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Description

The following analytic identifies the use of the findstr command employed to search for unsecured credentials Group Policy Preferences (GPP). GPP are tools that allow administrators to create domain policies with embedded credentials. These policies allow administrators to set local accounts. These group policies are stored in SYSVOL on a domain controller. This means that any domain user can view the SYSVOL share and decrypt the password (using the AES key that has been made public). While Microsoft released a patch that impedes Administrators to create unsecure credentials, existing Group Policy Preferences files with passwords are not removed from SYSVOL.

  • Type: TTP

  • Product: Splunk Behavioral Analytics

  • Last Updated: 2023-05-02
  • Author: Mauricio Velazco, Splunk
  • ID: 73ed0f19-080e-4917-b7c6-56e1760a50d4

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1552 Unsecured Credentials Credential Access
T1552.006 Group Policy Preferences Credential Access
Kill Chain Phase
  • Exploitation
NIST
  • DE.CM
CIS20
  • CIS 10
CVE 


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 $main = from source  
| eval timestamp = time  
| eval metadata_uid = metadata.uid  
| eval process_pid = process.pid 
| eval process_file = process.file 
| eval process_file_path = process_file.path 
| eval process_file_name = lower(process_file.name) 
| eval process_cmd_line = process.cmd_line 
| eval actor_user = actor.user 
| eval actor_user_name = actor_user.name 
| eval actor_process = actor.process 
| eval actor_process_pid = actor_process.pid 
| eval actor_process_file = actor_process.file 
| eval actor_process_file_path = actor_process_file.path 
| eval actor_process_file_name = actor_process_file.name 
| eval device_hostname = device.hostname 
| where process_file_name="findstr.exe" AND process_cmd_line LIKE "%cpassword%" --finding_report--

Macros

The SPL above uses the following Macros:

:information_source: windows_findstr_gpp_discovery_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Required fields

List of fields required to use this analytic.

  • process.pid
  • process.file.path
  • process.file.name
  • process.cmd_line
  • actor.user.name
  • actor.process.pid
  • actor.process.file.path
  • actor.process.file.name
  • device.hostname

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

Administrators may leverage findstr to find passwords in GPO to validate exposure. Filter as needed.

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
56.0 70 80 Findstr was executed to discover GPP credentials on $dest$

:information_source: The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

Reference

Test Dataset

Replay any dataset to Splunk Enterprise by using our replay.py tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range

source | version: 4