topic Re: Excluding some event log data from being forwarded to the indexers in Getting Data In

Excluding some event log data from being forwarded to the indexers

bobmorning — Fri, 18 Mar 2022 04:45:46 GMT

We have an outside scanning agency that is constantly doing nmap like scans of our perimeter. It is generating a log of log data on the perimeter CISCO firewalls. We know the IPs that the scanning is coming from; is there a way to tell the forwarders to NOT forward that log data from the firewalls for those IPs?

For example, if any tcp/ip log data is seen from 1.2.3.4, don't forward it, but if from any other IP address, treat it normally and forward it.

Thanks for any insights on this. Our Splunk SME are looking at CRIBL to do this but reading this thread makes me believe there are configuration settings that might address this?

V/R Bob M.

Re: Excluding some event log data from being forwarded to the indexers

richgalloway — Sat, 19 Mar 2022 12:44:55 GMT

Universal Forwarders cannot filter that input. Cribl is a good choice or you can use a transform at the indexer/heavy forwarder to send undesired events to the null queue.

Re: Excluding some event log data from being forwarded to the indexers

PickleRick — Sat, 19 Mar 2022 16:07:29 GMT

How are you receiving logs from those firewall? Syslog?

If so, employ some syslog processing layer (it's worth doing anyway) - for example, sc4s or rsyslog-based collector. There you can filter at will.