Is passing a windows security token between processes permitted

Question

Imagine I have an existing process running under windows as a particular user. Would it be permitted for that process to take its current token (with something like OpenThreadToken and DuplicateTokenEx), pass it to another process on the same machine (perhaps through a network socket or some other IPC), and then expect that process to be able to use it to call CreateProcessAsUser?

From the documentation I have read (http://msdn.microsoft.com/en-us/library/ms682429%28VS.85%29.aspx), I've seen nothing which prohibits this but perhaps the token can only be used by the thread or process which created it.

(Why would you? I want to has a web request come to IIS, be authenticated, have IIS arrange the impersonation of the remote user and then pass the impersonation token to another server process (on the same machine) so that the server process can perform some security checks in the context of the remote user)

Answer 1

I haven't tried it, but it seems that this is the same question asked here. The description seems to make sense. Pass the process ID via whatever mechanism you choose (e.g., IPC), then call OpenProcess, OpenProcessToken, and finally ImpersonateLoggedOnUser. The resulting handle could be passed to CreateProcessAsUser. Well ... I know it could be passed to that function but whether it would have the desired result I do not know. Interesting question, though.

Answer 2

Why not just use named pipes, and then call ImpersonateNamedPipeUser() - it's safe and secure and easy! Note that the process doing the impersonation MUST have the Impersonation privilege.

Answer 3

Yes, that is possible. You can use DuplicateHandle to get a handle that is valid for the target process (send the new handle value to the target process, so it knows it.). However, the target process must still have the privileges to use the token accordingly. E.g. SE_IMPERSONATE to impersonate the user and SE_ASSIGN_PRIMARY to be used by CPAU. Of course there are some exceptions that you can read in MSDN for ImpersonateLoggedOnUser and CPAU.