CVE-2008-1036

Vulnerability

The International Components for Unicode (ICU) library in Apple Mac OS X before 10.5.3, Red Hat Enterprise Linux 5, and other operating systems omits some invalid character sequences during conversion of certain character encodings. This flaw can allow specially crafted invalid data to bypass content filters, leading to cross-site scripting (XSS) attacks. Affected versions include ICU libraries on Mac OS X < 10.5.3, Red Hat Enterprise Linux 5, and Ubuntu systems before libicu update USN-747-1. [1][2]

Exploitation

An attacker can exploit this vulnerability by crafting input data that contains invalid character sequences which ICU will silently drop during conversion. If a user or automated system processes this specially crafted data through an application linked against the ICU library (such as a web browser or content filter), the omitted sequences can allow attacker-controlled content to bypass security filters. No authentication or elevated privileges are required; the attack can be triggered remotely by tricking a user into visiting a malicious page or processing a crafted file. [2]

Impact

Successful exploitation enables cross-site scripting (XSS) attacks, allowing an attacker to inject arbitrary script or HTML into a victim's browser session. This can lead to theft of cookies, session tokens, or other sensitive information, and potentially allow the attacker to perform actions on behalf of the victim within the affected site's security context. [1][2]

Mitigation

Apple addressed this vulnerability in Mac OS X 10.5.3. Red Hat released an update via RHSA-2009-0296 for Red Hat Enterprise Linux 5. Ubuntu published an update in USN-747-1 for ICU packages. Users should apply relevant vendor patches as soon as possible. If patching is not possible, consider using input validation and output encoding to mitigate XSS risks, and restrict processing of untrusted data by ICU-linked applications. [1][2]