CSA

Cisco Security Agent

CSA can be configured to export to flat file:

http://www.cisco.com/en/US/docs/security/csa/csa50/user_guide/Chap10.html#wp963302

Finally, just install and configure a Splunk forwarder on the CSA MC server.

http://www.splunk.com/doc/latest/admin/ForwardingandReceiving