VNC Security Type Enforcement Failure Remote Authentication Bypass

This script is Copyright (C) 2006-2017 Tenable Network Security, Inc.


Synopsis :

The remote VNC server is affected by multiple authentication bypass
vulnerabilities.

Description :

The version of VNC server running on the remote host is affected by
the following vulnerabilities :

- A flaw exists in RealVNC due to an error when handling
password authentication. A remote attacker can exploit
this to bypass authentication by using a specially
crafted request in which the client specifies an
insecure security type (e.g., 'Type 1 - None'), which is
accepted even if not offered by the server.
(CVE-2006-2369)

- A flaw exists in LibVNCServer within file auth.c due to
an error when handling password authentication. A remote
attacker can exploit this to bypass authentication by
using a specially crafted request in which the client
specifies an insecure security type (e.g., 'Type 1 -
None'), which is accepted even if not offered by the
server. (CVE-2006-2450)

See also :

http://www.nessus.org/u?ef2b8a64
http://www.nessus.org/u?8a2c16a0
http://www.nessus.org/u?b218067e
http://www.nessus.org/u?519d872d
https://github.com/LibVNC/libvncserver

Solution :

If using RealVNC, upgrade to RealVNC Free Edition 4.1.2 / Personal
Edition 4.2.3 / Enterprise Edition 4.2.3 or later.

If using LibVNCServer, upgrade to version 0.8.2 or later.

Risk factor :

High / CVSS Base Score : 7.5
(CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:P)
CVSS Temporal Score : 7.1
(CVSS2#E:F/RL:ND/RC:ND)
Public Exploit Available : true

Family: Misc.

Nessus Plugin ID: 21564 ()

Bugtraq ID: 17978
18977

CVE ID: CVE-2006-2369
CVE-2006-2450

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