Suspicious Use of CSharp Interactive Console

Severity: high
Author: Michael R. (@nahamike01)
Source: upstream

Detects the execution of CSharp interactive console by PowerShell

MITRE ATT&CK coverage

Tactic	Techniques
Defense Evasion	`T1127` Trusted Developer Utilities Proxy Execution

Event coverage

Provider	Event ID	Title
Sysmon	1	Process creation

Stages and Predicates

Stage 1: `selection`

or:
ParentImage|endswith: '\powershell.exe'
ParentImage|endswith: '\powershell_ise.exe'
ParentImage|endswith: '\pwsh.exe'
Image|endswith: '\csi.exe'
OriginalFileName: csi.exe

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.