Intrusion Detection Message Exchange Format (IDMEF) XML output plugin for Snort – Produces IDMEF messages in response to events triggering Snort rules. It is configured in a standard Snort configuration file, and can run concurrently with existing Snort logging output.
You can download it from the following link: https://packetstormsecurity.com/files/download/23851/IDMEF-xml-plugin_0.1.tar.gz
Source: https://packetstormsecurity.com/files/23851/IDMEF-xml-plugin_0.1.tar.gz.html