title: How does Bitvise SSH Server authenticate user without a password?
body: <p>Since version 5.50 the Bitvise SSH Server allows connected client to authenticate to Windows user account without providing this user's Windows password. See here: <a href="https://www.bitvise.com/ssh-server-version-history" rel="nofollow">https://www.bitvise.com/ssh-server-version-history</a></p>
  
  <p>I've checked it myself - it does indeed.</p>
  
  <p>My question is of pure curiosity: what kind of sorcery is this? Is there any WinAPI that allows such thing or is this some kind of clever hack? I always thought it is impossible to impersonate as other user without a password (as even when configuring Windows service or scheduled task to "run as user" it is neccessary to provide one).</p>