ID | Technique | Tactic |
---|---|---|
T1003.006 | DCSync | Credential Access |
T1003 | OS Credential Dumping | Credential Access |
Detection: Windows AD Replication Request Initiated from Unsanctioned Location
Description
The following analytic identifies unauthorized Active Directory replication requests initiated from non-domain controller locations. It leverages EventCode 4662 to detect when a computer account with replication permissions creates a handle to domainDNS, filtering out known domain controller IP addresses. This activity is significant as it may indicate a DCSync attack, where an attacker with privileged access can request password hashes for any or all users within the domain. If confirmed malicious, this could lead to unauthorized access to sensitive information and potential full domain compromise.
Search
1`wineventlog_security` EventCode=4662 ObjectType IN ("%{19195a5b-6da0-11d0-afd3-00c04fd930c9}", "domainDNS") AND Properties IN ("*Replicating Directory Changes All*", "*{1131f6ad-9c07-11d1-f79f-00c04fc2dcd2}*", "*{9923a32a-3607-11d2-b9be-0000f87a36b2}*","*{1131f6ac-9c07-11d1-f79f-00c04fc2dcd2}*") AND AccessMask="0x100" AND (SubjectUserSid="NT AUT*" OR SubjectUserSid="S-1-5-18" OR SubjectDomainName="Window Manager" OR SubjectUserName="*$")
2| stats min(_time) as attack_time, count by SubjectDomainName, SubjectUserName, Computer, Logon_ID, ObjectName, ObjectServer, ObjectType, OperationType, status
3| rename SubjectDomainName as Target_Domain, SubjectUserName as user, Logon_ID as TargetLogonId
4| appendpipe [
5| map search="search `wineventlog_security` EventCode=4624 TargetLogonId=$TargetLogonId$"]
6| table attack_time, AuthenticationPackageName, LogonProcessName, LogonType, TargetUserSid, Target_Domain, user, Computer, TargetLogonId, status, src_ip, src_category, ObjectName, ObjectServer, ObjectType, OperationType
7| stats min(attack_time) as _time, values(TargetUserSid) as TargetUserSid, values(Target_Domain) as Target_Domain, values(user) as user, values(Computer) as Computer, values(status) as status, values(src_category) as src_category, values(src_ip) as src_ip by TargetLogonId
8| search NOT src_category="domain_controller"
9| `windows_ad_replication_request_initiated_from_unsanctioned_location_filter`
Data Source
Name | Platform | Sourcetype | Source |
---|---|---|---|
Windows Event Log Security 4624 | Windows | 'xmlwineventlog' |
'XmlWinEventLog:Security' |
Windows Event Log Security 4662 | Windows | 'xmlwineventlog' |
'XmlWinEventLog:Security' |
Macros Used
Name | Value |
---|---|
wineventlog_security | eventtype=wineventlog_security OR Channel=security OR source=XmlWinEventLog:Security |
windows_ad_replication_request_initiated_from_unsanctioned_location_filter | search * |
windows_ad_replication_request_initiated_from_unsanctioned_location_filter
is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
Annotations
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 Notable | Yes |
Rule Title | %name% |
Rule Description | %description% |
Notable Event Fields | user, dest |
Creates Risk Event | True |
Implementation
To successfully implement this search, you need to be ingesting eventcode 4662
. The Advanced Security Audit policy settings Audit Directory Services Access
within DS Access
needs to be enabled, as well as the following SACLs applied to the domain root and all descendant objects. The principals everybody
, Domain Computers
, and Domain Controllers
auditing the permissions Replicating Directory Changes
, Replicating Directory Changes All
, and Replicating Directory Changes In Filtered Set
Assets and Identities will also need to be configured, with the category of domain_controller added for domain controllers.
Known False Positives
Genuine DC promotion may trigger this alert.
Associated Analytic Story
Risk Based Analytics (RBA)
Risk Message | Risk Score | Impact | Confidence |
---|---|---|---|
Windows Active Directory Replication Request Initiated from Unsanctioned Location $src_ip$ by $user$ | 100 | 100 | 100 |
References
Detection Testing
Test Type | Status | Dataset | Source | Sourcetype |
---|---|---|---|---|
Validation | ✅ Passing | N/A | N/A | N/A |
Unit | ✅ Passing | Dataset | XmlWinEventLog:Security |
XmlWinEventLog |
Integration | ✅ Passing | Dataset | XmlWinEventLog:Security |
XmlWinEventLog |
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: 5