CVE-2012-4873 in GNUBoard
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in the file_download function in GNUBoard before 4.34.21 allows remote attackers to inject arbitrary web script or HTML via the filename parameter.
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Analysis
by VulDB Data Team • 01/17/2025
The CVE-2012-4873 vulnerability represents a critical cross-site scripting flaw discovered in GNUBoard versions prior to 4.34.21, specifically within the file_download function. This vulnerability exposes web applications built on the GNUBoard platform to significant security risks by allowing remote attackers to execute malicious scripts through manipulated input parameters. The flaw resides in how the application processes the filename parameter, failing to properly sanitize or validate user-supplied data before incorporating it into web responses. This oversight creates an exploitable condition where attackers can craft malicious payloads that get executed in the context of other users' browsers when they access the affected download functionality.
The technical implementation of this vulnerability stems from insufficient input validation and output encoding practices within the GNUBoard codebase. When the file_download function processes the filename parameter, it directly incorporates user input into HTTP responses without adequate sanitization measures. This primitive handling of user data creates a classic XSS attack vector where malicious scripts can be injected through carefully crafted filenames. The vulnerability falls under CWE-79 which specifically addresses cross-site scripting flaws, and aligns with ATT&CK technique T1566.001 for initial access through malicious file downloads. Attackers can leverage this weakness by uploading or referencing files with malicious script content in their names, which then gets executed when legitimate users attempt to download these files.
The operational impact of CVE-2012-4873 extends beyond simple script execution, potentially enabling attackers to perform session hijacking, deface websites, steal sensitive user information, or redirect victims to malicious sites. When exploited, this vulnerability can compromise the integrity of the entire GNUBoard installation, allowing attackers to manipulate content, access user credentials, or establish persistent access to the affected systems. The vulnerability affects any web application using GNUBoard versions before 4.34.21, particularly those with file download capabilities that do not properly validate user input. Organizations running affected systems face potential data breaches, reputational damage, and regulatory compliance violations, as this vulnerability can be exploited to gain unauthorized access to sensitive information stored within the GNUBoard environment.
Mitigation strategies for CVE-2012-4873 primarily focus on implementing proper input validation and output encoding mechanisms. The most effective solution involves upgrading to GNUBoard version 4.34.21 or later, which includes patched code that properly sanitizes the filename parameter before processing. Additionally, administrators should implement proper input validation by filtering special characters from user-supplied filenames and employing output encoding techniques to prevent script execution in web contexts. Security measures should include implementing content security policies, using web application firewalls to detect and block malicious requests, and conducting regular security audits of input handling functions. The vulnerability also highlights the importance of following secure coding practices as outlined in OWASP top ten recommendations, particularly regarding input validation and output encoding. Organizations should also consider implementing automated patch management systems to ensure timely deployment of security updates and maintain comprehensive monitoring of their web applications for similar vulnerabilities.