Detection rules › Splunk

Windows Findstr GPP Discovery

Status
production
Severity
medium
Group by
IntegrityLevel, command_line, computer_name, event_action, original_file_name, parent_command_line, parent_process_guid, parent_process_id, parent_process_name, process_guid, process_hash, process_id, process_name, user, user_id, vendor_product
Author
Mauricio Velazco, Splunk
Source
github.com/splunk/security_content

The following analytic detects the use of the findstr command to search for unsecured credentials in Group Policy Preferences (GPP). It leverages data from Endpoint Detection and Response (EDR) agents, focusing on command-line executions involving findstr.exe with references to SYSVOL and cpassword. This activity is significant because it indicates an attempt to locate and potentially decrypt embedded credentials in GPP, which could lead to unauthorized access. If confirmed malicious, this could allow an attacker to escalate privileges or gain access to sensitive systems and data within the domain.

MITRE ATT&CK coverage

Event coverage

Rule body splunk

name: Windows Findstr GPP Discovery
id: 1631ac2d-f2a9-42fa-8a59-d6e210d472f5
version: 12
creation_date: '2023-03-17'
modification_date: '2026-05-13'
author: Mauricio Velazco, Splunk
status: production
type: TTP
description: The following analytic detects the use of the findstr command to search for unsecured credentials in Group Policy Preferences (GPP). It leverages data from Endpoint Detection and Response (EDR) agents, focusing on command-line executions involving findstr.exe with references to SYSVOL and cpassword. This activity is significant because it indicates an attempt to locate and potentially decrypt embedded credentials in GPP, which could lead to unauthorized access. If confirmed malicious, this could allow an attacker to escalate privileges or gain access to sensitive systems and data within the domain.
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.process_name=findstr.exe
            AND
            Processes.process=*sysvol*
            AND
            Processes.process=*cpassword*
        )
      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_findstr_gpp_discovery_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: Administrators may leverage findstr to find passwords in GPO to validate exposure. Filter as needed.
references:
    - https://attack.mitre.org/techniques/T1552/006/
    - https://pentestlab.blog/2017/03/20/group-policy-preferences/
    - https://adsecurity.org/?p=2288
    - https://www.hackingarticles.in/credential-dumping-group-policy-preferences-gpp/
    - https://support.microsoft.com/en-us/topic/ms14-025-vulnerability-in-group-policy-preferences-could-allow-elevation-of-privilege-may-13-2014-60734e15-af79-26ca-ea53-8cd617073c30
drilldown_searches:
    - name: View the detection results for - "$dest$" and "$user$"
      search: '%original_detection_search% | search  dest = "$dest$" user = "$user$"'
      earliest_offset: $info_min_time$
      latest_offset: $info_max_time$
    - name: View risk events for the last 7 days for - "$dest$" and "$user$"
      search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$dest$", "$user$") | 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"
finding:
    title: Findstr was executed to discover GPP credentials on $dest$
    entity:
        field: user
        type: user
        score: 50
intermediate_findings:
    entities:
        - field: dest
          type: system
          score: 50
          message: Findstr was executed to discover GPP credentials on $dest$
analytic_story:
    - Active Directory Privilege Escalation
asset_type: Endpoint
mitre_attack_id:
    - T1552.006
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/T1552.006/findstr_gpp_discovery/windows-security.log
          source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
          sourcetype: XmlWinEventLog
      test_type: unit

Stages and Predicates

Stage 1: tstats

| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime FROM datamodel=Endpoint.Processes
  WHERE (
        Processes.process_name=findstr.exe
        AND
        Processes.process=*sysvol*
        AND
        Processes.process=*cpassword*
    )
  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

Stage 2: search

| `drop_dm_object_name(Processes)`

Stage 3: search

| `security_content_ctime(firstTime)`

Stage 4: search

| `security_content_ctime(lastTime)`

Stage 5: search

| `windows_findstr_gpp_discovery_filter`

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
Processes.processeq
  • "*cpassword*" corpus 2 (sigma 1, splunk 1)
  • "*sysvol*"
Processes.process_nameeq
  • "findstr.exe" corpus 2 (elastic 1, splunk 1)