Full Disclosure mailing list archives

Re: Re: RealVNC/WinVNC Multiple vulnerabilities


From: Simon Roberts <thorpflyer () yahoo com>
Date: Tue, 21 Jun 2005 09:07:36 -0700 (PDT)

Can't say I agree that a VNC server implementation should simply refuse
to run in such a mode. There are plenty of situations where you being
able to get to my server implies that I've already suffered a massive
security breach anyway. Under those conditions, I think the "balance"
approach applies: let me use no authentication and maybe I'll use a
half-decent password, or put up with a "real" protection mechanism,
where it really matters. Like how I get in through my firewall, instead
of how I mess around inside it.

Even if this binary is fixed so no-auth isn't possible, if you're
letting your users configure this rather than giving it to them in a
centrally controlled fashion, then perhaps you already have worse
problems, like they can probably install their own software, etc...

Anyway, I guess my point is that it's my humble opinion that you don't
have the right to mandate the security vs. convenience balance for
everyone else.

Just $0.02, obviously,
Cheers,
Simon


--- class <ad () class101 org> wrote:

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Hash: SHA1
 
Of course, if you think you know of any viable attacks on VNC
servers then feel free to get in touch.

sure I have mailed you a nice list of ip:5900 shomydeskt0p :) funny
no
? good lines ? ;)

The output that you've included just seems to show that (assuming
"passworded" means "was able to guess password") your VNC Servers
have been configured with poorly chosen passwords.

passworded mean its passworded , nothing much, my scan doesnt include
any password brteforce, but it show you how easy it is to scan for
your app with "No authentications", who is enough crazy thos days to
add such options ? so easy hacking :)


The output that you've included just seems to show that (assuming
"passworded" means "was able to guess password") your VNC
Servers have been configured with poorly chosen passwords.





-----Original Message----- From: vnc-list-admin () realvnc com
[mailto:vnc-list-admin () realvnc com] On Behalf Of
class101 () phreaker net Sent: 19 June 2005 15:35 To:
vnc-list () realvnc com Cc: Full-Disclosure Subject:
RealVNC/WinVNC Multiple vulnerabilities


Two simple vulnerabilities wich may lead to an os guess + null
session + several others infos while scanning port 5900, low risk
on paper but high online risk:

My 2cent suggestion to the realvnc team would be to totally
remove this "No Authentication" option wich wasnt present in the
oldold winvnc, and to standardize what is answering all your
servers to restrict the private informations guessing.


quick screenshot( of a simple dfind scanning test on a range that
I thought really secured :>):

***.7.41:5900 realvnc4 ssl encryption ***.16.83:5900 realvnc4
passworded (free ed. win32) ***.16.91:5900 realvnc4 passworded
(free ed. win32) ***.16.113:5900 realvnc4 passworded (free ed.
win32) ***.16.163:5900 realvnc4 passworded (free ed.
x86/SPARC/HPUX) ***.16.180:5900 realvnc4 passworded (free ed.
x86/SPARC/HPUX) ***.16.202:5900 RealVNC4 NULL Session (free ed.
x86/SPARC/HPUX) ***.16.237:5900 realvnc4 passworded (free ed.
x86/SPARC/HPUX) ***.22.217:5900 realvnc4 passworded (free ed.
x86/SPARC/HPUX) ***.29.91:5900 realvnc4 passworded (free ed.
x86/SPARC/HPUX) ***.29.92:5900 RealVNC4 NULL Session
(perso/enterp ed. win32 encryption:OFF) ***.29.93:5900 realvnc4
passworded (free ed. x86/SPARC/HPUX) ***.29.157:5900 realvnc4
passworded (perso/enterp ed. win32 encryption:OFF)
***.29.201:5900 realvnc4 passworded (free ed. x86/SPARC/HPUX)
***.29.234:5900 realvnc4 passworded (free ed. win32)
***.35.45:5900 realvnc4 passworded (perso/enterp ed. win32
encryption:ON) ***.40.192:5900 RealVNC4 NULL Session
(perso/enterp ed. win32 encryption:ON)

If you are seeking for more informations and you are from
@realvnc.com, email me, or else look at class101.org and
hat-squad.com

_______________________________________________ VNC-List mailing
list VNC-List () realvnc com To remove yourself from the list visit:
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