Debian Security Advisory

DLA-1617-1 libvncserver -- LTS security update

Date Reported:
27 Dec 2018
Affected Packages:
libvncserver
Vulnerable:
Yes
Security database references:
In the Debian bugtracking system: Bug 916941.
In Mitre's CVE dictionary: CVE-2018-6307, CVE-2018-15127, CVE-2018-20019, CVE-2018-20020, CVE-2018-20021, CVE-2018-20022, CVE-2018-20023, CVE-2018-20024.
More information:

Kaspersky Lab discovered several vulnerabilities in libvncserver, a C library to implement VNC server/client functionalities.

  • CVE-2018-6307

    a heap use-after-free vulnerability in the server code of the file transfer extension, which can result in remote code execution. This attack appears to be exploitable via network connectivity.

  • CVE-2018-15127

    contains a heap out-of-bound write vulnerability in the server code of the file transfer extension, which can result in remote code execution. This attack appears to be exploitable via network connectivity.

  • CVE-2018-20019

    multiple heap out-of-bound write vulnerabilities in VNC client code, which can result in remote code execution.

  • CVE-2018-20020

    heap out-of-bound write vulnerability in a structure in VNC client code, which can result in remote code execution.

  • CVE-2018-20021

    CWE-835: Infinite Loop vulnerability in VNC client code. The vulnerability could allow an attacker to consume an excessive amount of resources, such as CPU and RAM.

  • CVE-2018-20022

    CWE-665: Improper Initialization weaknesses in VNC client code, which could allow an attacker to read stack memory and can be abused for information disclosure. Combined with another vulnerability, it can be used to leak stack memory layout and bypass ASLR.

  • CVE-2018-20023

    Improper Initialization vulnerability in VNC Repeater client code, which could allow an attacker to read stack memory and can be abused for information disclosure. Combined with another vulnerability, it can be used to leak stack memory layout and bypass ASLR.

  • CVE-2018-20024

    a null pointer dereference in VNC client code, which can result in DoS.

For Debian 8 Jessie, these problems have been fixed in version 0.9.9+dfsg2-6.1+deb8u4.

We recommend that you upgrade your libvncserver packages.

Further information about Debian LTS security advisories, how to apply these updates to your system and frequently asked questions can be found at: https://wiki.debian.org/LTS