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Update Protection against UltraVNC VNCLog Buffer Overflow

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Check Point Reference: CPAI-2006-208
Date Published:
Severity:
Last Updated:
Source: Secunia Advisory: SA19513
Industry Reference(s): CVE-2006-1652
Protection Provided by: Security Gateway
  • R75
Who is Vulnerable?
UltraVNC Project UltraVNC 1.0.1 and below
Vulnerability Description
UltraVNC is an open source client/server remote control application which uses the Virtual Network Computing (VNC) protocol. The VNC protocol allows a user to control a remote host by sending mouse and keyboard events, and receiving screen and sound updates. UltraVNC offers several extra features and control options, such as an optimized video driver, multiple monitor support, and so on.
Vulnerability Details
There exists a buffer overflow vulnerability in the UltraVNC server. The vulnerability is caused by improper validation of user supplied requests sent to the affected component. A successful attack can result in the termination of the UltraVNC service.
In a situation where the malicious user is successful in injecting and executing supplied code, the behaviour of the target system is dependent on the nature the injected code. Any code injected into the vulnerable component would execute in the security context of the user that launched the UltraVNC server application, though it may be SYSTEM, as the application has the option of running as a service. If the case of unsuccessful code injection, the UltraVNC application will terminate, causing denial of service.

Protection Overview
This protection will detect and block 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, Protection tab and select the version of your choice.

To configure the defense, select your product from the list below and follow the related protection steps.

Security Gateway R75

How Can I Protect My Network?
1. In the IPS tab, click Protections > By Protocol > IPS Software Blade > Application Intelligence > Remote Control Applications.
2. In the right pane, double-click the UltraVNC VNCLog Buffer Overflow protection.
3. In the Protection Details window, click on Edit. Choose the protection's Action (Override IPS Policy with: Prevent/Detect), and apply Additional Settings.
4. Install policy on all modules.

How Do I Know if My Network is Under Attack?
SmartView Tracker will log the following entries:

Attack Name: RDP Enforcement Violation
Attack Information: UltraVNC VNCLog buffer overflow