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Description

The following analytic detects modifications to the Windows registry related to the Local Security Authority (LSA) NoLMHash setting. It identifies when the registry value is set to 0, indicating that the system will store passwords in the weaker Lan Manager (LM) hash format. This detection leverages registry activity logs from endpoint data sources like Sysmon or EDR tools. Monitoring this activity is crucial as it can indicate attempts to weaken password storage security. If confirmed malicious, this could allow attackers to exploit weaker LM hashes, potentially leading to unauthorized access and credential theft.

  • Type: TTP
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel: Endpoint
  • Last Updated: 2024-05-24
  • Author: Teoderick Contreras, Splunk
  • ID: 48cc1605-538c-4223-8382-e36bee5b540d

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1003.004 LSA Secrets Credential Access
Kill Chain Phase
  • Exploitation
NIST
  • DE.CM
CIS20
  • CIS 10
CVE 


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| tstats `security_content_summariesonly` count FROM datamodel=Endpoint.Registry WHERE (Registry.registry_path= "*\\System\\CurrentControlSet\\Control\\Lsa\\NoLMHash" Registry.registry_value_data = 0x00000000) BY _time span=1h Registry.dest Registry.user Registry.registry_path Registry.registry_key_name Registry.registry_value_name Registry.registry_value_data Registry.process_guid 
| `drop_dm_object_name(Registry)` 
| where isnotnull(registry_value_data) 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `windows_lsa_secrets_nolmhash_registry_filter`

Macros

The SPL above uses the following Macros:

:information_source: windows_lsa_secrets_nolmhash_registry_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
  • Registry.registry_path
  • Registry.registry_key_name
  • Registry.registry_value_name
  • Registry.registry_key_name
  • Registry.user
  • Registry.dest
  • Registry.action
  • Registry.registry_value_data
  • Registry.process_guid

How To Implement

To successfully implement this search, you must be ingesting data that records registry activity from your hosts to populate the endpoint data model in the registry node. This is typically populated via endpoint detection-and-response product, such as Carbon Black or endpoint data sources, such as Sysmon. The data used for this search is typically generated via logs that report reads and writes to the registry.

Known False Positives

Administrator may change this registry setting.

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
64.0 80 80 Windows LSA Secrets NoLMhash Registry on $dest$ by $user$.

: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