Dynamic CSharp Compile Artefact

calendar Feb 17, 2023 · attack.defense_evasion attack.t1027.004  ·
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When C# is compiled dynamically, a .cmdline file will be created as a part of the process. Certain processes are not typically observed compiling C# code, but can do so without touching disk. This can be used to unpack a payload for execution

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 1title: Dynamic CSharp Compile Artefact
 2id: e4a74e34-ecde-4aab-b2fb-9112dd01aed0
 3status: test
 4description: |
 5    When C# is compiled dynamically, a .cmdline file will be created as a part of the process.
 6    Certain processes are not typically observed compiling C# code, but can do so without touching disk.
 7    This can be used to unpack a payload for execution    
 8references:
 9    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1027.004/T1027.004.md#atomic-test-2---dynamic-c-compile
10author: frack113
11date: 2022/01/09
12modified: 2023/02/17
13tags:
14    - attack.defense_evasion
15    - attack.t1027.004
16logsource:
17    product: windows
18    category: file_event
19detection:
20    selection:
21        TargetFilename|endswith: '.cmdline'
22    condition: selection
23falsepositives:
24    - Unknown
25level: low

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