CVE-2008-2808 in Firefox
Summary
by MITRE
Mozilla Firefox before 2.0.0.15 and SeaMonkey before 1.1.10 do not properly escape HTML in file:// URLs in directory listings, which allows remote attackers to conduct cross-site scripting (XSS) attacks or have unspecified other impact via a crafted filename.
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Analysis
by VulDB Data Team • 03/16/2021
The vulnerability identified as CVE-2008-2808 represents a critical cross-site scripting weakness in Mozilla Firefox versions prior to 2.0.0.15 and SeaMonkey versions prior to 1.1.10. This flaw specifically manifests in the handling of file:// URLs within directory listings, where the browsers fail to adequately sanitize HTML characters present in filenames. The issue stems from insufficient input validation and output encoding mechanisms that should prevent malicious content from being interpreted as executable code when directory listings are displayed. The vulnerability operates at the application layer and affects the browser's security model by allowing attackers to inject malicious scripts through file names that contain HTML or JavaScript code.
The technical implementation of this vulnerability exploits the browser's directory listing functionality where file names are rendered directly without proper HTML escaping. When a user navigates to a directory containing files with specially crafted names that include HTML tags or JavaScript code, the browser displays these filenames in the directory listing without proper sanitization. This creates an environment where attackers can place malicious content within file names that gets executed when the directory listing is rendered, effectively bypassing the same-origin policy that normally protects against such attacks. The vulnerability falls under CWE-79 which specifically addresses Cross-Site Scripting flaws, and demonstrates the importance of proper input validation and output encoding in web applications. The flaw can be categorized under the ATT&CK technique T1059.007 for Scripting, as it allows for the execution of malicious scripts through file name manipulation.
The operational impact of this vulnerability extends beyond simple XSS attacks, as it can enable attackers to perform a wide range of malicious activities including session hijacking, credential theft, and redirection to malicious websites. When a user visits a directory containing maliciously crafted filenames, the injected scripts can execute in the context of the victim's browser session, potentially leading to complete compromise of the user's browsing environment. The vulnerability is particularly dangerous because it can be exploited through legitimate directory browsing functionality, making it difficult to detect and prevent through conventional security measures. Attackers can leverage this weakness to create malicious file names that, when displayed in directory listings, execute arbitrary code or steal sensitive information from users who browse to affected directories. The unspecified other impacts mentioned in the original description suggest that this vulnerability could potentially enable more severe attacks beyond traditional XSS scenarios.
Mitigation strategies for CVE-2008-2808 primarily focus on updating affected browser versions to the patched releases that properly escape HTML characters in directory listings. Organizations should immediately deploy security updates for Firefox 2.0.0.15 and SeaMonkey 1.1.10 to address this vulnerability. Additionally, administrators should implement network-level protections such as web application firewalls that can detect and block malicious file name patterns, and establish security policies that limit access to potentially dangerous file systems. Browser security hardening measures including disabling directory browsing capabilities where possible and implementing strict content security policies can further reduce the attack surface. The vulnerability highlights the critical importance of proper HTML escaping and input validation in web applications, and serves as a reminder that even seemingly benign functionality like directory listing can present security risks when not properly secured. Organizations should also consider implementing automated vulnerability scanning tools that can detect and alert on potentially malicious file names in web environments.