While conducting research on insecure Windows Communication Foundation (WCF) endpoints we stumbled upon SolarWinds fleet of products for two reasons; first, they have handful of software that you can test and secondly, most of the services were built using .NET Framework which makes it a strong candidate for our research.

​To continue our journey in the realm of bypassing UAC (see previous work here), we’ve decided to investigate Windows Server 2019. Please note this blog post is not a UAC primer but if you need to learn more about the subject, we think Wikipedia is a good place to start. The following is the process used to find a new UAC bypass in systemreset.exe binary using DLL Hijacking method. The technique was tested on Windows Server 2019 Version 1809 (OS Build 17763.404) and its still valid as of this writing.

**Update** - 5/23/2019
Please note Microsoft has released a behavioral detection for this attack vector in Windows Defender Antivirus with an alert level of “SEVERE."  We can confirm it works as expected. See the link here.
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Based on the increased interest in User Account Control (UAC) bypass research as of late, we've decided to read more on the subject and attempt to identify some sort of a pattern which ultimately led to finding our first UAC (still valid as of this writing) bypass. The following is a walkthrough of said finding. Please note we will not discuss UAC internals as there are plenty of well-written posts out there. In addition, will be using Windows 10 Version 1803 (OS Build 17134.590) as an example.