Invoke-Obfuscation Obfuscated IEX Invocation - PowerShell Module

calendar Nov 2, 2023 · attack.defense_evasion attack.t1027 attack.execution attack.t1059.001  ·
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Detects all variations of obfuscated powershell IEX invocation code generated by Invoke-Obfuscation framework from the code block cited in the reference section below

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 1title: Invoke-Obfuscation Obfuscated IEX Invocation - PowerShell Module
 2id: 2f211361-7dce-442d-b78a-c04039677378
 3related:
 4    - id: 1b9dc62e-6e9e-42a3-8990-94d7a10007f7
 5      type: derived
 6status: test
 7description: Detects all variations of obfuscated powershell IEX invocation code generated by Invoke-Obfuscation framework from the code block cited in the reference section below
 8references:
 9    - https://github.com/danielbohannon/Invoke-Obfuscation/blob/f20e7f843edd0a3a7716736e9eddfa423395dd26/Out-ObfuscatedStringCommand.ps1#L873-L888
10author: Daniel Bohannon (@Mandiant/@FireEye), oscd.community
11date: 2019/11/08
12modified: 2022/12/31
13tags:
14    - attack.defense_evasion
15    - attack.t1027
16    - attack.execution
17    - attack.t1059.001
18logsource:
19    product: windows
20    category: ps_module
21    definition: 0ad03ef1-f21b-4a79-8ce8-e6900c54b65b
22detection:
23    selection_payload:
24        - Payload|re: '\$PSHome\[\s*\d{1,3}\s*\]\s*\+\s*\$PSHome\['
25        - Payload|re: '\$ShellId\[\s*\d{1,3}\s*\]\s*\+\s*\$ShellId\['
26        - Payload|re: '\$env:Public\[\s*\d{1,3}\s*\]\s*\+\s*\$env:Public\['
27        - Payload|re: '\$env:ComSpec\[(\s*\d{1,3}\s*,){2}'
28        - Payload|re: '\*mdr\*\W\s*\)\.Name'
29        - Payload|re: '\$VerbosePreference\.ToString\('
30        - Payload|re: '\[String\]\s*\$VerbosePreference'
31    condition: selection_payload
32falsepositives:
33    - Unknown
34level: high

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