANA port registry — 10243 (no assignment)",
      "url": "https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml?search=10243",
      "kind": "iana"
    },
    {
      "title": "nmap-services — Nmap's port frequency database",
      "url": "https://github.com/nmap/nmap/blob/master/nmap-services",
      "kind": "github"
    }
  ]
}