49 lines
1.5 KiB
YAML
49 lines
1.5 KiB
YAML
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title: Suspicious Csi.exe Usage
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author: Konstantin Grishchenko, oscd.community
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date: 2020/10/17
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description: Csi.exe is a signed binary from Microsoft that comes with Visual Studio
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and provides C# interactive capabilities. It can be used to run C# code from a file
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passed as a parameter in command line. Early version of this utility provided with
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Microsoft “Roslyn” Community Technology Preview was named 'rcsi.exe'
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detection:
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SELECTION_1:
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EventID: 1
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SELECTION_2:
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Image: '*\csi.exe'
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SELECTION_3:
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Image: '*\rcsi.exe'
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SELECTION_4:
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OriginalFileName: csi.exe
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SELECTION_5:
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OriginalFileName: rcsi.exe
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SELECTION_6:
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Company: Microsoft Corporation
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condition: (SELECTION_1 and (SELECTION_2 or SELECTION_3 or SELECTION_4 or SELECTION_5)
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and SELECTION_6)
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falsepositives:
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- Legitimate usage by software developers
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fields:
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- ComputerName
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- User
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- CommandLine
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- ParentCommandLine
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id: 40b95d31-1afc-469e-8d34-9a3a667d058e
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level: medium
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logsource:
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category: process_creation
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product: windows
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modified: 2021/05/11
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references:
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- https://github.com/LOLBAS-Project/LOLBAS/blob/master/yml/OtherMSBinaries/Csi.yml
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- https://github.com/LOLBAS-Project/LOLBAS/blob/master/yml/OtherMSBinaries/Rcsi.yml
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- https://enigma0x3.net/2016/11/21/bypassing-application-whitelisting-by-using-rcsi-exe/
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- https://twitter.com/Z3Jpa29z/status/1317545798981324801
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status: experimental
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tags:
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- attack.execution
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- attack.t1072
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- attack.defense_evasion
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- attack.t1218
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ruletype: SIGMA
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