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Description

this search is to detect a suspicious registry modification to implement auto admin logon to a host. This technique was seen in BlackMatter ransomware to automatically logon to the compromise host after triggering a safemode boot to continue encrypting the whole network. This behavior is not a common practice and really a suspicious TTP or alert need to be consider if found within then network premise.

  • Type: Anomaly
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel: Endpoint
  • Last Updated: 2021-09-06
  • Author: Teoderick Contreras, Splunk
  • ID: d4a3eb62-0f1e-11ec-a971-acde48001122

ATT&CK

ID Technique Tactic
T1552.002 Credentials in Registry Credential Access
T1552 Unsecured Credentials Credential Access

| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Registry where Registry.registry_path= "*SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion\\Winlogon*" AND Registry.registry_key_name= DefaultPassword OR Registry.registry_key_name= DefaultUserName by Registry.registry_path Registry.registry_key_name Registry.registry_value_name Registry.dest 
| `drop_dm_object_name(Registry)` 
| `security_content_ctime(firstTime)` 
|`security_content_ctime(lastTime)` 
| `add_defaultuser_and_password_in_registry_filter`

Associated Analytic Story

How To Implement

To successfully implement this search you need to be ingesting information on process that include the name of the process responsible for the changes from your endpoints into the Endpoint datamodel in the Registry node. Also make sure that this registry was included in your config files ex. sysmon config to be monitored.

Required field

  • _time
  • Registry.registry_path
  • Registry.registry_key_name
  • Registry.registry_value_name
  • Registry.dest

Kill Chain Phase

  • Exploitation

Known False Positives

unknown

RBA

Risk Score Impact Confidence Message
25.0 50 50 modified registry key $registry_key_name$ with registry value $registry_value_name$ to prepare autoadminlogon

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

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