Re: [opensuse] XVNC Activating itself -- sign of scurity breach?

On Wed, May 30, 2007 at 10:00:35PM -0400, Patrick Shanahan wrote:
* David McMillan <skyefire@xxxxxxxxxxxx> [05-30-07 21:36]:
Patrick Shanahan wrote:
* David McMillan <skyefire@xxxxxxxxxxxx> [05-30-07 20:56]:
In the past two months, I've had two incidents where, when I ran 'top,'
I found XVNC running (and taking up a good 75% of my CPU), for no
apparent reason on my 10.2 system.
Now, I have "Remote Desktop Sharing" turned on on this machine (though
I've never been able to get VNC to connect across the LAN from my WXP
laptop -- only browsing to http://host:5801 works so far), but at
neither of these incidents had I been using, or even attempting to use,
a VNC or RD connection to the 10.2 machine, at any time in the recent
past.

You *are* using vnc, http://host:5801 is a vnc connection.

Yes, I know -- what I meant was, *at the time of the incidents,* I
hadn't made any VNC connection attempts, via HTTP or otherwise, in
*days,* if not weeks. There were definitely no VNC connections being
made from any of *my* machines on my LAN. That's what's puzzling (and
worrying me) about seeing XVNC active, and eating up so much CPU.

My guess...

Xvnc is the VNC server process. It has to be running for you to be able to
connect on http://host:5801 (unless you use some inetd magic to get it to
auto-start). Basically, you have Xvnc running ready to accept connections
on http://host:5801.

Why is it using so much CPU? I'd guess that you've got a screensaver
configured. The screensaver program isn't intelligent enough to realise
that it's a VNC session and therefore doesn't need a screensaver, so it
detects that there has been no keyboard or mouse activity for a while
(unsurprising, since there are no connected clients), and starts running
the screensaver. The Xvnc process has to respond to the screensaver
program's commands to draw things on its X desktop, and this is what is
taking all the CPU.

It could be other things, but this is my best guess.

--
David Smith Work Email: Dave.Smith@xxxxxx
STMicroelectronics Home Email: David.Smith@xxxxxxxxxxxxxxxxxxxx
Bristol, England GPG Key: 0xF13192F2
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