The following analytic is designed to detect potentially malicious activities involving the Local Security Authority Subsystem Service (LSASS) process. Specifically, it identifies when the LSASS process memory is being dumped, an action often associated with credential dumping attacks. This analytic leverages Sysmon logs, particularly those with EventCode 10 related to lsass.exe. It searches for indicators of LSASS memory dumping, such as specific call traces to dbgcore.dll and dbghelp.dll. While memory dumps can be legitimate administrative tasks, LSASS memory dumps are typically unusual and warrant investigation. To implement this analytic, ensure your Sysmon setup includes EventCode 10 logging for lsass.exe and customize the provided macros (sysmon and post-filter macro) to match your specific Splunk environment configuration.
- Type: TTP
Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Last Updated: 2019-12-06
- Author: Patrick Bareiss, Splunk
- ID: fb4c31b0-13e8-4155-8aa5-24de4b8d6717
Kill Chain Phase
- CIS 10
1 2 3 4 5 6 `sysmon` EventCode=10 TargetImage=*lsass.exe CallTrace=*dbgcore.dll* OR CallTrace=*dbghelp.dll* | stats count min(_time) as firstTime max(_time) as lastTime by Computer, TargetImage, TargetProcessId, SourceImage, SourceProcessId | rename Computer as dest | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `access_lsass_memory_for_dump_creation_filter`
The SPL above uses the following Macros:
access_lsass_memory_for_dump_creation_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
List of fields required to use this analytic.
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
Administrators can create memory dumps for debugging purposes, but memory dumps of the LSASS process would be unusual.
Associated Analytic Story
|63.0||70||90||process $SourceImage$ injected into $TargetImage$ and was attempted dump LSASS on $dest$. Adversaries tend to do this when trying to accesss credential material stored in the process memory of the Local Security Authority Subsystem Service (LSASS).|
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.
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