AN0388
Analytic 0388
Windows
Execution of InstallUtil.exe from .NET framework directories with arguments specifying non-standard or attacker-supplied assemblies, especially when followed by suspicious child process creation or script execution. Detection also includes correlation of newly created binaries prior to InstallUtil invocation and anomalous command-line usage compared to historical baselines.
WinEventLog:PowerShell
EventCode=4103, 4104, 4105, 4106
WinEventLog:Sysmon
EventCode=1
WinEventLog:Sysmon
EventCode=11
WinEventLog:Sysmon
EventCode=7
[InstallUtilPathRegex]
Regex pattern for InstallUtil.exe in .NET directories; tune to exclude known good administrative scripts
[AssemblyPathRegex]
Patterns for identifying suspicious assemblies (e.g., in temp folders, user profiles)
[ChildProcessList]
List of suspicious child processes spawned from InstallUtil.exe (e.g., cmd.exe, powershell.exe, rundll32.exe)
[TimeWindow]
Time correlation window between file creation of assembly and its execution via InstallUtil.exe