topic Re: Barracuda WAF (Web Application Firewall) truncating query string to access log and in turn into Splunk in Getting Data In

Barracuda WAF (Web Application Firewall) truncating query string to access log and in turn into Splunk

Maycockk — Fri, 29 Jan 2021 10:06:55 GMT

Good morning fellow Splunkers,

This might be a bit more of a Barracuda WAF question than a Splunk question but perhaps someone on here has overcome it already.

We're writing our Barracuda Access Logs into Splunk and noticed that the query string is coming through truncated. In the context of the WAF passing request through to appropriate location and functioning correctly that's absolutely fine. The writing to access log and in turn into Splunk is where we observe the truncation.

Any thoughts or ideas here?
We use a custom format string to submit to Splunk as follows:

%t %un %lt %ai %ap %ci %cp %id %cu %m %p %h %v %s %bs %br %rtf %pmf %pf %wmf %u %px %pp %tt %uid %q %r %c

Appreciate all tips/help here. Instructions are found in the waf_export_logs.pdf and query string is specified by %q above.

See attached pics below.

Re: Barracuda WAF (Web Application Firewall) truncating query string to access log and in turn into Splunk

Maycockk — Fri, 29 Jan 2021 10:08:18 GMT

Re: Barracuda WAF (Web Application Firewall) truncating query string to access log and in turn into Splunk

scelikok — Sat, 30 Jan 2021 05:21:44 GMT

Hi @Maycockk,

If event are truncated at 10K bytes, you may have increase TRUNCATE value in your props.conf at indexer or heavy forwarder. This value is 10K default.

[barracuda_waf_sourcetype] TRUNCATE = 20000

Re: Barracuda WAF (Web Application Firewall) truncating query string to access log and in turn into Splunk

Maycockk — Mon, 01 Feb 2021 10:01:38 GMT

Thanks scelikok,

My gut feeling is this is an issue on the Barracuda side. I believe what's being sent to the access log (which in turn is being forward to Splunk) is truncated at log level. I'm hoping someone has encountered/resolved this specific problem before.