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Description

The following analytic detects the creation of a remote thread in the Local Security Authority Subsystem Service (LSASS). This behavior is identified using Sysmon Event ID 8 logs, focusing on processes that create remote threads in lsass.exe. This activity is significant because it is commonly associated with credential dumping, a tactic used by adversaries to steal user authentication credentials. If confirmed malicious, this could allow attackers to gain unauthorized access to sensitive information, leading to potential compromise of the entire network. Analysts should investigate to differentiate between legitimate tools and potential threats.

  • Type: TTP

  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud

  • Last Updated: 2024-05-26
  • Author: Patrick Bareiss, Splunk
  • ID: 67d4dbef-9564-4699-8da8-03a151529edc

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1003.001 LSASS Memory Credential Access
T1003 OS Credential Dumping Credential Access
Kill Chain Phase
  • Exploitation
NIST
  • DE.CM
CIS20
  • CIS 10
CVE 


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`sysmon` EventID=8 TargetImage=*lsass.exe 
| stats count min(_time) as firstTime max(_time) as lastTime by dest, EventCode, TargetImage, TargetProcessId 
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)` 
| `create_remote_thread_into_lsass_filter`

Macros

The SPL above uses the following Macros:

:information_source: create_remote_thread_into_lsass_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
  • EventID
  • TargetImage
  • dest
  • EventCode
  • TargetImage
  • TargetProcessId
  • dest

How To Implement

This search needs Sysmon Logs with a Sysmon configuration, which includes EventCode 8 with lsass.exe. This search uses an input macro named sysmon. We strongly recommend that you specify your environment-specific configurations (index, source, sourcetype, etc.) for Windows Sysmon logs. Replace the macro definition with configurations for your Splunk environment. The search also uses a post-filter macro designed to filter out known false positives.

Known False Positives

Other tools can access LSASS for legitimate reasons and generate an event. In these cases, tweaking the search may help eliminate noise.

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
81.0 90 90 A process has created a remote thread into $TargetImage$ on $dest$. This behavior is indicative of credential dumping and should be investigated.

: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