PH_Rule_SIGMA_245
Enabled
Detects scenarios where system auditing (ie: windows event log auditing) is disabled. This may be used in a scenario where an entity would want to bypass local logging to evade detection when windows event logging is enabled and reviewed. Also, it is recommended to turn off "Local Group Policy Object Processing" via GPO, which will make sure that Active Directory GPOs take precedence over local/edited computer policies via something such as "gpedit.msc". Please note, that disabling "Local Group Policy Object Processing" may cause an issue in scenarios of one off specific GPO modifications -- however it is recommended to perform these modifications in Active Directory anyways. . This rule is adapted from https://github.com/SigmaHQ/sigma/blob/master/rules/windows/builtin/security/win_security_disable_event_logging.yml
7
Security
Defense Evasion
Defense Evasion consists of techniques that adversaries use to avoid detection throughout their compromise. Techniques used for defense evasion include uninstalling/disabling security software or obfuscating/encrypting data and scripts. Adversaries also leverage and abuse trusted processes to hide and masquerade their malware. Other tactics’ techniques are cross-listed here when those techniques include the added benefit of subverting defenses.
https://attack.mitre.org/tactics/TA0005T1562.002
Impair Defenses: Disable Windows Event Logging
Adversaries may disable Windows event logging to limit data that can be leveraged for detections and audits.
https://attack.mitre.org/techniques/T1562/002Server
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="Win-Security-4719" AND actionName REGEXP ".*%%8448.*|.*%%8450.*"
This defines how matching events are aggregated, only events with the same matching attribute values are grouped into one unique incident ID
actionName,hostName
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
actionName = Filter.actionName,
hostName = Filter.hostName