Check Point Advisories

TurboVNC Fence Message Stack-based Buffer Overflow (CVE-2019-15683)

Vulnerability
Protection

Check Point Reference:	CPAI-2019-1788
Date Published:	5 Mar 2020
Severity:	Critical
Last Updated:	Thursday 05 March, 2020
Source:
Industry Reference:	CVE-2019-15683
Protection Provided by:	Security Gateway R81, R80, R77, R75
Who is Vulnerable?	TurboVNC TurboVNC prior to 2.2.3
Vulnerability Description	A stack-based buffer overflow exists in TurboVNC server. The vulnerability is due to improper handling Fence message and lack of stack frame protection. A remote attacker can exploit this vulnerability by sending malicious packets to the Server. Successful exploitation of this vulnerability could result in arbitrary code execution under the security context of the Xvnc service.

Protection Overview

This protection detects attempts to exploit this vulnerability.

In order for the protection to be activated, update your Security Gateway product to the latest IPS update. For information on how to update IPS, go to SBP-2006-05, click on Protection tab and select the version of your choice.

Security Gateway R80 / R77 / R75

In the IPS tab, click Protections and find the TurboVNC Fence Message Stack-based Buffer Overflow (CVE-2019-15683) protection using the Search tool and Edit the protection's settings.
Install policy on all Security Gateways.

This protection's log will contain the following information:

Attack Name: Web Server Enforcement Violation.
Attack Information: TurboVNC Fence Message Stack-based Buffer Overflow (CVE-2019-15683)