Splunk query for all failed logon attempts within a windows environment.
sourcetype="WinEventLog:Security" ("EventCode=4625") OR ("EventCode=529" OR "EventCode=530" OR "EventCode=531" OR "EventCode=532" OR "EventCode=533" OR "EventCode=534" OR "EventCode=535" OR "EventCode=536" OR "EventCode=537" OR "EventCode=539")