SigmaHQ/rules/windows/process_creation/win_susp_csi.yml

39 lines
1.4 KiB
YAML

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