Check Point Advisories

Mozilla Products IDN Spoofing (CVE-2005-0233)

Vulnerability
Protection

Check Point Reference:	CPAI-2005-194
Date Published:	25 Oct 2009
Severity:	High
Last Updated:	Monday 14 July, 2014
Source:
Industry Reference:	CVE-2005-0233
Protection Provided by:	Security Gateway R81, R80, R77, R75
Who is Vulnerable?
Vulnerability Description	The Internationalized Domain Names (IDN) standard defines specifications for the representation of domain names containing non-ASCII characters. The IDN standard has been developed to allow representation of Unicode domain names without depending on alterations to any network infrastructure components such as DNS. The specification uses ASCII characters to represent encoded Unicode characters found in the domain name. An IDN converted name begins with a special prefix "xn--" followed by the encoded domain name. The IDN support in Mozilla products allows remote attackers to spoof domain names using punycode encoded domain names. Punycode (RFC 3492) is a syntax to uniquely encode Unicode strings as an ASCII string, specifically the subset of ASCII characters allowed in host names (letters, digits and hyphens). These punycode encoded domains can be crafted to resemble trusted domains using homograph characters from other character sets. These crafted domains can be used in URLs or SSL certificates to facilitate phishing attacks. The target application will not exhibit any unusual behaviour during an attack. As a result of a successful attack, the target user may be mislead to the source of the content that is being rendered by the affected Mozilla product.

Protection Overview

This protection will detect and block attempts to exploit this vulnerability, by blocking attempts to connect to a URL suspected of IDN spoofing.Note that the actual misleading of the client will have been in a previous connection.

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 Mozilla Products IDN Spoofing 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 Client Enforcement Violation.
Attack Information: Mozilla products IDN spoofing