Multiple heap-based buffer overflows in the ZRLE_DECODE function in common/rfb/zrleDecode.h in TigerVNC before 1.3.1, when NDEBUG is enabled, allow remote VNC servers to cause a denial of service (vncviewer crash) and possibly execute arbitrary code via vectors related to screen image rendering.

A heap-based buffer overflow was found in the way vncviewer rendered certain screen images from a vnc server. If a user could be tricked into connecting to a malicious vnc server, it may cause the vncviewer to crash, or could possibly execute arbitrary code with the permissions of the user running it.

The remote host is affected by the vulnerability described in GLSA-201411-03 (TigerVNC: User-assisted execution of arbitrary code)

    Two boundary errors in TigerVNC could lead to a heap-based buffer       overflow.
  Impact :

    A remote attacker could entice a user to connect to a malicious VNC       server using TigerVNC, possibly resulting in execution of arbitrary code       with the privileges of the process or a Denial of Service condition.
  Workaround :

    There is no known workaround at this time.

This update fixes CVE-2014-0011, a ZRLE decoding heap-based buffer overflow in vncviewer. This update contains some small fixes for issues that could cause the server or the viewer to crash, and includes a change that makes vncserver create clearer xstartup files.

Note that Tenable Network Security has extracted the preceding description block directly from the Fedora security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

According to its self-identified version number, the TigerVNC install hosted on the remote web server is affected by a heap-based buffer overflow vulnerability.

A flaw exists when performing bounds check during ZRLE decoding. This could allow a remote attacker with a malicious server and a specially crafted request to execute arbitrary code.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

This update fixes CVE-2014-0011, a ZRLE decoding heap-based buffer overflow in vncviewer.

Note that Tenable Network Security has extracted the preceding description block directly from the Fedora security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

ID	Name	Product	Family	Severity
85231	Amazon Linux AMI : tigervnc (ALAS-2015-576)	Nessus	Amazon Linux Local Security Checks	critical
78881	GLSA-201411-03 : TigerVNC: User-assisted execution of arbitrary code	Nessus	Gentoo Local Security Checks	critical
73352	Fedora 19 : tigervnc-1.3.0-10.fc19 (2014-4180)	Nessus	Fedora Local Security Checks	medium
73339	TigerVNC < 1.3.1 ZRLE Heap-based Buffer Overflow	Nessus	CGI abuses	medium
73170	Fedora 20 : tigervnc-1.3.0-14.fc20 (2014-4112)	Nessus	Fedora Local Security Checks	medium

Detections

Analytics

CVE-2014-0011

critical

Tenable Plugins

critical

critical

medium

medium

medium