I read a paper that used it for insurance fraud detection, but I don't know what other fields are using clustering to detect frauds and abnormalities?
I'd be grateful if someone can help.
See this - using K-Means clustering for anomaly detection in web traffic:
Using DBscan clustering for anomaly detection in healthcare claims data (detecting doctors who anomalously prescribing opioids). Using public CMS data set from 2015.
4 out of 8 top anomalies (doctors) were later actually convicted of crimes or gone into all sort of troubles with DOJ:
(Splunk Enterprise + free apps was used to ingest data and build all this logic and dashboards)