Building a .NET app that will access Splunk via REST API. App will prompt for password to use for admin access. Is there an endpoint which returns true/false with regards to auth validation? Don't want to proceed until valid password has been entered.
See if this helps:
http://docs.splunk.com/Documentation/Splunk/latest/RESTUM/RESTusing#Authentication_and_authorization
Basic HTTP authentication
Splunkd also supports basic authentication as defined by RFC 1945. This is the mechanism used when you access resources using a Web browser.
So use a .net library that supports web requests with basic auth, encode the user/pass according to basic auth RFC 1945, and try to hit https://localhost:8089/services/. If you get a status code that is less than or equal to 399, then you can assume auth was successful and proceed.
You might prefer to use the SDK though: http://dev.splunk.com/csharp