A local security group's attributes were modified.
Modifications to local group descriptions or attributes are uncommon and may mask malicious groups.
Alert: changes outside business hours or by non-admin accounts.
SubjectUserNameTargetUserNameLogonTypeIpAddressWorkstationName Starting points — adapt the log source, projected fields and thresholds for your environment.
SecurityEvent
| where EventID == 4735 // A security-enabled local group was changed
| project TimeGenerated, Computer, SubjectUserName, TargetUserName, LogonType, IpAddress, WorkstationName
| sort by TimeGenerated descindex=* sourcetype="WinEventLog:Security" EventCode=4735
| stats count earliest(_time) as first_seen latest(_time) as last_seen by ComputerName
| sort - count `# A security-enabled local group was changed — add EventData fields: SubjectUserName, TargetUserName, LogonType, IpAddress`A security-enabled local group was changed. A local security group's attributes were modified.
Event 4735 is written to the Security channel by Microsoft-Windows-Security-Auditing. Advanced Audit Policy — enable the 'Account Management' subcategory (Success and/or Failure).
Alert: changes outside business hours or by non-admin accounts.