PH_Rule_SIGMA_1163
Enabled
This detection uses Windows security events to detect suspicious access attempts to the registry key of Azure AD Health monitoring agent. This detection requires an access control entry (ACE) on the system access control list (SACL) of the following securable object HKLM\SOFTWARE\Microsoft\Microsoft Online\Reporting\MonitoringAgent. . This rule is adapted from https://github.com/SigmaHQ/sigma/blob/master/rules/windows/builtin/security/win_security_aadhealth_mon_agent_regkey_access.yml
5
Security
Discovery
Discovery consists of techniques an adversary may use to gain knowledge about the system and internal network. These techniques help adversaries observe the environment and orient themselves before deciding how to act. They also allow adversaries to explore what they can control and what’s around their entry point in order to discover how it could benefit their current objective. Native operating system tools are often used toward this post-compromise information-gathering objective.
https://attack.mitre.org/tactics/TA0007T1012
Query Registry
Adversaries may interact with the Windows Registry to gather information about the system, configuration, and installed software. Adversaries may use the information from Query Registry during automated discovery to shape follow-on behaviors, including whether or not the adversary fully infects the target and/or attempts specific actions.
https://attack.mitre.org/techniques/T1012Server
Windows Security Log via OMI or FortiSIEM Agent
Correlation
No remediation guidance specified
If the following pattern or patterns match an ingested event within the given time window in seconds, trigger an incident.
300 seconds
If the following defined pattern/s occur within a 300 second time window.
Filter
This is the named definition of the event query, this is important if multiple subpatterns are defined to distinguish them.
This is the query logic that matches incoming events
(eventType IN ("Win-Security-4656","Win-Security-4663") AND osObjType="Key" AND osObjName="\\REGISTRY\\MACHINE\\SOFTWARE\\Microsoft\\Microsoft Online\\Reporting\\MonitoringAgent") AND (procName NOT REGEXP ".*Microsoft\.Identity\.Health\.Adfs\.DiagnosticsAgent\.exe.*|.*Microsoft\.Identity\.Health\.Adfs\.InsightsService\.exe.*|.*Microsoft\.Identity\.Health\.Adfs\.MonitoringAgent\.Startup\.exe.*|.*Microsoft\.Identity\.Health\.Adfs\.PshSurrogate\.exe.*|.*Microsoft\.Identity\.Health\.Common\.Clients\.ResourceMonitor\.exe.*")
This defines how matching events are aggregated, only events with the same matching attribute values are grouped into one unique incident ID
hostName,osObjName,osObjType,procName
This is most typically a numerical constraint that defines when the rule should trigger an incident
COUNT(*) >= 1
This section defines which fields in matching raw events should be mapped to the incident attributes in the resulting incident.
The available raw event attributes to map are limited to the group by attributes and the aggregate event constraint fields for each subpattern
hostName = Filter.hostName,
osObjName = Filter.osObjName,
osObjType = Filter.osObjType,
procName = Filter.procName