CVE-2004-2227 in Firefox
Summary
by MITRE
Mozilla Firefox before 1.0 truncates long filenames in the file download dialog box, which makes it easier for remote attackers to trick users into downloading files with dangerous extensions.
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Analysis
by VulDB Data Team • 03/10/2021
The vulnerability described in CVE-2004-2227 represents a significant security flaw in Mozilla Firefox versions prior to 1.0 that affects the file download dialog interface. This issue stems from the browser's handling of filename display in its download confirmation dialog, where long filenames are truncated to fit within the available display space. The truncation mechanism, while seemingly benign from a user interface perspective, creates a critical security risk that can be exploited by malicious actors to deceive users during the download process. The vulnerability specifically impacts the user's ability to properly identify file extensions, which are crucial indicators of file type and potential malicious intent. This flaw aligns with CWE-128, which addresses issues related to truncation of filenames or paths, and represents a classic case of inadequate input validation in user-facing interfaces.
The technical implementation of this vulnerability occurs when Firefox processes file downloads and displays the filename in the download dialog box. When a filename exceeds the display capacity of the dialog window, the browser automatically truncates the text, typically showing only the beginning portion of the filename while hiding the file extension. This truncation behavior creates a scenario where users may see a filename that appears legitimate or harmless while the actual file extension remains hidden from view. Attackers can exploit this by crafting malicious filenames that appear benign in the truncated display but contain dangerous extensions such as .exe, .bat, .scr, or other executable formats that could compromise system security when executed by unsuspecting users.
The operational impact of this vulnerability extends beyond simple user deception and represents a serious threat to system security and user awareness. Users operating with vulnerable Firefox versions face increased risk of inadvertently downloading and executing malicious files that would otherwise be clearly identifiable through their extensions. The attack surface is particularly concerning because it leverages social engineering principles combined with technical flaws, making it more difficult for users to detect malicious intent. This vulnerability can be exploited in various contexts including phishing attacks, drive-by downloads, and malicious website campaigns where attackers create file names that appear to be legitimate documents or media files while actually containing executable code. The risk is amplified because users typically rely on file extensions as their primary indicator of file type and potential threat level.
Mitigation strategies for CVE-2004-2227 should focus on both immediate remediation and long-term security improvements. The primary and most effective solution involves upgrading to Mozilla Firefox 1.0 or later versions where the filename truncation issue has been resolved through improved dialog display mechanisms. Organizations should implement comprehensive patch management policies to ensure all users have access to secure browser versions. Additionally, security awareness training should emphasize the importance of verifying file extensions even when they appear truncated, and users should be encouraged to pay attention to the complete file paths and download locations rather than relying solely on the displayed filename. System administrators should consider implementing additional security layers such as content filtering, application whitelisting, and endpoint protection solutions to provide defense-in-depth against potential exploitation attempts. The vulnerability also highlights the importance of proper input validation and user interface design in security-critical applications, aligning with ATT&CK technique T1059 which addresses execution through various file types and system interfaces.