add rules by Daniel Bohannon

rules/windows/builtin/win_invoke_obfuscation_obfuscated_iex_services.yml

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+---
+action: global
+title: Invoke-Obfuscation obfuscated IEX invocation
+description: Detects all variations of obfuscated powershell IEX invocation code generated by Invoke-Obfuscation framework from the following code block — https://github.com/danielbohannon/Invoke-Obfuscation/blob/master/Out-ObfuscatedStringCommand.ps1#L873-L888
+status: experimental
+author: Daniel Bohannon (@Mandiant/@FireEye), oscd.community
+date: 2019/11/08
+tags:
+    - attack.defense_evasion
+    - attack.t1027
+falsepositives:
+    - Unknown
+level: high
+detection:
+    selection:
+        - ImagePath|re: '\$PSHome\[\s*\d{1,3}\s*\]\s*\+\s*\$PSHome\['
+        - ImagePath|re: '\$ShellId\[\s*\d{1,3}\s*\]\s*\+\s*\$ShellId\['
+        - ImagePath|re: '\$env:Public\[\s*\d{1,3}\s*\]\s*\+\s*\$env:Public\['
+        - ImagePath|re: '\$env:ComSpec\[(\s*\d{1,3}\s*,){2}'
+        - ImagePath|re: '\*mdr\*\W\s*\)\.Name'
+        - ImagePath|re: '\$VerbosePreference\.ToString\('
+        - ImagePath|re: '\String\]\s*\$VerbosePreference'
+    condition: selection
+---
+logsource:
+    product: windows
+    service: system
+detection:
+    selection:
+        EventID: 7045
+---
+logsource:
+    product: windows
+    service: sysmon
+detection:
+    selection:
+        EventID: 6
+---
+ logsource:
+     product: windows
+     service: security
+ detection:
+     selection:
+         EventID: 4697

rules/windows/powershell/powershell_invoke_obfuscation_obfuscated_iex.yml

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+title: Invoke-Obfuscation obfuscated IEX invocation
+description: Detects all variations of obfuscated powershell IEX invocation code generated by Invoke-Obfuscation framework from the following code block — https://github.com/danielbohannon/Invoke-Obfuscation/blob/master/Out-ObfuscatedStringCommand.ps1#L873-L888
+status: experimental
+author: Daniel Bohannon (@Mandiant/@FireEye), oscd.community
+date: 2019/11/08
+tags:
+    - attack.defense_evasion
+    - attack.t1027
+logsource:
+    product: windows
+    service: powershell
+detection:
+    selection_1:
+        EventID: 4104
+    selection_2:
+        - ScriptBlockText|re: '\$PSHome\[\s*\d{1,3}\s*\]\s*\+\s*\$PSHome\['
+        - ScriptBlockText|re: '\$ShellId\[\s*\d{1,3}\s*\]\s*\+\s*\$ShellId\['
+        - ScriptBlockText|re: '\$env:Public\[\s*\d{1,3}\s*\]\s*\+\s*\$env:Public\['
+        - ScriptBlockText|re: '\$env:ComSpec\[(\s*\d{1,3}\s*,){2}'
+        - ScriptBlockText|re: '\*mdr\*\W\s*\)\.Name'
+        - ScriptBlockText|re: '\$VerbosePreference\.ToString\('
+        - ScriptBlockText|re: '\String\]\s*\$VerbosePreference'
+    selection_3:
+        EventID: 4103
+    selection_4:
+        - Payload|re: '\$PSHome\[\s*\d{1,3}\s*\]\s*\+\s*\$PSHome\['
+        - Payload|re: '\$ShellId\[\s*\d{1,3}\s*\]\s*\+\s*\$ShellId\['
+        - Payload|re: '\$env:Public\[\s*\d{1,3}\s*\]\s*\+\s*\$env:Public\['
+        - Payload|re: '\$env:ComSpec\[(\s*\d{1,3}\s*,){2}'
+        - Payload|re: '\*mdr\*\W\s*\)\.Name'
+        - Payload|re: '\$VerbosePreference\.ToString\('
+        - Payload|re: '\String\]\s*\$VerbosePreference'
+    condition: ( selection_1 and selection_2 ) or ( selection_3 and selection_4 )
+falsepositives:
+    - Unknown
+level: high

rules/windows/process_creation/win_invoke_obfuscation_obfuscated_iex_commandline.yml

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+title: Invoke-Obfuscation obfuscated IEX invocation
+description: Detects all variations of obfuscated powershell IEX invocation code generated by Invoke-Obfuscation framework from the following code block — https://github.com/danielbohannon/Invoke-Obfuscation/blob/master/Out-ObfuscatedStringCommand.ps1#L873-L888
+status: experimental
+author: Daniel Bohannon (@Mandiant/@FireEye), oscd.community
+date: 2019/11/08
+tags:
+    - attack.defense_evasion
+    - attack.t1027
+logsource:
+    product: windows
+    service: process_creation
+detection:
+    selection:
+        - CommandLine|re: '\$PSHome\[\s*\d{1,3}\s*\]\s*\+\s*\$PSHome\['
+        - CommandLine|re: '\$ShellId\[\s*\d{1,3}\s*\]\s*\+\s*\$ShellId\['
+        - CommandLine|re: '\$env:Public\[\s*\d{1,3}\s*\]\s*\+\s*\$env:Public\['
+        - CommandLine|re: '\$env:ComSpec\[(\s*\d{1,3}\s*,){2}'
+        - CommandLine|re: '\*mdr\*\W\s*\)\.Name'
+        - CommandLine|re: '\$VerbosePreference\.ToString\('
+        - CommandLine|re: '\String\]\s*\$VerbosePreference'
+    condition: selection
+falsepositives:
+    - Unknown
+level: high