Chaining WireGuard VPN Servers on Windows (or “Double VPN”)

By | July 21, 2021

This tutorial goes through the process of setting up a VPN chain using WireGuard on Windows. There is a plenty of tutorials in the Internet devoted to “chaining” VPN servers, however most of them are Linux based and require certain technical skill. In the previous post we already learned how to setup WireGuard VPN Server on Windows and… Read More »

Securing Remote Desktop with SSH

By | March 29, 2020

Covid-19 led to a globe-wide work-from-home experiment and it is logical to expect the growing number of users accessing their computers remotely using Remote Desktop. Having an RDP port open to the Internet is generally considered insecure and most of the security experts advise using VPN or/and two-factor authentication to improve the security. Here we will review an… Read More »

“Failed to install WinpkFilter NDIS LWF driver with error 0x800700b7” or critical value of driver customization

By | January 22, 2018

One of our customers has recently reported that WinpkFilter installation has failed with error code 0x800700b7. This was the first report mentioning such error code and we have spend some time to research the issue at a customer side. Such behavior seems to be worth mentioning in a dedicated post. 0x800700b7 error code can be decoded as ERROR_ALREADY_EXISTS,… Read More »

Microsoft Edge and ProtectedHomepages

By | May 11, 2016

Recently I have had a small but curious research project with the requirement to decrypt ProtectedHomepages binary value stored under [HKEY_CURRENT_USER\Software\Classes\Local Settings\Software\Microsoft\Windows\CurrentVersion\AppContainer\Storage\microsoft.microsoftedge_8wekyb3d8bbwe\MicrosoftEdge\Protected – It is a violation of Windows Policy to modify. See aka.ms/browserpolicy]. While googling around the problem I have seen a related question on StackOverflow, so I decided that it may have sense to share the… Read More »

Windows Packet Filter and Gigabit networks

By | April 6, 2016

There is a very popular and important question about Windows Packet Filter: “Can I handle Gigabit traffic in WinpkFilter user-mode application without noticeable performance degradation?” I was asked quite often and usually my answer starts with “that depends…” followed up by various performance related considerations and ends with a sentence “if you need maximum possible performance then consider… Read More »

Inside PsExec remote administration

By | March 24, 2004

This is a short reverse engineering review of one useful remote administration utility originally authored by Mark Russinovich (you can download it from Microsoft web-site here). Original version of this review was published on this site in 2004, but since the utility is still very popular and users are interested about its internal design I decided to slightly… Read More »