Try in Splunk Security Cloud

Description

This analytic is to detect a suspicious process terminating Lsass process. Lsass process is known to be a critical process that is responsible for enforcing security policy system. This process was commonly targetted by threat actor or red teamer to gain privilege escalation or persistence in the targeted machine because it handles credentials of the logon users. In this analytic we tried to detect a suspicious process having a granted access PROCESS_TERMINATE to lsass process to modify or delete protected registrys. This technique was seen in doublezero malware that tries to wipe files and registry in compromised hosts. This anomaly detection can be a good pivot of incident response for possible credential dumping or evading security policy in a host or network environment.

  • Type: Anomaly

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

  • Last Updated: 2023-04-14
  • Author: Teoderick Contreras, Splunk
  • ID: 7ab3c319-a4e7-4211-9e8c-40a049d0dba6

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1562.001 Disable or Modify Tools Defense Evasion
T1562 Impair Defenses Defense Evasion
Kill Chain Phase
  • Exploitation
NIST
  • DE.AE
CIS20
  • CIS 10
CVE 


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`sysmon` EventCode=10 TargetImage=*lsass.exe GrantedAccess = 0x1 
| stats count min(_time) as firstTime max(_time) as lastTime by SourceImage, TargetImage, TargetProcessId, SourceProcessId, GrantedAccess CallTrace, Computer 
| rename Computer as dest 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `windows_terminating_lsass_process_filter`

Macros

The SPL above uses the following Macros:

:information_source: windows_terminating_lsass_process_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
  • EventCode
  • TargetImage
  • CallTrace
  • Computer
  • TargetProcessId
  • SourceImage
  • SourceProcessId
  • GrantedAccess

How To Implement

This search requires Sysmon Logs and a Sysmon configuration, which includes EventCode 10 for 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

unknown

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
64.0 80 80 a process $SourceImage$ terminates Lsass process in $dest$

: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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