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Update Protection against Microsoft Internet Explorer findText Unicode Parsing Denial of Service Vulnerability

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Check Point Reference: CPAI-2011-005
Date Published:
Severity:
Source: SecurityFocus Bugtraq ID: 35799
Industry Reference(s): CVE-2009-2655
Protection Provided by: Security Gateway
  • R75
  • R71
  • R70
VPN-1
  • NGX R65
VSX
  • NGX R65
Who is Vulnerable?
Microsoft Internet Explorer 8 on Windows XP SP3
Microsoft Internet Explorer 7 on Windows XP SP3 
Vulnerability Description
A denial of service vulnerability has been reported in the way Microsoft Internet Explorer parses HTML pages. A remote attacker could exploit this issue by convincing a user to visit a specially crafted HTML document or open a malicious Web page. Successful exploitation could result in a denial of service condition, thus crashing the vulnerable browser.
Vulnerability Details
The vulnerability is due to an error in the mshtml.dll library. A remote attacker might exploit this issue by persuading a user to visit a specially crafted Web page that calls the JavaScript findText method with a crafted Unicode string in the first argument and only one additional argument. Successful exploitation of this vulnerability would create a denial of service condition, causing the browser to crash. 

Protection Overview
This protection will detect and block attempts to exploit this vulnerability via malicious HTML pages.

In order for the protection to be activated, update your Security Gateway/VPN-1 product to the latest IPS/SmartDefense update. For information on how to update IPS/SmartDefense,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 > Web Intelligence > HTTP Client Protections > Microsoft Internet Explorer Vulnerabilities.
2. In the right pane, double-click the Internet Explorer findText Unicode Parsing Denial of Service 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: Web Client Enforcement Violation
Attack Information: Internet Explorer findText Unicode parsing denial of service

Security Gateway: R70/R71

How Can I Protect My Network?
1. In the IPS tab, click Protections > By Protocol > Web Intelligence > HTTP Client Protections > Microsoft Internet Explorer Vulnerabilities.
2. In the right pane, double-click the Internet Explorer findText Unicode Parsing Denial of Service 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: Web Client Enforcement Violation
Attack Information: Internet Explorer findText Unicode parsing denial of service

VPN-1 NGX R65 & VSX NGX R65

How Can I Protect My Network?
1. In the SmartDefense tab, click Web Intelligence > HTTP Client Protections > Microsoft Internet Explorer Vulnerabilities > Internet Explorer findText Unicode Parsing Denial of Service.
2. In the configuration pane, under Settings > Mode, check Active.
3. Install policy on all modules.

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

Attack Name: Web Client Enforcement Violation
Attack Information: Internet Explorer findText Unicode parsing denial of service