CVE-2007-3656 in Firefox
Summary
by MITRE
Mozilla Firefox before 1.8.0.13 and 1.8.1.x before 1.8.1.5 does not perform a security zone check when processing a wyciwyg URI, which allows remote attackers to obtain sensitive information, poison the browser cache, and possibly enable further attack vectors via (1) HTTP 302 redirect controls, (2) XMLHttpRequest, or (3) view-source URIs.
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Analysis
by VulDB Data Team • 07/23/2019
The vulnerability described in CVE-2007-3656 represents a critical security flaw in Mozilla Firefox versions prior to 1.8.0.13 and 1.8.1.5, specifically targeting the browser's handling of wyciwyg URIs. This type of vulnerability falls under the category of improper access control as defined by CWE-284, where the application fails to properly enforce security zone boundaries that should normally restrict access to sensitive resources. The wyciwyg protocol, which stands for "what you see is what you get," is designed to allow browsers to display cached content from previous page loads, but Firefox's implementation failed to properly validate security contexts when processing these URIs.
The technical flaw manifests in Firefox's failure to perform essential security zone checks when processing wyciwyg URIs, creating a dangerous bypass mechanism that allows remote attackers to access information that should normally be restricted. This vulnerability specifically affects three attack vectors including HTTP 302 redirect controls, XMLHttpRequest functionality, and view-source URIs, all of which can be exploited to manipulate the browser's security model. The weakness enables attackers to craft malicious requests that can retrieve sensitive information from different security zones, effectively breaking down the isolation mechanisms that separate trusted and untrusted content within the browser environment.
The operational impact of this vulnerability is significant as it allows attackers to poison the browser cache with malicious content, potentially leading to persistent security issues across multiple browsing sessions. The ability to obtain sensitive information through wyciwyg URI processing creates opportunities for credential theft, session hijacking, and other advanced persistent threats. Furthermore, the vulnerability can enable additional attack vectors by allowing attackers to manipulate HTTP redirects and XMLHttpRequest operations, potentially leading to cross-site scripting attacks or other exploitation techniques. This vulnerability directly relates to ATT&CK technique T1190, which involves exploiting vulnerabilities in web browsers to gain unauthorized access to system resources.
The exploitation of this vulnerability demonstrates a fundamental flaw in Firefox's security architecture where the browser fails to properly enforce the same-origin policy and security zone boundaries that are essential for preventing information leakage between different trust levels. Attackers can leverage this weakness to bypass normal security controls that would typically prevent access to sensitive resources, effectively creating a backdoor into the browser's cache management system. The impact extends beyond simple information disclosure, as the ability to poison the browser cache creates persistent threats that can affect multiple users and sessions, making this vulnerability particularly dangerous in enterprise environments where browser security is paramount for protecting sensitive data.
Mitigation strategies for this vulnerability involve upgrading to Firefox versions 1.8.0.13 and 1.8.1.5 or later, which contain the necessary patches to properly implement security zone checks for wyciwyg URI processing. Organizations should also implement network-level controls to monitor and restrict access to potentially malicious wyciwyg URI patterns, while security teams should conduct thorough vulnerability assessments to identify any potential exploitation attempts. The fix implemented by Mozilla addresses the core issue by ensuring that wyciwyg URIs are properly validated against security zones before processing, preventing the unauthorized access that was previously possible through the flawed implementation. This vulnerability serves as a reminder of the importance of proper input validation and security boundary enforcement in web browser implementations, particularly when dealing with cached content and URI processing mechanisms that are critical to maintaining user security and privacy.