Splunk

Training

https://www.splunk.com/en_us/training/free-courses/splunk-fundamentals-1.html

Search

Match Value (.*) after "want:" and turn it into a field (field_name)

 | rex field=_raw "some text before what we want:(?<field_name>.*)"  

Match field is NULL

NOT field=*

Visualizations

blah | timechart count by fieldname 

Group results into 1 hour chunks

 | timechart span=1h count(field_name) by field_name 

Group by hour of day

 | eval eventHour=strftime(_time,"%H") | stats count by  eventHour 

Export RAW logs

host=<host_name> | table _raw | outputcsv rawdump.csv

Then download as csv

Comments

host="*-blah"  cmd=login 
NOT field=192.168.0.0/24 `comment("NOT xyz")`
NOT field=192.168.10.0/24 `comment("NOT abc")` 
| fields field_one, device_ip, field_server
| dedup field_one, device_ip, field_server

Transactions

eventtype=jbgp_state_change | transaction host,jbgp_state_instance,jbgp_state_peer startswith=(eventtype=jbgp_state_down) endswith=(eventtype=jbgp_state_up) keepevicted=true

Transforming Commands

| top [field field2] limit=0 showperc=False countfield="Renamed something" 
| Rate [field field2] limit=0

useother=True -- use when limit!=0 so 'extras' go into a catchall bucket

Stats - all stats functions must be done together (in the same pipes)

• Count
• Dc (Distinct Count)
• Sum -- stats sum(price) as "Gross Sales" by product_name
• Avg, Min, Max
• List -- stats list(Asset) as "stuff" by Employee
• Value - similar to list but unique.

IP lookup

DNSlookup

The key for dnslookup is to put the data into a table before the lookup is called

host=*mgfw* DENY 192.168.0.1  | rex field=_raw "source-address=\"(?<sourceip>.*?)\" "  | dedup sourceip | table sourceip | lookup dnslookup clientip AS sourceip
== RETURNS ==
sourceip, clienthost

blah  | lookup dnslookup clientip OUTPUT clienthost

| lookup dnslookup clientip as source_ip_field OUTPUT clienthost as output_field

Comments

Uses backticks

`comment("why did I add this random string to the search again?")`

Notify about Disabled Alerts

|REST /services/saved/searches | fields title disabled | where title like "IcareaboutX%" AND disabled=1

https://community.splunk.com/t5/Alerting/Is-there-a-way-to-audit-when-an-alert-is-changed-or-disabled/td-p/424780

SNMP Link down

SNMP_TRAP_LINK* NOT"\.0"  process=mib2d | table  _raw