Added rule to detect clearing of event logs via dotnet class

rules/windows/powershell/powershell_script/posh_ps_susp_clear_eventlog.yml

@@ -9,8 +9,12 @@ references:
     - https://twitter.com/oroneequalsone/status/1568432028361830402
     - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1070.001/T1070.001.md
     - https://eqllib.readthedocs.io/en/latest/analytics/5b223758-07d6-4100-9e11-238cfdd0fe97.html
-author: Nasreddine Bencherchali (Nextron Systems)
+    - https://stackoverflow.com/questions/66011412/how-to-clear-a-event-log-in-powershell-7
+    - https://learn.microsoft.com/en-us/dotnet/api/system.diagnostics.eventing.reader.eventlogsession.clearlog?view=windowsdesktop-9.0&viewFallbackFrom=dotnet-plat-ext-5.0#System_Diagnostics_Eventing_Reader_EventLogSession_ClearLog_System_String_
+    - https://learn.microsoft.com/en-us/dotnet/api/system.diagnostics.eventlog.clear
+author: Nasreddine Bencherchali (Nextron Systems), Swachchhanda Shrawan Poudel (Nextron Systems)
 date: 2022-09-12
+modified: 2025-03-12
 tags:
     - attack.defense-evasion
     - attack.t1070.001
@@ -20,11 +24,17 @@ logsource:
     definition: 'Requirements: Script Block Logging must be enabled'
 detection:
     selection:
-        ScriptBlockText|contains:
-            - 'Clear-EventLog '
-            - 'Remove-EventLog '
-            - 'Limit-EventLog '
-            - 'Clear-WinEvent '
+        - ScriptBlockText|contains:
+              - 'Clear-EventLog '
+              - 'Remove-EventLog '
+              - 'Limit-EventLog '
+              - 'Clear-WinEvent '
+        - ScriptBlockText|contains|all:
+              - 'Eventing.Reader.EventLogSession' # [System.Diagnostics.Eventing.Reader.EventLogSession]::GlobalSession.ClearLog($_.LogName)
+              - 'ClearLog'
+        - ScriptBlockText|contains:
+              - 'Diagnostics.EventLog'
+              - 'Clear'
     condition: selection
 falsepositives:
     - Rare need to clear logs before doing something. Sometimes used by installers or cleaner scripts. The script should be investigated to determine if it's legitimate

rules/windows/process_creation/proc_creation_win_susp_eventlog_clear.yml

@@ -10,9 +10,13 @@ references:
     - https://learn.microsoft.com/en-us/windows-server/administration/windows-commands/wevtutil
     - https://gist.github.com/fovtran/ac0624983c7722e80a8f5a4babb170ee
     - https://jdhnet.wordpress.com/2017/12/19/changing-the-location-of-the-windows-event-logs/
-author: Ecco, Daniil Yugoslavskiy, oscd.community, D3F7A5105
+    - https://www.linkedin.com/posts/huntress-labs_when-a-sketchy-incident-hits-your-network-activity-7304940371078238208-Th_l/?utm_source=share&utm_medium=member_desktop&rcm=ACoAAAJTlRcB28IaUtg03HUU-IdliwzoAL1flGc
+    - https://stackoverflow.com/questions/66011412/how-to-clear-a-event-log-in-powershell-7
+    - https://learn.microsoft.com/en-us/dotnet/api/system.diagnostics.eventing.reader.eventlogsession.clearlog?view=windowsdesktop-9.0&viewFallbackFrom=dotnet-plat-ext-5.0#System_Diagnostics_Eventing_Reader_EventLogSession_ClearLog_System_String_
+    - https://learn.microsoft.com/en-us/dotnet/api/system.diagnostics.eventlog.clear
+author: Ecco, Daniil Yugoslavskiy, oscd.community, D3F7A5105, Swachchhanda Shrawan Poudel (Nextron Systems)
 date: 2019-09-26
-modified: 2023-07-13
+modified: 2025-03-12
 tags:
     - attack.defense-evasion
     - attack.t1070.001
@@ -22,38 +26,49 @@ logsource:
     category: process_creation
     product: windows
 detection:
-    selection_wevtutil:
-        Image|endswith: '\wevtutil.exe'
+    selection_wevtutil_img:
+        - Image|endswith: '\wevtutil.exe'
+        - OriginalFileName: 'wevtutil.exe'
+    selection_wevtutil_cmd:
         CommandLine|contains:
             - 'clear-log '          # clears specified log
             - ' cl '                # short version of 'clear-log'
             - 'set-log '            # modifies config of specified log. could be uset to set it to a tiny size
             - ' sl '                # short version of 'set-log'
             - 'lfn:'                # change log file location and name
-    selection_other_ps:
+    selection_other_ps_img:
         Image|endswith:
             - '\powershell.exe'
+            - '\powershell_ise.exe'
             - '\pwsh.exe'
-        CommandLine|contains:
-            - 'Clear-EventLog '
-            - 'Remove-EventLog '
-            - 'Limit-EventLog '
-            - 'Clear-WinEvent '
+    selection_other_ps_cmd:
+        - CommandLine|contains:
+              - 'Clear-EventLog '
+              - 'Remove-EventLog '
+              - 'Limit-EventLog '
+              - 'Clear-WinEvent '
+        - CommandLine|contains|all:
+              - 'Eventing.Reader.EventLogSession' # [System.Diagnostics.Eventing.Reader.EventLogSession]::GlobalSession.ClearLog($_.LogName)
+              - 'ClearLog'
+        - CommandLine|contains|all:
+              - 'Diagnostics.EventLog'
+              - 'Clear'
     selection_other_wmi:
         Image|endswith:
             - '\powershell.exe'
+            - '\powershell_ise.exe'
             - '\pwsh.exe'
             - '\wmic.exe'
         CommandLine|contains: 'ClearEventLog'
-    filter_msiexec:
+    filter_main_msiexec:
         # Example seen during office update/installation:
         #   ParentImage: C:\Windows\SysWOW64\msiexec.exe
         #   CommandLine: "C:\WINDOWS\system32\wevtutil.exe" sl Microsoft-RMS-MSIPC/Debug /q:true /e:true /l:4 /rt:false
         ParentImage:
             - 'C:\Windows\SysWOW64\msiexec.exe'
             - 'C:\Windows\System32\msiexec.exe'
         CommandLine|contains: ' sl '
-    condition: 1 of selection_* and not 1 of filter_*
+    condition: (all of selection_wevtutil_*) or (all of selection_other_ps_*) or (selection_other_wmi) and not 1 of filter_main_*
 falsepositives:
     - Admin activity
     - Scripts and administrative tools used in the monitored environment