THIS IS A DEPRECATED DETECTION
This detection has been marked deprecated by the Splunk Threat Research team. This means that it will no longer be maintained or supported.
This search looks for web connections to dynamic DNS providers.
- Type: TTP
- Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Datamodel: Web
- Last Updated: 2020-07-21
- Author: Bhavin Patel, Splunk
- ID: 134da869-e264-4a8f-8d7e-fcd01c18f301
Kill Chain Phase
- Command and Control
- CIS 13
1 2 3 4 5 6 | tstats `security_content_summariesonly` count values(Web.url) as url min(_time) as firstTime from datamodel=Web where Web.status=200 by Web.src Web.dest Web.status | `drop_dm_object_name("Web")` | `security_content_ctime(firstTime)` | `dynamic_dns_web_traffic` | `detect_web_traffic_to_dynamic_domain_providers_filter`
The SPL above uses the following Macros:
detect_web_traffic_to_dynamic_domain_providers_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
List of fields required to use this analytic.
How To Implement
This search requires you to be ingesting web-traffic logs. You can obtain these logs from indexing data from a web proxy or by using a network-traffic-analysis tool, such as Bro or Splunk Stream. The web data model must contain the URL being requested, the IP address of the host initiating the request, and the destination IP. This search also leverages a lookup file,
dynamic_dns_providers_default.csv, which contains a non-exhaustive list of dynamic DNS providers. Consider periodically updating this local lookup file with new domains.
This search produces fields (
isDynDNS) 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: IsDynamicDNS, Field: isDynDNS
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 Deprecated because duplicate.
Known False Positives
It is possible that list of dynamic DNS providers is outdated and/or that the URL being requested is legitimate.
Associated Analytic Story
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.
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