DNS Query Length Outliers - MLTK

Description

This search allows you to identify DNS requests that are unusually large for the record type being requested in your environment.

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DNS Query Length Outliers - MLTK Help

To successfully implement this search, you will need to ensure that DNS data is populating the NetworkResolution data model. In addition, the Machine Learning Toolkit (MLTK) version 4.2 or greater must be installed on your search heads, along with any required dependencies. Finally, the support search "Baseline of DNS Query Length - MLTK" must be executed before this detection search, because it builds a machine-learning (ML) model over the historical data used by this search. It is important that this search is run in the same app context as the associated support search, so that the model created by the support search is available for use. You should periodically re-run the support search to rebuild the model with the latest data available in your environment.\ This search produces fields (query,query_length,count) that are not yet supported by ES Incident Review and therefore cannot be viewed when a notable event is raised. These fields contribute additional context to the notable. To see the additional metadata, add the following fields, if not already present, to Incident Review - Event Attributes (Configure > Incident Management > Incident Review Settings > Add New Entry):\n1. Label: DNS Query, Field: query\ 1. \ 1. Label: DNS Query Length, Field: querylength\ 1. \ 1. Label: Number of events, Field: count\ Detailed documentation on how to create a new field within Incident Review may be found here: https://docs.splunk.com/Documentation/ES/5.3.0/Admin/Customizenotables#Add_a_field_to_the_notable_event_details

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   Baseline Generation Searches

This detection relies on the following search to generate the baseline lookup.

  • Baseline of DNS Query Length - MLTK