Detection: Creation of lsass Dump with Taskmgr

Updated Date: 2024-11-13 ID: b2fbe95a-9c62-4c12-8a29-24b97e84c0cd Author: Michael Haag, Splunk Type: TTP Product: Splunk Enterprise Security

Description

The following analytic detects the creation of an lsass.exe process dump using Windows Task Manager. It leverages Sysmon EventID 11 to identify file creation events where the target filename matches lsass.dmp. This activity is significant because creating an lsass dump can be a precursor to credential theft, as the dump file contains sensitive information such as user passwords. If confirmed malicious, an attacker could use the lsass dump to extract credentials and escalate privileges, potentially compromising the entire network.

Search

1`sysmon` EventID=11 process_name=taskmgr.exe TargetFilename=*lsass*.dmp 
2| stats count min(_time) as firstTime max(_time) as lastTime by dest, object_category, process_name, TargetFilename  
3| `security_content_ctime(firstTime)` 
4| `security_content_ctime(lastTime)` 
5| `creation_of_lsass_dump_with_taskmgr_filter`

Data Source

Name	Platform	Sourcetype	Source
Sysmon EventID 11	Windows	`'xmlwineventlog'`	`'XmlWinEventLog:Microsoft-Windows-Sysmon/Operational'`

Macros Used

Name	Value
security_content_ctime	`convert timeformat="%Y-%m-%dT%H:%M:%S" ctime($field$)`
creation_of_lsass_dump_with_taskmgr_filter	`search *`

creation_of_lsass_dump_with_taskmgr_filter is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Annotations

- MITRE ATT&CK

+ Kill Chain Phases

+ NIST

+ CIS

- Threat Actors

ID	Technique	Tactic
T1003.001	LSASS Memory	Credential Access
T1003	OS Credential Dumping	Credential Access

Exploitation

DE.CM

CIS 10

Default Configuration

This detection is configured by default in Splunk Enterprise Security to run with the following settings:

Setting	Value
Disabled	true
Cron Schedule	`0 * * * *`
Earliest Time	`-70m@m`
Latest Time	`-10m@m`
Schedule Window	`auto`
Creates Notable	Yes
Rule Title	`%name%`
Rule Description	`%description%`
Notable Event Fields	user, dest
Creates Risk Event	True

This configuration file applies to all detections of type TTP. These detections will use Risk Based Alerting and generate Notable Events.

Implementation

This search requires Sysmon Logs and a Sysmon configuration, which includes EventCode 11 for detecting file create of lsass.dmp. 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

Risk Based Analytics (RBA)

Risk Message:

$process_name$ was identified on endpoint $dest$ writing $TargetFilename$ to disk. This behavior is related to dumping credentials via Task Manager.

Risk Object	Risk Object Type	Risk Score	Threat Objects
dest	system	80	No Threat Objects

References

Detection Testing

Test Type	Status	Dataset	Source	Sourcetype
Validation	✅ Passing	N/A	N/A	N/A
Unit	✅ Passing	Dataset	`XmlWinEventLog:Microsoft-Windows-Sysmon/Operational`	`XmlWinEventLog`
Integration	✅ Passing	Dataset	`XmlWinEventLog:Microsoft-Windows-Sysmon/Operational`	`XmlWinEventLog`

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: GitHub | Version: 4