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Description

The following analytic detects the creation of a remote thread in the Local Security Authority Subsystem Service (LSASS), which is a common tactic used by adversaries to steal user authentication credentials, known as credential dumping. The detection is made by leveraging Sysmon Event ID 8 logs and searches for processes that create remote threads in lsass.exe. This is an unusual activity that is generally linked to credential theft or credential dumping, which is a significant threat to network security. The detection is important because it helps to detect potential credential dumping attacks, which can result in significant damage to an organization's security. False positives might occur though the confidence level of this alert is high. There might be cases where legitimate tools can access LSASS and generate similar logs. Therefore, you must understand the broader context of such events and differentiate between legitimate activities and possible threats.

  • Type: TTP

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

  • Last Updated: 2019-12-06
  • 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

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