CVE-2008-5503 in Firefox
Summary
by MITRE
The loadBindingDocument function in Mozilla Firefox 2.x before 2.0.0.19, Thunderbird 2.x before 2.0.0.19, and SeaMonkey 1.x before 1.1.14 does not perform any security checks related to the same-domain policy, which allows remote attackers to read or access data from other domains via crafted XBL bindings.
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Analysis
by VulDB Data Team • 08/03/2021
The vulnerability described in CVE-2008-5503 represents a critical security flaw in Mozilla Firefox 2.x versions prior to 2.0.0.19, Thunderbird 2.x versions prior to 2.0.0.19, and SeaMonkey 1.x versions prior to 1.1.14. This issue specifically affects the loadBindingDocument function within these applications, which is responsible for handling XML Binding Language (XBL) bindings that define user interface elements and their behaviors. The flaw stems from inadequate implementation of same-origin policy enforcement mechanisms that should prevent cross-domain data access attempts.
The technical nature of this vulnerability lies in the absence of proper security validation within the loadBindingDocument function. XBL bindings are XML documents that define how elements should behave and appear in web applications, and they can contain JavaScript code that executes within the context of the browser. When the loadBindingDocument function fails to verify that XBL bindings originate from the same domain as the requesting document, attackers can craft malicious XBL files that reference resources from other domains. This omission creates a pathway for cross-site scripting attacks and data exfiltration attempts, as the browser will execute these bindings without proper domain boundary checks.
The operational impact of this vulnerability is significant as it enables remote attackers to bypass fundamental web security restrictions that protect users from malicious content. Attackers can exploit this flaw by hosting malicious XBL files on a different domain and then referencing them from a compromised website. When a user visits the malicious site, the browser will load and execute the XBL bindings, potentially allowing access to sensitive data that should be restricted by the same-origin policy. This vulnerability specifically targets the security model that separates different domains to prevent unauthorized data access, effectively undermining the core principle of web browser security.
Security researchers have classified this vulnerability under CWE-284, which deals with improper access control, and it aligns with the ATT&CK technique T1059.007 for execution through scripting. The flaw demonstrates how insufficient input validation and security boundary enforcement can create exploitable conditions in browser applications. Organizations and users affected by this vulnerability should immediately update to the patched versions of their respective software, as the security patches implemented in versions 2.0.0.19 for Firefox, 2.0.0.19 for Thunderbird, and 1.1.14 for SeaMonkey include proper domain validation checks within the loadBindingDocument function. Additionally, network administrators should monitor for any suspicious XBL-related activity in their environments and consider implementing additional security measures such as content security policies to further protect against similar exploitation attempts.