The following analytic identifies renamed instances of
PsExec.exe being utilized on an endpoint. Most instances, it is highly probable to capture
Psexec.exe or other SysInternal utility usage with the command-line argument of
-accepteula. During triage, validate this is the legitimate version of
PsExec by reviewing the PE metadata. In addition, review parallel processes for further suspicious behavior.
- Type: Hunting
- Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Datamodel: Endpoint
- Last Updated: 2022-04-07
- Author: Michael Haag, Splunk
- ID: 683e6196-b8e8-11eb-9a79-acde48001122
Kill Chain Phase
- CIS 10
1 2 3 4 5 6 | tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where (Processes.process_name!=psexec.exe OR Processes.process_name!=psexec64.exe) AND Processes.original_file_name=psexec.c by Processes.dest Processes.user Processes.parent_process_name Processes.process_name Processes.process Processes.process_id Processes.parent_process_id Processes.original_file_name | `drop_dm_object_name(Processes)` | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `detect_renamed_psexec_filter`
The SPL above uses the following Macros:
detect_renamed_psexec_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
The detection is based on data that originates from Endpoint Detection and Response (EDR) agents. These agents are designed to provide security-related telemetry from the endpoints where the agent is installed. To implement this search, you must ingest logs that contain the process GUID, process name, and parent process. Additionally, you must ingest complete command-line executions. These logs must be processed using the appropriate Splunk Technology Add-ons that are specific to the EDR product. The logs must also be mapped to the
Processes node of the
Endpoint data model. Use the Splunk Common Information Model (CIM) to normalize the field names and speed up the data modeling process.
Known False Positives
Limited false positives should be present. It is possible some third party applications may use older versions of PsExec, filter as needed.
Associated Analytic Story
- SamSam Ransomware
- DHS Report TA18-074A
- HAFNIUM Group
- DarkSide Ransomware
- Active Directory Lateral Movement
- CISA AA22-320A
- Sandworm Tools
- BlackByte Ransomware
|27.0||30||90||The following $process_name$ has been identified as renamed, spawning from $parent_process_name$ on $dest$ by $user$.|
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.
source | version: 4