The following analytic developed to detect potential credential dumping attacks where a remote thread is created in the Local Security Authority Subsystem Service (LSASS). Credential dumping, a common tactic used by adversaries to steal user authentication credentials, is a significant threat to network security. The analytic leverages Sysmon Event ID 8 logs and looks for processes creating remote threads in lsass.exe, an unusual activity generally linked to credential theft. The confidence level in this alert is high, but it's worth noting that there might be cases where legitimate tools can access LSASS, generating similar logs. As an analyst, it is critical to 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
Kill Chain Phase
- CIS 10
1 2 3 4 5 6 `sysmon` EventID=8 TargetImage=*lsass.exe | stats count min(_time) as firstTime max(_time) as lastTime by Computer, EventCode, TargetImage, TargetProcessId | rename Computer as dest | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `create_remote_thread_into_lsass_filter`
The SPL above uses the following Macros:
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.
List of fields required to use this analytic.
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
|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.|
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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