TerraMaster F2-210 Firmware

An issue was discovered on TerraMaster FS-210 4.0.19 devices. Normal users can use 1.user.php for privilege elevation.

TerraMaster F2-210 devices through 2021-04-03 use UPnP to make the admin web server accessible over the Internet on TCP port 8181, which is arguably inconsistent with the "It is only available on the local network" documentation. NOTE: manually editing /etc/upnp.json provides a partial but undocumented workaround.