LoFP / false positives may be present and filtering may need to occur based on organization endpoint behavior.

Techniques

• T1055

Sample rules

Notepad with no Command Line Arguments

• source: splunk
• technicques:
  • T1055

Description

The following analytic identifies behavior related to default SliverC2 framework where it will inject into Notepad.exe and spawn Notepad.exe with no command line arguments. In testing, this is a common procedure for SliverC2 usage, however may be modified or changed. From Microsoft, “The Sideload, SpawnDll, and Execute-Assembly commands spawn and inject into notepad.exe by default. The following query finds process creation events where the same process creates and injects into notepad.exe within 10 seconds.”

Detection logic

| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime FROM datamodel=Endpoint.Processes where Processes.process_name=notepad.exe AND Processes.action!="blocked" by host _time span=1h Processes.process_id Processes.process_name Processes.dest Processes.process_path Processes.process Processes.parent_process_name Processes.parent_process 
| `drop_dm_object_name(Processes)` 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| regex process="(?i)(notepad\.exe.{0,4}$)" 
| `notepad_with_no_command_line_arguments_filter`