Detection: Windows AD Replication Service Traffic

EXPERIMENTAL DETECTION

This detection status is set to experimental. The Splunk Threat Research team has not yet fully tested, simulated, or built comprehensive datasets for this detection. As such, this analytic is not officially supported. If you have any questions or concerns, please reach out to us at research@splunk.com.

Updated Date: 2026-05-13 ID: c6e24183-a5f4-4b2a-ad01-2eb456d09b67 Author: Steven Dick Type: TTP Product: Splunk Enterprise Security

Description

The following analytic identifies unexpected Active Directory replication traffic from non-domain controller sources. It leverages data from the Network Traffic datamodel, specifically looking for applications related to AD replication. This activity is significant because AD replication traffic should typically only occur between domain controllers. Detection of such traffic from other sources may indicate malicious activities like DCSync or DCShadow, which are used for credential dumping. If confirmed malicious, this could allow attackers to exfiltrate sensitive credentials, leading to unauthorized access and potential domain-wide compromise.

Search

 1
 2| 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
 3  WHERE All_Traffic.app IN ("ms-dc-replication","*drsr*","ad drs")
 4  BY All_Traffic.src All_Traffic.dest All_Traffic.app
 5
 6| `security_content_ctime(firstTime)`
 7
 8| `security_content_ctime(lastTime)`
 9
10| `drop_dm_object_name("All_Traffic")`
11
12| `windows_ad_replication_service_traffic_filter`

Data Source

No data sources specified for this detection.

Macros Used

Name	Value
security_content_ctime	`convert timeformat="%Y-%m-%dT%H:%M:%S" ctime($field$)`
windows_ad_replication_service_traffic_filter	`search *`

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

Annotations

- MITRE ATT&CK

+ Kill Chain Phases

+ NIST

+ CIS

- Threat Actors

ID	Technique	Tactic
T1003.006	DCSync	Credential Access
T1207	Rogue Domain Controller	Defense Impairment

Exploitation

DE.CM

CIS 13

Default Configuration

This detection is configured by default in Splunk Enterprise Security to run with the following settings:

Setting	Value
Disabled	true
Cron Schedule	`0 * * * *`
Earliest Time	`-70m@m`
Latest Time	`-10m@m`
Schedule Window	`auto`
Creates Finding (Notable)	Yes
Rule Title	`%name%`
Rule Description	`%description%`
Notable Event Fields	user, dest
Creates Intermediate Finding (Risk Event)	No

TTP detections generate a Finding (Notable) and may generate Intermediate Findings (Risk Events) for associated entities.

Implementation

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

Sneaky Active Directory Persistence Tricks

Finding

Title	Entity Field	Entity Type	Risk Score
Active Directory Replication Traffic from Unknown Source - $src$	dest	system	50

Threat Objects

Field	Type
src	ip_address

References

Detection Testing

Test Type	Status	Dataset	Source	Sourcetype
Validation	Not Applicable	N/A	N/A	N/A
Unit	❌ Failing	N/A	`N/A`	`N/A`
Integration	❌ Failing	N/A	`N/A`	`N/A`

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

Source: GitHub | Version: 9