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detections/endpoint/windows_rasautou_dll_execution.yml

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+name: Windows Rasautou DLL Execution
+id: 6f42b8be-8e96-11ec-ad5a-acde48001122
+version: 1
+date: '2022-02-15'
+author: Michael Haag, Splunk
+type: TTP
+datamodel:
+- Endpoint
+description: The following analytic identifies the Windows Windows Remote Auto Dialer, rasautou.exe executing an arbitrary DLL. This technique is used to execute arbitrary shellcode or DLLs via the rasautou.exe LOLBin capability. 
+  During triage, review parent and child process behavior including file and image loads.
+search: '| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.process_name=rasautou.exe Processes.process="* -d *"AND Processes.process="* -p *" 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)` 
+  | `windows_rasautou_dll_execution_filter`'
+how_to_implement: To successfully implement this search you need to be ingesting information on process that include the name of the process responsible for the changes from your endpoints into the `Endpoint` datamodel in the `Processes` node. In addition, confirm the latest CIM App 4.20 or higher is installed and the latest TA for the endpoint product.
+known_false_positives: False positives will be limited to applications that require Rasautou.exe to load a DLL from disk. Filter as needed.
+references:
+  - https://github.com/mandiant/DueDLLigence
+  - https://github.com/MHaggis/notes/blob/master/utilities/Invoke-SPLDLLigence.ps1
+  - https://gist.github.com/NickTyrer/c6043e4b302d5424f701f15baf136513 
+  - https://www.fireeye.com/blog/threat-research/2019/10/staying-hidden-on-the-endpoint-evading-detection-with-shellcode.html
+tags:
+  analytic_story:
+  - Windows Defense Evasion Tactics
+  dataset:
+  - https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1055.001/rasautou/windows-sysmon.log
+  kill_chain_phases:
+  - Exploitation
+  mitre_attack_id:
+  - T1055.001
+  - T1218
+  - T1055
+  product:
+  - Splunk Enterprise
+  - Splunk Enterprise Security
+  - Splunk Cloud
+  required_fields:
+  - _time
+  - Processes.dest
+  - Processes.user
+  - Processes.parent_process_name #parent process name
+  - Processes.parent_process #parent cmdline
+  - Processes.original_file_name
+  - Processes.process_name #process name
+  - Processes.process #process cmdline
+  - Processes.process_id
+  - Processes.parent_process_path
+  - Processes.process_path
+  - Processes.parent_process_id
+  security_domain: endpoint
+  impact: 80
+  confidence: 100
+  # (impact * confidence)/100
+  risk_score: 80
+  context:
+  - Source:Endpoint
+  - Stage:Defense Evasion
+  message: An instance of $parent_process_name$ spawning $process_name$ was identified on endpoint $dest$ attempting to load a DLL in a suspicious manner.
+  observable:
+  - name: dest
+    type: Hostname
+    role:
+    - Victim
+  - name: parent_process_name
+    type: Parent Process
+    role:
+    - Parent Process
+  - name: process_name
+    type: Process
+    role:
+    - Child Process

tests/endpoint/windows_rasautou_dll_execution.test.yml

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+name: Windows Rasautou DLL Execution Unit Test
+tests:
+- name: Windows Rasautou DLL Execution
+  file: endpoint/windows_rasautou_dll_execution.yml
+  pass_condition: '| stats count | where count > 0'
+  earliest_time: '-24h'
+  latest_time: 'now'
+  attack_data:
+  - file_name: windows-sysmon.log
+    data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1055.001/rasautou/windows-sysmon.log
+    source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
+    sourcetype: xmlwineventlog