| description |
|---|
UAC Bypass/Defense Evasion, Persistence |
The Microsoft Component Object Model (COM) is a platform-independent, distributed, object-oriented system for creating binary software components that can interact. COM is the foundation technology for Microsoft's OLE (compound documents), ActiveX (Internet-enabled components), as well as others.
In this lab we will execute a file-less UAC bypass technique.
On the compromised system, change the HKEY_LOCAL_MACHINE\SOFTWARE\Classes\mscfile\shell\open\command default value to point to your binary. In this case I chose powershell.exe:
By default, launching Windows Event Viewer calls under the hood:"C:\Windows\system32\mmc.exe" "C:\Windows\system32\eventvwr.msc" /s
Since we hijacked the HKEY_LOCAL_MACHINE\SOFTWARE\Classes\mscfile\shell\open\command to point to powershell, when launching Even Viewer, the powershell is invoked instead:
Monitoring registry for changes in HKEY_CLASSES_ROOT\mscfile\shell\open\command can reveal this hijaking activity:
{% embed url="https://attack.mitre.org/wiki/Technique/T1122" %}
{% embed url="https://enigma0x3.net/2016/08/15/fileless-uac-bypass-using-eventvwr-exe-and-registry-hijacking/" %}
{% embed url="https://www.greyhathacker.net/?p=796" %}
{% embed url="http://www.fuzzysecurity.com/tutorials/27.html" %}