SchCache Change By App Connect And Create ADSI Object

Description

The following analytic detects an application attempting to connect and create an ADSI object to perform an LDAP query. It leverages Sysmon EventCode 11 to identify changes in the Active Directory Schema cache files located in %LOCALAPPDATA%\Microsoft\Windows\SchCache or %systemroot%\SchCache. This activity is significant as it can indicate the presence of suspicious applications, such as ransomware, using ADSI object APIs for LDAP queries. If confirmed malicious, this behavior could allow attackers to gather sensitive directory information, potentially leading to further exploitation or lateral movement within the network.

Query · spl

`sysmon` EventCode=11 TargetFilename = "*\\Windows\\SchCache\\*" TargetFilename
    = "*.sch*" NOT (Image IN ("*\\Windows\\system32\\mmc.exe"))
| stats count min(_time)
    as firstTime max(_time) as lastTime by action dest file_name file_path process_guid
    process_id user_id vendor_product process_name
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)`
| `schcache_change_by_app_connect_and_create_adsi_object_filter`

Implementation guide

To successfully implement this search, you need to be ingesting logs with the process name, parent process, and command-line executions from your endpoints. If you are using Sysmon, you must have at least version 6.0.4 of the Sysmon TA.

Known false positives

  • normal application like mmc.exe and other ldap query tool may trigger this detections.

Analyst notes

Known false positives: normal application like mmc.exe and other ldap query tool may trigger this detections.

Raw source SchCache Change By App Connect And Create ADSI Object · SPL
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Published by splunk/security_content ↗, licensed under Apache 2.0 ↗. Reproduced here unmodified. 
name: SchCache Change By App Connect And Create ADSI Object
id: 991eb510-0fc6-11ec-82d3-acde48001122
version: 11
creation_date: '2021-09-08'
modification_date: '2026-05-13'
author: Teoderick Contreras, Splunk
status: production
type: Anomaly
description: The following analytic detects an application attempting to connect and create an ADSI object to perform an LDAP query. It leverages Sysmon EventCode 11 to identify changes in the Active Directory Schema cache files located in %LOCALAPPDATA%\Microsoft\Windows\SchCache or %systemroot%\SchCache. This activity is significant as it can indicate the presence of suspicious applications, such as ransomware, using ADSI object APIs for LDAP queries. If confirmed malicious, this behavior could allow attackers to gather sensitive directory information, potentially leading to further exploitation or lateral movement within the network.
data_source:
    - Sysmon EventID 11
search: |-
    `sysmon` EventCode=11 TargetFilename = "*\\Windows\\SchCache\\*" TargetFilename
        = "*.sch*" NOT (Image IN ("*\\Windows\\system32\\mmc.exe"))
    | stats count min(_time)
        as firstTime max(_time) as lastTime by action dest file_name file_path process_guid
        process_id user_id vendor_product process_name
    | `security_content_ctime(firstTime)`
    | `security_content_ctime(lastTime)`
    | `schcache_change_by_app_connect_and_create_adsi_object_filter`
how_to_implement: To successfully implement this search, you need to be ingesting logs with the process name, parent process, and command-line executions from your endpoints. If you are using Sysmon, you must have at least version 6.0.4 of the Sysmon TA.
known_false_positives: normal application like mmc.exe and other ldap query tool may trigger this detections.
references:
    - https://docs.microsoft.com/en-us/windows/win32/adsi/adsi-and-uac
    - https://news.sophos.com/en-us/2021/08/09/blackmatter-ransomware-emerges-from-the-shadow-of-darkside/
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 ("$dest$") | 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: dest
          type: system
          score: 20
          message: Process $process_name$ created a file $file_name$ on host $dest$
analytic_story:
    - BlackMatter Ransomware
asset_type: Endpoint
mitre_attack_id:
    - T1087.002
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/attack_techniques/T1087.002/blackmatter_schcache/windows-sysmon.log
          source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
          sourcetype: XmlWinEventLog
      test_type: unit

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