Windows SQL Spawning CertUtil

name: Windows SQL Spawning CertUtil
id: dfc18a5a-946e-44ee-a373-c0f60d06e676
version: 14
creation_date: '2023-08-25'
modification_date: '2026-05-13'
author: Michael Haag, Splunk
status: experimental
type: TTP
description: The following analytic detects the use of certutil to download software, specifically when spawned by SQL-related processes. This detection leverages Endpoint Detection and Response (EDR) data, focusing on command-line executions involving certutil with parameters like *urlcache* and *split*. This activity is significant as it may indicate a compromise by threat actors, such as Flax Typhoon, who use certutil to establish persistent VPN connections. If confirmed malicious, this behavior could allow attackers to maintain access, monitor system availability, and potentially escalate to data theft or ransomware deployment.
data_source:
    - Sysmon EventID 1
    - Windows Event Log Security 4688
    - CrowdStrike ProcessRollup2
search: |-
    | tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime FROM datamodel=Endpoint.Processes
      WHERE Processes.parent_process_name IN ("sqlservr.exe", "sqlagent.exe", "sqlps.exe", "launchpad.exe", "sqldumper.exe") `process_certutil` (Processes.process="*urlcache*"
        OR
        Processes.process="*verifyctl*")
      BY Processes.action Processes.dest Processes.original_file_name
         Processes.parent_process Processes.parent_process_exec Processes.parent_process_guid
         Processes.parent_process_id Processes.parent_process_name Processes.parent_process_path
         Processes.process Processes.process_exec Processes.process_guid
         Processes.process_hash Processes.process_id Processes.process_integrity_level
         Processes.process_name Processes.process_path Processes.user
         Processes.user_id Processes.vendor_product
    | `drop_dm_object_name(Processes)`
    | `security_content_ctime(firstTime)`
    | `security_content_ctime(lastTime)`
    | `windows_sql_spawning_certutil_filter`
how_to_implement: The detection is based on data that originates from Endpoint Detection and Response (EDR) agents. These agents are designed to provide security-related telemetry from the endpoints where the agent is installed. To implement this search, you must ingest logs that contain the process GUID, process name, and parent process. Additionally, you must ingest complete command-line executions. These logs must be processed using the appropriate Splunk Technology Add-ons that are specific to the EDR product. The logs must also be mapped to the `Processes` node of the `Endpoint` data model. Use the Splunk Common Information Model (CIM) to normalize the field names and speed up the data modeling process.
known_false_positives: The occurrence of false positives should be minimal, given that the SQL agent does not typically download software using CertUtil.
references:
    - https://www.microsoft.com/en-us/security/blog/2023/08/24/flax-typhoon-using-legitimate-software-to-quietly-access-taiwanese-organizations/
finding:
    title: $process_name$ was launched on $dest$ by $user$. This behavior is uncommon with the SQL process identified.
    entity:
        field: user
        type: user
        score: 50
intermediate_findings:
    entities:
        - field: dest
          type: system
          score: 50
          message: $process_name$ was launched on $dest$ by $user$. This behavior is uncommon with the SQL process identified.
threat_objects:
    - field: process_name
      type: process_name
analytic_story:
    - SQL Server Abuse
    - Flax Typhoon
    - Storm-2460 CLFS Zero Day Exploitation
asset_type: Endpoint
mitre_attack_id:
    - T1105
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: endpoint
security_domain: endpoint