Windows – How to kill a process by name for all users

Not knowing the password makes things complicated, but maybe the solution is: is it possible to temporarily blank out a user's password? (And afterwards reset it to whatever it was before.)

As a start:

First, get the login window to display. Just log out the current user, use fast user switching, or use SSH:

cd "/System/Library/CoreServices/Menu Extras/User.menu/Contents/Resources/"
sudo ./CGSession -suspend

Or, to switch to a specific user right away, which will probably show the login window (this suddenly no longer works on my 10.5 Leopard):

sudo ./CGSession -switchToUserID 501

What's shown now depends a bit on the System Preferences, but let's assume it's the users' icons and their names. To activate a name we'd have to type the first letters. Then, after Return, the password prompt shows. Alternatively one can select any name (like by pressing Arrow Down) and then press Option-Return to be prompted for both any username and its password. I don't know how one can tell which screen is shown, but let's save that for later...

So, to select the first (random) user name and press Option-Return, type a specific user name, hit Return, and type the password:

sudo osascript -e 'tell app "System Events"
  key code 125
  keystroke return using option down
  keystroke "the username"
  delay 1.0
  keystroke return
  delay 1.0
  keystroke "the password"
  delay 1.0
  keystroke return
end tell'

The above shows some error, which as far as I can tell does not limit the usage:

osascript[285] : 3891612: (connectAndCheck) Untrusted apps are not 
    allowed to connect to or launch Window Server before login.
_RegisterApplication(), FAILED TO establish the default connection to
    the WindowServer, _CGSDefaultConnection() is NULL.

Alternatively, use the language specific script from "Script the Login window through Apple Remote Desktop" (maybe one day the comments at that site will show a better solution):

tell process "SecurityAgent"
  set value of text field 1 of group 1 of window 1 to "the username"
  set value of text field 2 of group 1 of window 1 to "the password"
end tell
click button "Log In" of window 1 of application process "SecurityAgent"

But the main problem is: this still needs the password. However: obviously no password is needed when a user has a blank password. In fact, for blank passwords just clicking a user's icon is all that's needed. So, if sending keystrokes using AppleScript is acceptable, then maybe "all" that's left to figure out:

• Is it possible to temporarily blank out a user's password, to allow for starting (or resuming) the session without knowing that password...?

• Can one make the AppleScript error-proof? Like:

  • How to tell if the login window is visible? (maybe stat -f%Su /dev/console can help, as that yields root while the login window is displayed)
  • How to tell which login window is shown? (Like: one showing icons and login names, or a dropdown list, or maybe only a password prompt if someone selected to switch to some specific user?)
  • Get rid of the delays.
  • What about that error message?

(A note for testing: when using Screen Sharing it seems that setting the preference When controlling computers: Encrypt passwords and keystrokes only also retains the connection when the login window is shown, or after a user has successfully logged in. When using Encrypt all network data then my Mac needs to re-establish the Screen Sharing connection each time a login is shown or a user is switched.)

Processes usually get launched in a tree like fashion, I would advise launching Microsoft / Sysinternals Process Explorer, Start by clicking on the Show Process Tree (1) option, then find your process and right click and choose Kill Process Tree (2) This should kill both the original file and everything that it has launched.