This can be used as a vector for amplified DDoS attacks. It is recommended you configure your server in such a way that only authenticated streams are provided using the UDP protocol, while rejecting SOURCETABLE requests.
You can test your server by sending a UDP packet to it with the following payload: '0x80, 0x61, 0x04, 0xd2, 0x00, 0xbc, 0x61, 0x4e, 0x00, 0x00, 0x00, 0x00, 0x47, 0x45, 0x54, 0x20, 0x2f, 0x20, 0x48, 0x54, 0x54, 0x50, 0x2f, 0x31, 0x2e, 0x31, 0x0d, 0x0a, 0x0d, 0x0a'. If you get a large response your configuration is vulnerable.
Please note that this example request is not entirely valid, as information such as the server hostname is not filled in. However, we have not seen any server that cares about this. If this is a problem for you, please refer to the NTRIPv2 standard on how to encode the payload.