github-actions[bot]
43 lines
1.9 KiB
YAML
43 lines
1.9 KiB
YAML
title: Powershell Token Obfuscation - Powershell
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id: f3a98ce4-6164-4dd4-867c-4d83de7eca51
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related:
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- id: deb9b646-a508-44ee-b7c9-d8965921c6b6
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type: similar
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status: test
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description: Detects TOKEN OBFUSCATION technique from Invoke-Obfuscation
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references:
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- https://github.com/danielbohannon/Invoke-Obfuscation
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author: frack113
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date: 2022/12/27
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modified: 2023/03/24
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tags:
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- attack.defense_evasion
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- attack.t1027.009
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logsource:
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product: windows
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category: ps_script
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definition: 'Requirements: Script Block Logging must be enabled'
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detection:
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selection:
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# Examples:
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# IN`V`o`Ke-eXp`ResSIOn (Ne`W-ob`ject Net.WebClient).DownloadString
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# &('In'+'voke-Expressi'+'o'+'n') (.('New-Ob'+'jec'+'t') Net.WebClient).DownloadString
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# &("{2}{3}{0}{4}{1}"-f 'e','Expression','I','nvok','-') (&("{0}{1}{2}"-f'N','ew-O','bject') Net.WebClient).DownloadString
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# ${e`Nv:pATh}
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- ScriptBlockText|re: '\w+`(\w+|-|.)`[\w+|\s]'
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# - ScriptBlockText|re: '\((\'(\w|-|\.)+\'\+)+\'(\w|-|\.)+\'\)' TODO: fixme
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- ScriptBlockText|re: '"(\{\d\}){2,}"\s*-f' # trigger on at least two placeholders. One might be used for legitimate string formatting
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- ScriptBlockText|re: '\$\{((e|n|v)*`(e|n|v)*)+:path\}|\$\{((e|n|v)*`(e|n|v)*)+:((p|a|t|h)*`(p|a|t|h)*)+\}|\$\{env:((p|a|t|h)*`(p|a|t|h)*)+\}'
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filter_chocolatey:
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ScriptBlockText|contains:
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- 'it will return true or false instead' # Chocolatey install script https://github.com/chocolatey/chocolatey
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- 'The function also prevents `Get-ItemProperty` from failing' # https://docs.chocolatey.org/en-us/create/functions/get-uninstallregistrykey
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filter_exchange:
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Path|startswith: 'C:\Program Files\Microsoft\Exchange Server\'
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Path|endswith: '\bin\servicecontrol.ps1'
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ScriptBlockText|contains: '`r`n'
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condition: selection and not 1 of filter_*
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falsepositives:
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- Unknown
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level: high
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