CVE-2012-4195 in Firefox
Summary
by MITRE
The nsLocation::CheckURL function in Mozilla Firefox before 16.0.2, Firefox ESR 10.x before 10.0.10, Thunderbird before 16.0.2, Thunderbird ESR 10.x before 10.0.10, and SeaMonkey before 2.13.2 does not properly determine the calling document and principal in its return value, which makes it easier for remote attackers to conduct cross-site scripting (XSS) attacks via a crafted web site, and makes it easier for remote attackers to execute arbitrary JavaScript code by leveraging certain add-on behavior.
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Analysis
by VulDB Data Team • 10/22/2024
The vulnerability identified as CVE-2012-4195 resides within the nsLocation::CheckURL function of Mozilla Firefox and related applications including Thunderbird and SeaMonkey. This flaw represents a critical security weakness that undermines the browser's ability to properly validate and enforce security boundaries when processing URLs and cross-origin requests. The vulnerability specifically affects versions prior to Firefox 16.0.2, Firefox ESR 10.x before 10.0.10, Thunderbird 16.0.2, Thunderbird ESR 10.x before 10.0.10, and SeaMonkey 2.13.2, creating a window of exposure for users running these older versions.
The technical flaw stems from improper handling of document and principal determination within the nsLocation::CheckURL function. When a web page attempts to access or manipulate URL locations, the function should validate whether the requesting document has appropriate permissions and whether the operation adheres to the same-origin policy. However, due to this vulnerability, the function fails to correctly identify the calling document's security context and principal, leading to a bypass of critical security checks. This misconfiguration allows malicious actors to craft web pages that can exploit the function's weakness to perform unauthorized operations across different security domains.
The operational impact of this vulnerability is severe and multifaceted, enabling attackers to execute cross-site scripting attacks with significantly reduced complexity. The flaw creates a pathway for remote attackers to inject malicious JavaScript code into vulnerable applications, potentially leading to complete session hijacking, data theft, or arbitrary code execution on affected systems. The vulnerability's exploitation becomes even more dangerous when combined with certain add-on behaviors, as the compromised security context can be leveraged to extend the attack surface beyond the initial breach point. This weakness directly aligns with CWE-79, which describes cross-site scripting vulnerabilities, and represents a classic example of insufficient input validation and improper access control mechanisms.
From an attack perspective, this vulnerability maps to multiple ATT&CK techniques including T1059.007 for JavaScript execution and T1211 for exploitation of vulnerable applications. The attack vector typically involves hosting malicious content on a compromised website that triggers the vulnerable function when a user visits the page. The exploit can be particularly insidious because it requires minimal user interaction beyond visiting the malicious site, and the attack can be amplified through various browser add-ons that may inadvertently expose additional attack surfaces. Organizations and users running affected versions face heightened risk of successful exploitation, particularly in environments where users may encounter untrusted web content or where browser add-ons are frequently used. The vulnerability demonstrates how seemingly minor flaws in core browser functionality can create significant security risks that affect multiple applications within the same ecosystem.