splApache-2.0from splunk/security_content

Execution of File with Multiple Extensions

The following analytic detects the execution of files with multiple extensions, such as ".doc.exe" or ".pdf.exe". This behavior is identified using Endpoint Detection and Response (EDR) telemetry, focusing on process creation events where the file name contains double extensions. This activity is significant because attackers often use double extensions to disguise malicious executables as benign documents, increasing the likelihood of user execution. If confirmed malicious, this technique can lead to unauthorized code execution, potentially compromising the endpoint and allowing further malicious activities.

Quality

FP risk

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Rule sourcedetections/endpoint/execution_of_file_with_multiple_extensions.yml

| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime FROM datamodel=Endpoint.Processes
  WHERE Processes.process IN ("*.doc.exe", "*.xls.exe","*.ppt.exe", "*.htm.exe", "*.html.exe", "*.txt.exe", "*.pdf.exe", "*.docx.exe", "*.xlsx.exe", "*.pptx.exe","*.one.exe", "*.bat.exe", "*.rtf.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
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)`
| `drop_dm_object_name(Processes)`
| `execution_of_file_with_multiple_extensions_filter`