Check Point Advisories

JavaScript Percent-Encoding Obfuscation

Vulnerability
Protection

Check Point Reference:	SBP-2009-17
Date Published:	23 Oct 2014
Severity:	Medium
Last Updated:	Thursday 23 October, 2014
Source:
Protection Provided by:	Security Gateway R81, R80, R77, R75, R71, R70
Who is Vulnerable?
Vulnerability Description	Although various security products provide coverage against many web vulnerabilities, such as ActiveX exploits, these known exploits could potentially bypass security products by using JavaScript obfuscation techniques.An example of such a technique is percent-encoding, also known as URL encoding, which is a mechanism for encoding information in a Uniform Resource Identifier (URI). Such techniques obfuscate known exploits so they will bypass security rules - since the exploits are being thoroughly obfuscated, IDS and IPS systems will not recognize them and thus will allow them to pass without any notification.

Protection Overview

This protection triggers when the code contains malicious percent-encoding, such as deliberate unicode encoding.

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 / R71 / R70

In the IPS tab, click Protections and find the JavaScript Percent-Encoding Obfuscation 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: Security Products Enforcement Violation.
Attack Information: JavaScript percent-encoding obfuscation