Attempt To Add Certificate To Untrusted Store

SPLUNK detection rule by Patrick Bareiss, Rico Valdez, Splunk · Apache-2.0

The following analytic detects attempts to add a certificate to the untrusted certificate store using the 'certutil -addstore' command. It leverages process activity and command-line arguments from Endpoint Detection and Response (EDR) logs mapped to the Splunk `Processes` data model. This activity is significant as it may indicate an attacker trying to disable security tools to gain unauthorized access. If confirmed malicious, this could lead to the compromise of system security, allowing attackers to bypass defenses and potentially escalate privileges or persist in the environment.

name: Attempt To Add Certificate To Untrusted Store
id: 6bc5243e-ef36-45dc-9b12-f4a6be131159
version: 20
creation_date: '2020-04-29'
modification_date: '2026-06-03'
author: Patrick Bareiss, Rico Valdez, Splunk
status: removed
deprecation_info:
    reason: Detection is deprecated as the usage of certutil and addstore by itself is not malicious.
    removed_in_version: 6.1.0
    replacement_content: []
type: Anomaly
description: |
    The following analytic detects attempts to add a certificate to the untrusted
    certificate store using the 'certutil -addstore' command.
    It leverages process activity and command-line arguments from Endpoint Detection and Response (EDR) logs mapped to the Splunk `Processes` data model.
    This activity is significant as it may indicate an attacker trying to disable security tools to gain unauthorized access.
    If confirmed malicious, this could lead to the compromise of system security, allowing attackers
    to bypass defenses and potentially escalate privileges or persist in the environment.
data_source:
    - Sysmon EventID 1
    - Windows Event Log Security 4688
    - CrowdStrike ProcessRollup2
search: |-
    | tstats `security_content_summariesonly` count min(_time) as firstTime values(Processes.process) as process max(_time) as lastTime FROM datamodel=Endpoint.Processes
      WHERE `process_certutil` (Processes.process=*-addstore*)
      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)`
    | `attempt_to_add_certificate_to_untrusted_store_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: There may be legitimate reasons for administrators to add a certificate to the untrusted certificate store. In such cases, this will typically be done on a large number of systems.
references:
    - https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1553.004/T1553.004.md
drilldown_searches:
    - name: View the detection results for - "$user$" and "$dest$"
      search: '%original_detection_search% | search  user = "$user$" dest = "$dest$"'
      earliest_offset: $info_min_time$
      latest_offset: $info_max_time$
    - name: View risk events for the last 7 days for - "$user$" and "$dest$"
      search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$user$", "$dest$") starthoursago=168  | 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: $info_min_time$
      latest_offset: $info_max_time$
intermediate_findings:
    entities:
        - field: user
          type: user
          score: 20
          message: An instance of $parent_process_name$ spawning $process_name$ was identified attempting to add a certificate to the store on endpoint $dest$ by user $user$.
        - field: dest
          type: system
          score: 20
          message: An instance of $parent_process_name$ spawning $process_name$ was identified attempting to add a certificate to the store on endpoint $dest$ by user $user$.
threat_objects:
    - field: parent_process_name
      type: parent_process_name
    - field: process_name
      type: process_name
analytic_story:
    - Disabling Security Tools
asset_type: Endpoint
mitre_attack_id:
    - T1553.004
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: deprecated
security_domain: endpoint
tests:
    - name: True Positive Test
      attack_data:
        - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1553.004/atomic_red_team/windows-sysmon.log
          source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
          sourcetype: XmlWinEventLog
      test_type: unit

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