The easiest solutions would be to integrate Umbrella with SecureX and use SecureX APIs and Orchestration to automate this scenario.
Create SecureX Orchestration workflow to do the following:
1. Pull CSV file from web resource (S3 bucket for example).
2. Inspect CSV file content with SecureX Inspect API to convert free form text into formatted list of observables
3. Use this list as input into SecureX Deliberate API call to find out status of all observables (Malicious, Clean, etc)
4. For Malicious/Unknown observables - use SecureX Enrich API to find any sightings (have these observables been seen in your environment).
There are examples of similar workflows here.