Mstsc en abyme

Published on 28 October 2010
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Perhaps the only thing Microsoft Terminal Services Client (mstsc, a.k.a, Remote Desktop Connection) has going for it is ubiquity. Since it installs with Windows, it's often the only remote access option available for a new machine; that is, until you log in and install something else. One thing it definitely does not have going for it is a feature set like, say, a menu.

I found myself stuck in a Droste effect with nested mstsc sessions today while installing OpenSSH on a new Windows 2003 server. Because this machine is in our DMZ, it takes two mstsc hops to get to it. In the process I needed to give the innermost session the Ctrl+Alt+Delete three finger salute. But how?  Unlike VNC, Radmin, and other remote control tools, there is no menu containing this option. I vaguely recalled some weird key combination to reach to the end of this mise en abyme, but could not get it right.

After a bit of googling and trial and error, I came up with this:

  • In the first session, open the Windows on screen keyboard. Oddly, this wasn't on the accessibility menu, so I had to run osk.exe directly.
  • Use osk to type Ctrl+Alt+End. This sends a Ctrl+Alt+Delete to the inner session.

Not at all difficult, just weird.