So, I recently read an article discussing the difficulty of and various approaches to catching new or unknown botnet activity. This made me wonder if it would be possible to monitor for possible botnet activity with a Splunk search.
I've been trying to formulate a search in Splunk that would basically look for synchronized beaconing but I'm drawing a blank on how to structure the search.
I would basically want the search to look for multiple hosts contacting the same IP at the same time +/- a few seconds to account for slight time diff in logs.
As an approach, you could go for timechart dc(host) by dest_ip, filtering out all known destinations. Those unknown dest_ips having a high number of hosts in a small time slice may be what you're looking for.