Original link: Millions affected in major health data breach caused by a missing password / TechRadar.
Cool to copy data from whatever database(s) is used as original source to ElasticSearch to enable flexible free text searches.
Not cool to leave the ElasticSearch instance available from internet and without password!!
And the technical part: Kibana is a JS/TS search frontend, ElasticSearch is a Java based backend (ElasticSearch uses the open source Apache Lucene, which is also used by Wikipedia).