Double Pivots
Last updated
Last updated
In this case ww will have a Windows machine as jump host and then another windows machine on 172.16.5.19 and then a final machine on 172.16.6.155
is an example of a tool that uses Dynamic Virtual Channels (DVC) from the Remote Desktop Service feature of Windows.
DVC is responsible for tunneling packets over the RDP connection. Some examples of usage of this feature would be clipboard data transfer and audio sharing. However, this feature can also be used to tunnel arbitrary packets over the network. We can use SocksOverRDP to tunnel our custom packets and then proxy through it. We will use the tool as our proxy server.
We can start by downloading the appropriate binaries to our attack host to perform this attack. Having the binaries on our attack host will allow us to transfer them to each target where needed. We will need:
We can look for ProxifierPE.zip
We can then connect to the target using xfreerdp and copy the SocksOverRDPx64.zip file to the target. From the Windows target, we will then need to load the SocksOverRDP.dll using regsvr32.exe.
Now we can connect to 172.16.5.19 over RDP using mstsc.exe, and we should receive a prompt that the SocksOverRDP plugin is enabled, and it will listen on 127.0.0.1:1080
We will need to transfer SocksOverRDPx64.zip or just the SocksOverRDP-Server.exe to 172.16.5.19. We can then start SocksOverRDP-Server.exe with Admin privileges.
On our jump host we should have the proxy server:
After starting our listener, we can transfer Proxifier portable to the Windows 10 target (on the 10.129.x.x network), and configure it to forward all our packets to 127.0.0.1:1080. Proxifier will route traffic through the given host and port. See the clip below for a quick walkthrough of configuring Proxifier.
Also add to the proxification list the name of the executable that you want to proxify
With Proxifier configured and running, we can start mstsc.exe, and it will use Proxifier to pivot all our traffic via 127.0.0.1:1080, which will tunnel it over RDP to 172.16.5.19, which will then route it to 172.16.6.155 using SocksOverRDP-server.exe.
RDP Performance Considerations
When interacting with our RDP sessions on an engagement, we may find ourselves contending with slow performance in a given session, especially if we are managing multiple RDP sessions simultaneously. If this is the case, we can access the Experience tab in mstsc.exe and set Performance to Modem.
