Create Remote Thread into LSASS
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 EventID 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.
Query · spl
`sysmon`
EventID=8
TargetImage="*\\lsass.exe"
| stats count min(_time) as firstTime
max(_time) as lastTime
values(NewThreadId) as "NewThreadId"
values(StartAddress) as "StartAddress"
by dest signature_id signature
SourceProcessGuid SourceProcessId SourceImage
TargetProcessGuid TargetProcessId TargetImage
StartModule StartFunction vendor_product
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)`
| `create_remote_thread_into_lsass_filter`
Implementation guide
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.
Analyst notes
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.