Detection: Detect Critical Alerts from Security Tools

Description

The following analytics is to detect high and critical alerts from endpoint security tools such as Microsoft Defender, Carbon Black, and Crowdstrike. This query aggregates and summarizes critical severity alerts from the Alerts data model, providing details such as the alert signature, application, description, source, destination, and timestamps, while applying custom filters and formatting for enhanced analysis in a SIEM environment.This capability allows security teams to efficiently allocate resources and maintain a strong security posture, while also supporting compliance with regulatory requirements by providing a clear record of critical security events. We tested these detections with logs from Microsoft Defender, however this detection should work for any security alerts that are ingested into the alerts data model. Note - We are dynamically creating the risk_score field based on the severity of the alert in the SPL and that supersedes the risk score set in the detection.

Search

1
2| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime values(Alerts.description) as description values(Alerts.mitre_technique_id) as annotations.mitre_attack.mitre_technique_id values(Alerts.severity) as severity values(Alerts.type) as type values(Alerts.severity_id) as severity_id values(Alerts.signature) as signature values(Alerts.signature_id) as signature_id values(Alerts.dest) as dest from datamodel=Alerts where  Alerts.severity IN ("high","critical") by Alerts.src Alerts.user Alerts.id Alerts.vendor sourcetype 
3| `drop_dm_object_name("Alerts")` 
4| `security_content_ctime(firstTime)` 
5| `security_content_ctime(lastTime)` 
6| eval risk_score=case(severity="informational", 2, severity="low", 5, severity="medium", 10, severity="high", 50, severity="critical" , 100) 
7| `detect_critical_alerts_from_security_tools_filter`

Data Source

Name	Platform	Sourcetype	Source
MS365 Defender Incident Alerts	N/A	'ms365:defender:incident:alerts'	'ms365_defender_incident_alerts'
Windows Defender Alerts	Windows	'mscs:azure:eventhub:defender:advancedhunting'	'eventhub://windowsdefenderlogs'

Macros Used

Annotations

Default Configuration

This detection is configured by default in Splunk Enterprise Security to run with the following settings:

Implementation

In order to properly run this search, you to ingest alerts data from other security products such as Crowdstrike, Microsoft Defender, or Carbon Black using appropriate TAs for that technology. Once ingested, the fields should be mapped to the Alerts data model. Make sure to apply transformation on the data if necessary. The risk_score field is used to calculate the risk score for the alerts and the mitre_technique_id field is used to map the alerts to the MITRE ATT&CK framework is dynamically created by the detection when this is triggered. These fields need not be set in the adaptive response actions.

Known False Positives

False positives may vary by endpoint protection tool; monitor and filter out the alerts that are not relevant to your environment.

Associated Analytic Story

• Critical Alerts

Risk Based Analytics (RBA)

References

• https://techcommunity.microsoft.com/t5/microsoft-defender-for-cloud/accessing-microsoft-defender-for-cloud-alerts-in-splunk-using/ba-p/938228

• https://docs.splunk.com/Documentation/CIM/5.3.2/User/Alerts

• https://learn.microsoft.com/en-us/defender-endpoint/api/raw-data-export-event-hub

Detection Testing

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

Source: GitHub | Version: 1