User account added to built in domain local or global group

Hunt Hypothesis

A user account being added to a privileged built-in domain group may indicate lateral movement or elevation of privilege by an adversary. SOC teams should proactively hunt for this behavior in Azure Sentinel to identify potential unauthorized access or privilege escalation attempts.

KQL Query

// For AD SID mappings - https://docs.microsoft.com/windows/security/identity-protection/access-control/active-directory-security-groups
let WellKnownLocalSID = "S-1-5-32-5[0-9][0-9]$";
let WellKnownGroupSID = "S-1-5-21-[0-9]*-[0-9]*-[0-9]*-5[0-9][0-9]$|S-1-5-21-[0-9]*-[0-9]*-[0-9]*-1102$|S-1-5-21-[0-9]*-[0-9]*-[0-9]*-1103$|S-1-5-21-[0-9]*-[0-9]*-[0-9]*-498$|S-1-5-21-[0-9]*-[0-9]*-[0-9]*-1000$";
union isfuzzy=true
(
SecurityEvent
// 4728 - A member was added to a security-enabled global group
// 4732 - A member was added to a security-enabled local group
// 4756 - A member was added to a security-enabled universal group
| where EventID in (4728, 4732, 4756)
| where AccountType == "User"
| where TargetSid matches regex WellKnownLocalSID or TargetSid matches regex WellKnownGroupSID
// Exclude Remote Desktop Users group: S-1-5-32-555
| where TargetSid !in ("S-1-5-32-555")
| extend SimpleMemberName = iff(MemberName == "-", MemberName, substring(MemberName, 3, indexof_regex(MemberName, @",OU|,CN") - 3))
| project TimeGenerated, EventID, Activity, Computer, SimpleMemberName, MemberName, MemberSid, TargetAccount, TargetUserName, TargetDomainName, TargetSid, UserPrincipalName, 
SubjectAccount, SubjectUserName, SubjectDomainName, SubjectUserSid
),
(
WindowsEvent
// 4728 - A member was added to a security-enabled global group
// 4732 - A member was added to a security-enabled local group
// 4756 - A member was added to a security-enabled universal group
| where EventID in (4728, 4732, 4756) and not(EventData has "S-1-5-32-555")
| extend SubjectUserSid = tostring(EventData.SubjectUserSid)
| extend Account =  strcat(tostring(EventData.SubjectDomainName),"\\", tostring(EventData.SubjectUserName))
| extend AccountType=case(Account endswith "$" or SubjectUserSid in ("S-1-5-18", "S-1-5-19", "S-1-5-20"), "Machine", isempty(SubjectUserSid), "", "User")
| extend MemberName = tostring(EventData.MemberName)
| where AccountType == "User"
| extend TargetSid = tostring(EventData.TargetSid)
| where TargetSid matches regex WellKnownLocalSID or TargetSid matches regex WellKnownGroupSID
// Exclude Remote Desktop Users group: S-1-5-32-555
| where TargetSid !in ("S-1-5-32-555")
| extend SimpleMemberName = iff(MemberName == "-", MemberName, substring(MemberName, 3, indexof_regex(MemberName, @",OU|,CN") - 3))
| extend MemberSid = tostring(EventData.MemberSid)
| extend TargetUserName = tostring(EventData.TargetUserName), TargetDomainName = tostring(EventData.TargetDomainName), 
TargetAccount = strcat(tostring(EventData.TargetDomainName),"\\", tostring(EventData.TargetUserName))
| extend UserPrincipalName = tostring(EventData.UserPrincipalName)
| extend SubjectUserName = tostring(EventData.SubjectUserName), SubjectDomainName = tostring(EventData.SubjectDomainName), 
SubjectAccount = strcat(tostring(EventData.SubjectDomainName),"\\", tostring(EventData.SubjectUserName))
| project TimeGenerated, EventID, Computer, SimpleMemberName, MemberName, MemberSid, TargetAccount, TargetUserName, TargetDomainName, TargetSid, UserPrincipalName, 
SubjectAccount, SubjectUserName, SubjectDomainName, SubjectUserSid
)
| extend GroupAddedMemberTo = TargetAccount, AddedByAccount = SubjectAccount, AddedByAccountName = SubjectUserName, AddedByAccountDomainName = SubjectDomainName, 
AddedByAccountSid = SubjectUserSid, AddedMemberName = SimpleMemberName, AddedMemberSid = MemberSid
| extend HostName = tostring(split(Computer, ".")[0]), DomainIndex = toint(indexof(Computer, '.'))
| extend HostNameDomain = iff(DomainIndex != -1, substring(Computer, DomainIndex + 1), Computer)
| project-away DomainIndex

Analytic Rule Definition

id: a35f2c18-1b97-458f-ad26-e033af18eb99
name: User account added to built in domain local or global group
description: |
  'Identifies when a user account has been added to a privileged built in domain local group or global group such as the Enterprise Admins, Cert Publishers or DnsAdmins. Be sure to verify this is an expected addition.'
severity: Low
requiredDataConnectors:
  - connectorId: SecurityEvents
    dataTypes:
      - SecurityEvent
  - connectorId: WindowsSecurityEvents
    dataTypes:
      - SecurityEvent
  - connectorId: WindowsForwardedEvents
    dataTypes:
      - WindowsEvent
queryFrequency: 1d
queryPeriod: 1d
triggerOperator: gt
triggerThreshold: 0
tactics:
  - Persistence
  - PrivilegeEscalation
relevantTechniques:
  - T1098
  - T1078
query: |
  // For AD SID mappings - https://docs.microsoft.com/windows/security/identity-protection/access-control/active-directory-security-groups
  let WellKnownLocalSID = "S-1-5-32-5[0-9][0-9]$";
  let WellKnownGroupSID = "S-1-5-21-[0-9]*-[0-9]*-[0-9]*-5[0-9][0-9]$|S-1-5-21-[0-9]*-[0-9]*-[0-9]*-1102$|S-1-5-21-[0-9]*-[0-9]*-[0-9]*-1103$|S-1-5-21-[0-9]*-[0-9]*-[0-9]*-498$|S-1-5-21-[0-9]*-[0-9]*-[0-9]*-1000$";
  union isfuzzy=true
  (
  SecurityEvent
  // 4728 - A member was added to a security-enabled global group
  // 4732 - A member was added to a security-enabled local group
  // 4756 - A member was added to a security-enabled universal group
  | where EventID in (4728, 4732, 4756)
  | where AccountType == "User"
  | where TargetSid matches regex WellKnownLocalSID or TargetSid matches regex WellKnownGroupSID
  // Exclude Remote Desktop Users group: S-1-5-32-555
  | where TargetSid !in ("S-1-5-32-555")
  | extend SimpleMemberName = iff(MemberName == "-", MemberName, substring(MemberName, 3, indexof_regex(MemberName, @",OU|,CN") - 3))
  | project TimeGenerated, EventID, Activity, Computer, SimpleMemberName, MemberName, MemberSid, TargetAccount, TargetUserName, TargetDomainName, TargetSid, UserPrincipalName, 
  SubjectAccount, SubjectUserName, SubjectDomainName, SubjectUserSid
  ),
  (
  WindowsEvent
  // 4728 - A member was added to a security-enabled global group
  // 4732 - A member was added to a security-enabled local group
  // 4756 - A member was added to a security-enabled universal group
  | where EventID in (4728, 4732, 4756) and not(EventData has "S-1-5-32-555")
  | extend SubjectUserSid = tostring(EventData.SubjectUserSid)
  | extend Account =  strcat(tostring(EventData.SubjectDomainName),"\\", tostring(EventData.SubjectUserName))
  | extend AccountType=case(Account endswith "$" or SubjectUserSid in ("S-1-5-18", "S-1-5-19", "S-1-5-20"), "Machine", isempty(SubjectUserSid), "", "User")
  | extend MemberName = tostring(EventData.MemberName)
  | where AccountType == "User"
  | extend TargetSid = tostring(EventData.TargetSid)
  | where TargetSid matches regex WellKnownLocalSID or TargetSid matches regex WellKnownGroupSID
  // Exclude Remote Desktop Users group: S-1-5-32-555
  | where Targe

Required Data Sources

MITRE ATT&CK Context

• Tactic: Persistence
• Tactic: PrivilegeEscalation
• Technique: T1098 — T1098
• Technique: T1078 — T1078

References

• Source Query

False Positive Guidance

• Scenario: Scheduled job runs with elevated privileges
  Description: A scheduled task or service account is added to a privileged group (e.g., Domain Admins) as part of an automated process to ensure it has the necessary permissions to execute scripts or access resources.
  Filter/Exclusion: Check the Subject field for known service accounts or scheduled task names (e.g., TaskScheduler or SQLAgent). Use a filter like:

  (SubjectUserSid == "S-1-5-80-123456789-...") or (ProcessName == "schtasks.exe")

• Scenario: Group Policy Object (GPO) update
  Description: A GPO is updated to add a user account to a built-in group (e.g., Cert Publishers) as part of a security configuration change.
  Filter/Exclusion: Filter events where the EventID is related to GPO processing (e.g., Event ID 100001 or 100002). Use a filter like:

  (EventID == 100001) or (EventID == 100002)

• Scenario: User account added via PowerShell script for administrative tasks
  Description: A PowerShell script is run by an admin to add a user to a built-in group (e.g., DNSAdmins) for a specific administrative task.
  Filter/Exclusion: Filter events where the ProcessName is powershell.exe and the command line includes Add-ADGroupMember or similar commands. Use a filter like:

  (ProcessName == "powershell.exe") and (CommandLine contains "Add-ADGroupMember")