:warning: THIS IS A EXPERIMENTAL DETECTION

This detection has been marked experimental by the Splunk Threat Research team. This means we have not been able to test, simulate, or build datasets for this detection. Use at your own risk. This analytic is NOT supported.

Try in Splunk Security Cloud

Description

This search looks for evidence of Active Directory replication traffic [MS-DRSR] from unexpected sources. This traffic is often seen exclusively between Domain Controllers for AD database replication. Any detections from non-domain controller source to a domain controller may indicate the usage of DCSync or DCShadow credential dumping techniques.

  • Type: TTP
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel: Network_Traffic, Network_Sessions
  • Last Updated: 2022-11-26
  • Author: Steven Dick
  • ID: c6e24183-a5f4-4b2a-ad01-2eb456d09b67

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1003 OS Credential Dumping Credential Access
T1003.006 DCSync Credential Access
T1207 Rogue Domain Controller Defense Evasion
Kill Chain Phase
  • Exploitation
  • Actions on Objectives
NIST
  • DE.CM
CIS20
  • CIS 3
  • CIS 5
  • CIS 16
CVE 


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| tstats `security_content_summariesonly` count values(All_Traffic.transport) as transport values(All_Traffic.user) as user values(All_Traffic.src_category) as src_category values(All_Traffic.dest_category) as dest_category min(_time) as firstTime max(_time) as lastTime from datamodel=Network_Traffic where All_Traffic.app IN ("ms-dc-replication","*drsr*","ad drs") by All_Traffic.src All_Traffic.dest All_Traffic.app 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `drop_dm_object_name("All_Traffic")` 
| `active_directory_replication_traffic_from_unknown_source_filter` 
| `windows_ad_replication_service_traffic_filter`

Macros

The SPL above uses the following Macros:

:information_source: windows_ad_replication_service_traffic_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Required fields

List of fields required to use this analytic.

  • All_Traffic.src
  • All_Traffic.dest
  • All_Traffic.app

How To Implement

To successfully implement this search, you need to be ingesting application aware firewall or proxy logs into the Network Datamodel. Categorize all known domain controller Assets servers with an appropriate category for filtering.

Known False Positives

New domain controllers or certian scripts run by administrators.

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
100.0 100 100 Active Directory Replication Traffic from Unknown Source - $src$

:information_source: The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

Reference

Test Dataset

Replay any dataset to Splunk Enterprise by using our replay.py tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range

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