Affected Products: GNOME Vinagre and many other VNC viewers
Reproduction:
1. On your trusted desktop (e.g. Linux), open a text editor
2. Type "My password", select the text, and hit Ctrl-C
3. Open a Vinagre VNC connection to a remote host, e.g. running an
untrusted Windows
4. On the remote Windows host, open notepad.exe
5. In notepad's menu bar, using the mouse, click on Edit|Paste
Actual result:
notepad.exe shows "My password"
Expected result:
Nothing.
Impact:
Because I use a different password for every service, I have to
copy&paste them
(on my trusted desktop).
However, the remote machine is not trusted. In some cases, it's owned
by
a different company, in other cases I use VNC and a different machine
specifically because I don't trust the software and want it jailed.
If
the untrusted host can get to my passwords from my trusted desktop,
that's a critical security hole, because my passwords leak, and they
may
well give full access to other machines, my bank account or other
highly
sensitive data.
Affected users:
Using VNC is common usage pattern also used by government agencies
handling highly sensible documents (on the trusted host desktop
system)
while moving dangerous but necessary uses like Internet access,
Windows
system
and similar needs on physically different machines that are accessed
via
VNC.
The purpose is that the untrusted system has no way to get to the
information
on the trusted desktop, but that assumption is violated here.
Even normal users will be at risk. Many copy&paste passwords, or they
copy&paste snipplets of sensitive Word processing documents, e.g.
business plans.
Solution:
Given that most users are unaware of this risk, although the danger
may
nevertheless be very real for them, it is necessary for the default
configuration to be secure. They cannot be expected to actively
change
preferences or the software to protect themselves, because the
problem
isn't obvious in the first place.
Possible solutions:
1) a pref, with default off and a clear warning about this problem,
because many users will not be aware of it. A pref with default on or
without a clear warning is *not* sufficient.
2) Better yet: A button on the toolbar "Copy clipboard" Text is
copied
from host desktop clipboard to remote machine clipboard only when
that
button is pressed.
3) A combination of 1) and 2)
