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Description

The following analytic detects the creation of a symlink to a shadow copy to identify potential threats earlier and mitigate the risks associated with symlink creation to shadow copies. The detection is made by using a Splunk query that searches for processes with commands containing "mklink" and "HarddiskVolumeShadowCopy". This analytic retrieves information such as the destination, user, process name, process ID, parent process, original file name, and parent process ID from the Endpoint.Processes data model. The detection is important because it indicates potential malicious activity since attackers might use this technique to manipulate or delete shadow copies, which are used for system backup and recovery. This detection helps to determine if an attacker is attempting to cover their tracks or prevent data recovery in the event of an incident. The impact of such an attack can be significant since it can hinder incident response efforts, prevent data restoration, and potentially lead to data loss or compromise. Next steps include reviewing the details of the process, such as the destination and the user responsible for creating the symlink. Additionally, you must examine the parent process, any relevant on-disk artifacts, and concurrent processes to identify the source of the attack.

  • Type: TTP
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel: Endpoint
  • Last Updated: 2021-09-16
  • Author: Patrick Bareiss, Splunk
  • ID: c5eac648-fae0-4263-91a6-773df1f4c903

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1003.003 NTDS Credential Access
T1003 OS Credential Dumping Credential Access
Kill Chain Phase
  • Exploitation
NIST
  • DE.CM
CIS20
  • CIS 10
CVE
1
2
3
4
5
6
| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where `process_cmd` Processes.process=*mklink* Processes.process=*HarddiskVolumeShadowCopy* by Processes.dest Processes.user Processes.process_name Processes.process  Processes.parent_process Processes.parent_process_name Processes.original_file_name Processes.process_id Processes.parent_process_id 
| `drop_dm_object_name(Processes)` 
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)` 
| `credential_dumping_via_symlink_to_shadow_copy_filter`

Macros

The SPL above uses the following Macros:

:information_source: credential_dumping_via_symlink_to_shadow_copy_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.

  • _time
  • Processes.dest
  • Processes.user
  • Processes.parent_process_name
  • Processes.parent_process
  • Processes.original_file_name
  • Processes.process_name
  • Processes.process
  • Processes.process_id
  • Processes.parent_process_path
  • Processes.process_path
  • Processes.parent_process_id

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

unknown

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
81.0 90 90 An instance of $parent_process_name$ spawning $process_name$ was identified on endpoint $dest$ by user $user$ attempting to create symlink to a shadow copy to grab credentials.

: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: 2