USN-2365-1: LibVNCServer vulnerabilities

29 September 2014

libvncserver vulnerabilities

A security issue affects these releases of Ubuntu and its derivatives:

  • Ubuntu 14.04 LTS
  • Ubuntu 12.04 LTS

Summary

Several security issues were fixed in LibVNCServer.

Software Description

  • libvncserver - vnc server library

Details

Nicolas Ruff discovered that LibVNCServer incorrectly handled memory when being advertised large screen sizes by the server. If a user were tricked into connecting to a malicious server, an attacker could use this issue to cause a denial of service, or possibly execute arbitrary code. (CVE-2014-6051, CVE-2014-6052)

Nicolas Ruff discovered that LibVNCServer incorrectly handled large ClientCutText messages. A remote attacker could use this issue to cause a server to crash, resulting in a denial of service. (CVE-2014-6053)

Nicolas Ruff discovered that LibVNCServer incorrectly handled zero scaling factor values. A remote attacker could use this issue to cause a server to crash, resulting in a denial of service. (CVE-2014-6054)

Nicolas Ruff discovered that LibVNCServer incorrectly handled memory in the file transfer feature. A remote attacker could use this issue to cause a server to crash, resulting in a denial of service, or possibly execute arbitrary code. (CVE-2014-6055)

Update instructions

The problem can be corrected by updating your system to the following package versions:

Ubuntu 14.04 LTS
libvncserver0 - 0.9.9+dfsg-1ubuntu1.1
Ubuntu 12.04 LTS
libvncserver0 - 0.9.8.2-2ubuntu1.1

To update your system, please follow these instructions: https://wiki.ubuntu.com/Security/Upgrades.

In general, a standard system update will make all the necessary changes.

References