Windows Renamed Powershell Execution
Description
The following analytic identifies instances where the PowerShell executable has been renamed and executed under an alternate filename. This behavior is commonly associated with attempts to evade security controls or bypass logging mechanisms that monitor standard PowerShell usage. While rare in legitimate environments, renamed PowerShell binaries are frequently observed in malicious campaigns leveraging Living-off-the-Land Binaries (LOLBins) and fileless malware techniques. This detection flags executions of PowerShell where the process name does not match the default powershell.exe or pwsh.exe, especially when invoked from unusual paths or accompanied by suspicious command-line arguments.
Query · spl
| tstats `security_content_summariesonly`
count min(_time) as firstTime
max(_time) as lastTime
from datamodel=Endpoint.Processes where
(
Processes.original_file_name = PowerShell.EXE
Processes.process_name != powershell.exe
)
OR
(
Processes.original_file_name = pwsh.dll
Processes.process_name != pwsh.exe
)
OR
(
Processes.original_file_name = powershell_ise.EXE
Processes.process_name != powershell_ise.exe
)
by Processes.action Processes.dest Processes.original_file_name Processes.parent_process
Processes.parent_process_exec Processes.parent_process_guid Processes.parent_process_id
Processes.parent_process_name Processes.parent_process_path Processes.process
Processes.process_exec Processes.process_guid Processes.process_hash Processes.process_id
Processes.process_integrity_level Processes.process_name Processes.process_path Processes.user
Processes.user_id Processes.vendor_product
| `drop_dm_object_name(Processes)`
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)`
| `windows_renamed_powershell_execution_filter`
Implementation guide
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
- No false positives have been identified at this time.
Analyst notes
Known false positives: No false positives have been identified at this time.