So, if I ssh into a system and have X-forwarding for the session, anything
including my initial [bash or other] shell could be logging my local
keystrokes, even in other windows?  (assuming the shell binay was modified
to log such events)
They can only get X events, though, so they don't get keystrokes that go
to a non-X session like one of the text terminals -- is that correct?

If this is true, I think we'll all be more wary of logging in to others'
systems... I'm also curious about what signals are remotely visible when the
local X system, being ssh'ed *from*, is a cygwin/X system.  Furthermore,
what about a cygwin/X running inside wine or xmware?  Is the sniffing
potential limited to cygwin's X session, or would it inherit access through
the hosting OS's desktop (in the caee of cygwin on wine or vmware)?

ever-so-curious,

   Ben


On Thu, 29 Jan 2004 22:02:06 -0800
Bob Miller <[EMAIL PROTECTED]> wrote:

| Ben Barrett wrote:
| 
| > 1. I never realized that 'xkill' could pass the appropriate signals
| > through a remote Xwindows connection, which in my case was
| > SSH-tunnelled.  If anyone has explored this or knows more, I'm very
| > curious, about the security implications, for instance; what can you
| > tell me?   Example:  you log your buddy into their remote account as
| > they borrow your system momentarily, they do their stuff, but could
| > easily (accidentally or otherwise) kill anything on your desktop, or
| > possibly the entire session(?).  I know they could close anything,
| > having physical access, but I feel like I'm not getting the whole
| > picture.
| 
| X is a network-transparent window system.  That means that it doesn't
| matter whether there is a network between the client and the server.
| The client has exactly the same privileges and capabilities in either
| case.  There is at least one exception in the X11 protocol, the one
| that I can remember is that the "xhost" command only works through a
| local connection.  But you can do nearly everything remotely that you
| can do locally.  Linux Terminal Servers rely on that.
| 
| Some of the things a client (any client) can do include: reading any
| part of the screen or offscreen pixmaps, reading or changing any
| window's properties, and reading events from the mouse and keyboard
| (e.g., keystroke logging).
| 
| I'm sure you can see what the security implications are -- if you're
| going to run an X client on a host, your workstation, and other hosts
| that also run X clients on it, are no more secure than that host.
| 

(thanks Bob!!)
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