Crowdstrike Medium Severity Alert

SPLUNK detection rule by Teoderick Contreras, Splunk · Apache-2.0

The following analytic detects a CrowdStrike alert with MEDIUM severity indicates a potential threat that requires prompt attention. This alert level suggests suspicious activity that may compromise security but is not immediately critical. It typically involves detectable but non-imminent risks, such as unusual behavior or attempted policy violations, which should be investigated further and mitigated quickly to prevent escalation of attacks.

name: Crowdstrike Medium Severity Alert
id: 7e80d92a-6ec3-4eb1-a444-1480acfe2d14
version: 9
creation_date: '2024-07-31'
modification_date: '2026-05-13'
author: Teoderick Contreras, Splunk
status: production
type: Anomaly
description: The following analytic detects a CrowdStrike alert with MEDIUM severity indicates a potential threat that requires prompt attention. This alert level suggests suspicious activity that may compromise security but is not immediately critical. It typically involves detectable but non-imminent risks, such as unusual behavior or attempted policy violations, which should be investigated further and mitigated quickly to prevent escalation of attacks.
data_source: []
search: |-
    `crowdstrike_stream`
      | rename event.EndpointIp as src_ip, event.EndpointName as src_host, event.UserName as user, event.IncidentDescription as description, event.IncidentType as type, event.NumbersOfAlerts as count_alerts, event.SeverityName as severity
      | stats count min(_time) as firstTime max(_time) as lastTime
        BY src_ip, src_host, user,
           description, type, count_alerts,
           severity
      | where LIKE (severity, "%MEDIUM%")
      | `security_content_ctime(firstTime)`
      | `security_content_ctime(lastTime)`
      | `crowdstrike_medium_severity_alert_filter`
how_to_implement: To implement CrowdStrike stream JSON logs, use the Falcon Streaming API. Set up an API client, authenticate with your CrowdStrike credentials, and subscribe to the "CrowdStrike:Event:Streams:JSON" event stream. Process and store the JSON logs as needed, integrating them into your logging or SIEM system for monitoring and analysis.
known_false_positives: No false positives have been identified at this time.
references:
    - https://www.crowdstrike.com/wp-content/uploads/2022/12/CrowdStrike-Falcon-Event-Streams-Add-on-Guide-v3.pdf
drilldown_searches:
    - name: View the detection results for - "$user$"
      search: '%original_detection_search% | search  user = "$user$"'
      earliest_offset: $info_min_time$
      latest_offset: $info_max_time$
    - name: View risk events for the last 7 days for - "$user$"
      search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$user$") | stats count min(_time) as firstTime max(_time) as lastTime values(search_name) as "Search Name" values(risk_message) as "Risk Message" values(analyticstories) as "Analytic Stories" values(annotations._all) as "Annotations" values(annotations.mitre_attack.mitre_tactic) as "ATT&CK Tactics" by normalized_risk_object | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`'
      earliest_offset: 7d
      latest_offset: "0"
intermediate_findings:
    entities:
        - field: user
          type: user
          score: 20
          message: A MEDIUM Severity Crowdstrike Alert found in $src_host$
analytic_story:
    - Compromised Windows Host
asset_type: Endpoint
mitre_attack_id:
    - T1110
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: endpoint
security_domain: endpoint
tests:
    - name: True Positive Test
      attack_data:
        - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/suspicious_behaviour/crowdstrike_stream/medium_alert/crowdstrike_medium_clean.log
          sourcetype: CrowdStrike:Event:Streams:JSON
          source: CrowdStrike:Event:Streams
      description: PORTED MANUAL TEST - This detection is marked manual test because the attack_data file and TA do not provide the event.EndpointIp and event.EndpointName fields.  event.EndpointName is required to be present for the Risk Message Validation Integration Testing. This will be investigated and is a tracked issue.
      test_type: experimental

[[ currentRule.title && currentRule.title.length > 60 ? currentRule.title.slice(0, 60) + '…' : currentRule.title ]]

04e5d65e-b34c-4b4b-a201-b68f7e90c4f9

Propose edits, view related rules, and engage with the community through comments.

Executable code, not a declarative rule

This submission is arbitrary [[ currentRule.format ? currentRule.format.toUpperCase() : '' ]] code, not a declarative detection rule — review it as you would any script before running it, and note that it cannot be safely aggregated or auto-executed alongside YARA/Sigma/Suricata/CRS rules.

Rejected pattern present

[[ reason ]]

What does this mean?

Format & documentation suggestions

Not a security issue — this rule is valid and was accepted as-is. These are optional fields/conventions its own format recommends, mainly affecting its quality score and how well it documents itself for other reviewers.

[[ reason ]]

What do these messages mean?

[[ currentRule.title && currentRule.title.length > 60 ? currentRule.title.slice(0, 60) + '…' : currentRule.title ]]

[[ currentRule.title ]]

Community Discussion