Windows Steal Authentication Certificates CS Backup

name: Windows Steal Authentication Certificates CS Backup
id: a2f4cc7f-6503-4078-b206-f83a29f408a7
version: 7
date: '2026-03-10'
author: Michael Haag, Splunk
status: production
type: Anomaly
description: The following analytic identifies the backup of the Active Directory Certificate Services (AD CS) store, detected via Event ID 4876. This event is logged when a backup is performed using the CertSrv.msc UI or the CertUtil.exe -BackupDB command. Monitoring this activity is crucial as unauthorized backups can indicate an attempt to steal authentication certificates, which are critical for secure communications. If confirmed malicious, this activity could allow an attacker to impersonate users, escalate privileges, or access sensitive information, severely compromising the security of the environment.
data_source:
    - Windows Event Log Security 4876
search: |-
    `wineventlog_security` EventCode=4876
      | stats count min(_time) as firstTime max(_time) as lastTime
        BY dest, name, action,
           Caller_Domain ,Caller_User_Name
      | `security_content_ctime(firstTime)`
      | `security_content_ctime(lastTime)`
      | `windows_steal_authentication_certificates_cs_backup_filter`
how_to_implement: To implement this analytic, enhanced Audit Logging must be enabled on AD CS and within Group Policy Management for CS server. See Page 128 of first reference.
known_false_positives: False positives will be generated based on normal certificate store backups. Leave enabled to generate Risk, as this is meant to be an anomaly analytic. If CS backups are not normal, enable as TTP.
references:
    - https://specterops.io/wp-content/uploads/sites/3/2022/06/Certified_Pre-Owned.pdf
drilldown_searches:
    - name: View the detection results for - "$dest$"
      search: '%original_detection_search% | search  dest = "$dest$"'
      earliest_offset: $info_min_time$
      latest_offset: $info_max_time$
    - name: View risk events for the last 7 days for - "$dest$"
      search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$dest$") 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: $info_max_time$
rba:
    message: The Active Directory Certiciate Services was backed up on $dest$.
    risk_objects:
        - field: dest
          type: system
          score: 20
    threat_objects: []
tags:
    analytic_story:
        - Windows Certificate Services
    asset_type: Endpoint
    mitre_attack_id:
        - T1649
    product:
        - Splunk Enterprise
        - Splunk Enterprise Security
        - Splunk Cloud
    security_domain: endpoint
tests:
    - name: True Positive Test
      attack_data:
        - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1649/atomic_red_team/4876_windows-security.log
          source: XmlWinEventLog:Security
          sourcetype: XmlWinEventLog