name: Baseline of SMB Traffic - MLTK
id: df98763b-0b08-4281-8ef9-08db7ac572a9
version: 1
date: '2019-05-08'
author: Rico Valdez, Splunk
type: batch
datamodel:
- Network_Traffic
description: This search is used to build a Machine Learning Toolkit (MLTK) model
  to characterize the number of SMB connections observed each hour for every day of
  week. By default, the search uses the last 30 days of data to build the model. The
  model created by this search is then used in the corresponding detection search
  to identify outliers in the number of SMB connections for that hour and day of the
  week.
search: '| tstats `security_content_summariesonly` count from datamodel=Network_Traffic
  where All_Traffic.dest_port=139 OR All_Traffic.dest_port=445 OR All_Traffic.app=smb
  by _time span=10m, All_Traffic.src | eval HourOfDay=strftime(_time, "%H") | eval
  DayOfWeek=strftime(_time, "%A") | `drop_dm_object_name("All_Traffic")` | fit DensityFunction
  count by "HourOfDay,DayOfWeek" into smb_pdfmodel'
how_to_implement: You must be ingesting network traffic and populating the Network_Traffic
  data model. In addition, you must have the Machine Learning Toolkit (MLTK) version
  >= 4.2 installed, along with any required dependencies. To improve your results,
  you may consider adding "src" to the by clause, which will build the model for each
  unique source in your enviornment. However, if you have a large number of hosts
  in your environment, this search may be very resource intensive. In this case, you
  may need to raise the value of max_inputs and/or max_groups in the MLTK settings
  for the DensityFunction algorithm, then ensure that the search completes in a reasonable
  timeframe. By default, the search builds the model using the past 30 days of data.
  You can modify the search window to build the model over a longer period of time,
  which may give you better results. You may also want to periodically re-run this
  search to rebuild the model with the latest data. More information on the algorithm
  used in the search can be found at `https://docs.splunk.com/Documentation/MLApp/4.2.0/User/Algorithms#DensityFunction`.
references: []
tags:
  analytic_story:
  - DHS Report TA18-074A
  - Disabling Security Tools
  - 'Emotet Malware  DHS Report TA18-201A '
  - Hidden Cobra Malware
  - Netsh Abuse
  - Ransomware
  detections:
  - Processes launching netsh
  - SMB Traffic Spike - MLTK
  product:
  - Splunk Enterprise
  - Splunk Enterprise Security
  - Splunk Cloud
