Follow @Openwall on Twitter for new release announcements and other news
[<prev] [next>] [day] [month] [year] [list]
Date: Thu, 25 Sep 2014 13:59:51 +0200
From: Andrea Barisani <>
Subject: [oCERT-2014-007] libvncserver multiple issues

#2014-007 libvncserver multiple issues


Virtual Network Computing (VNC) is a graphical sharing system based on the
Remote Frame Buffer (RFB) protocol.

The LibVNCServer project, an open source library for implementing VNC
compliant communication, suffers from a number of bugs that can be potentially
exploited with security impact.

Various implementation issues resulting in remote code execution and/or DoS
conditions on both the VNC server and client side have been discovered.

 1. A malicious VNC server can trigger incorrect memory management
    handling by advertising a large screen size parameter to the VNC
    client. This would result in multiple memory corruptions and could
    allow remote code execution on the VNC client.

 2. A malicious VNC client can trigger multiple DoS conditions on the VNC
    server by advertising a large screen size, ClientCutText message
    length and/or a zero scaling factor parameter.

 3. A malicious VNC client can trigger multiple stack-based buffer
    overflows by passing a long file and directory names and/or attributes
    (FileTime) when using the file transfer message feature.

It should be noted that every described issue represents a post-authentication
bug, therefore the server side conditions can be anonymously leveraged only if
the VNC server is configured to allow unauthenticated sessions.

Affected version:

LibVNCServer <= 0.9.9

Fixed version:

LibVNCServer, N/A

Credit: vulnerability report received from Nicolas Ruff
        of Google Security Team <nruff AT>.

CVE: CVE-2014-6051 (1), CVE-2014-6052 (1), CVE-2014-6053 (2),
     CVE-2014-6054 (2), CVE-2014-6055 (3)


2014-09-05: vulnerability report received
2014-09-16: contacted affected vendors
2014-09-22: contacted additional affected vendors
2014-09-25: advisory release



Andrea Barisani |                Founder & Project Coordinator
          oCERT | OSS Computer Security Incident Response Team

 0x864C9B9E 0A76 074A 02CD E989 CE7F AC3F DA47 578E 864C 9B9E
        "Pluralitas non est ponenda sine necessitate"

Powered by blists - more mailing lists

Please check out the Open Source Software Security Wiki, which is counterpart to this mailing list.

Confused about mailing lists and their use? Read about mailing lists on Wikipedia and check out these guidelines on proper formatting of your messages.