Windows DnsAdmins New Member Added

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Description

The following analytic leverages Event ID 4732 to identify the addition of a new member to the DnsAdmins group within Active Directory. . Members of the DnsAdmin group can manage the DNS service which most of the times runs on the Domain Controller. By abusing legitimate DNS management functionality, a member of the DnsAdmins group can escalate privileges by executing malicious code on a Domain Controller as SYSTEM. Security teams should monitor the modification of the DnsAdmins group and validate the changes are legitimate.

• Type: TTP

• Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud

• Last Updated: 2023-04-06
• Author: Mauricio Velazco, Splunk
• ID: 27e600aa-77f8-4614-bc80-2662a67e2f48

Annotations

ATT&CK

ATT&CK

ID	Technique	Tactic
T1098	Account Manipulation	Persistence

Kill Chain Phase

• Installation

NIST

• DE.CM

CIS20

• CIS 10

CVE

Search

 `wineventlog_security` EventCode=4732 TargetUserName=DnsAdmins 
| stats min(_time) as firstTime max(_time) as lastTime values(SubjectUserName) values(Computer) by MemberSid, TargetUserName 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `windows_dnsadmins_new_member_added_filter`

Macros

The SPL above uses the following Macros:

• wineventlog_security
• security_content_ctime

windows_dnsadmins_new_member_added_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.

• _time
• EventCode
• TargetUserName
• SubjectUserName
• Computer
• MemberSid
• TargetUserName

How To Implement

To successfully implement this search, Domain Controller events need to be ingested. The Advanced Security Audit policy setting Audit Security Group Management within Account Management needs to be enabled.

Known False Positives

New members can be added to the DnsAdmins group as part of legitimate administrative tasks. Filter as needed.

Associated Analytic Story

• Active Directory Privilege Escalation

RBA

Risk Score	Impact	Confidence	Message
40.0	80	50	A new member was added to the DnsAdmins group by $SubjectUserName$

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

• https://attack.mitre.org/techniques/T1098/
• https://www.ired.team/offensive-security-experiments/active-directory-kerberos-abuse/from-dnsadmins-to-system-to-domain-compromise
• https://www.hackingarticles.in/windows-privilege-escalation-dnsadmins-to-domainadmin/
• https://learn.microsoft.com/en-us/windows/security/threat-protection/auditing/event-4732

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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