CVE-2018-15581 in GNUBOARD5
Summary
by MITRE
Cross-Site Scripting (XSS) vulnerability in adm/faqmasterformupdate.php in gnuboard5 before 5.3.1.6 allows remote attackers to inject arbitrary web script or HTML.
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Analysis
by VulDB Data Team • 09/19/2024
The vulnerability identified as CVE-2018-15581 represents a critical cross-site scripting flaw discovered in the gnuboard5 content management system prior to version 5.3.1.6. This vulnerability specifically affects the adm/faqmasterformupdate.php administrative component, which serves as a critical interface for managing frequently asked questions within the system. The flaw stems from inadequate input validation and output sanitization mechanisms that fail to properly escape or filter user-supplied data before rendering it in web pages. Attackers can exploit this weakness by submitting malicious script code through the FAQ management interface, which then gets executed in the browsers of unsuspecting users who view the affected content. The vulnerability falls under the CWE-79 category of Cross-Site Scripting, specifically representing a stored XSS attack vector where malicious payloads are permanently stored on the server and executed whenever the compromised page is accessed. This type of vulnerability is particularly dangerous because it can persist indefinitely and affect multiple users without requiring them to click on any additional links or perform specific actions beyond visiting the compromised page. The attack surface extends beyond simple script execution to potentially enable more sophisticated attacks including session hijacking, credential theft, and redirection to malicious sites.
The technical implementation of this vulnerability demonstrates a classic failure in secure coding practices where user input is directly incorporated into dynamic web content without proper sanitization. The adm/faqmasterformupdate.php script likely accepts parameters through HTTP POST requests containing FAQ data and fails to validate or escape special characters that could be interpreted as HTML or JavaScript code. When administrators or users view the FAQ content, the unfiltered input gets rendered directly into the web page, creating an execution environment for malicious scripts. This flaw operates at the application layer and can be exploited through various vectors including direct injection into FAQ titles, descriptions, or other editable fields. The vulnerability's impact is amplified by the fact that it resides in an administrative interface, potentially allowing attackers to gain elevated privileges or manipulate the entire FAQ management system. According to ATT&CK framework methodology, this vulnerability maps to T1059.001 (Command and Scripting Interpreter: JavaScript) and T1566 (Phishing) as attackers can leverage the XSS to redirect users to malicious sites or steal session cookies. The persistent nature of stored XSS makes this vulnerability particularly attractive to threat actors as it can be weaponized for long-term access and data exfiltration.
The operational impact of CVE-2018-15581 extends far beyond simple script injection, potentially enabling comprehensive compromise of affected systems and user data. Successful exploitation can result in unauthorized access to administrative functions, data manipulation, and persistent backdoor establishment within the web application. Attackers can leverage the XSS to steal session cookies, allowing them to impersonate legitimate users and gain unauthorized access to the gnuboard5 administration panel. The vulnerability also creates opportunities for credential harvesting, where users unknowingly submit their login information to malicious endpoints. Furthermore, the compromised system can be used to deliver additional malware payloads, conduct phishing attacks, or serve as a pivot point for attacking other systems within the same network. The administrative nature of the vulnerable component increases the potential damage significantly, as attackers who successfully exploit this vulnerability could modify or delete FAQ content, potentially damaging the organization's reputation or disrupting service availability. Organizations using affected versions of gnuboard5 face risks of data breaches, regulatory compliance violations, and potential legal consequences due to inadequate security controls. The vulnerability's exploitation can occur without user interaction beyond visiting the compromised page, making it particularly insidious and difficult to detect through traditional security monitoring approaches.
Mitigation strategies for CVE-2018-15581 must address both immediate remediation and long-term security improvements to prevent similar vulnerabilities from emerging. The most critical immediate action involves upgrading to gnuboard5 version 5.3.1.6 or later, which contains the necessary patches to address the input validation and output sanitization deficiencies. Organizations should also implement comprehensive input validation mechanisms that sanitize all user-supplied data before processing, particularly in administrative interfaces where the risk of exploitation is highest. Output encoding should be implemented at all points where user data is rendered in web pages, ensuring that special characters are properly escaped to prevent interpretation as HTML or script code. Security headers such as Content Security Policy (CSP) should be configured to limit script execution and prevent unauthorized code injection. Regular security audits and penetration testing should be conducted to identify and remediate similar vulnerabilities in other components of the application. Additionally, implementing web application firewalls and intrusion detection systems can help detect and block exploitation attempts. The remediation process should include comprehensive testing to ensure that the patch does not introduce regression issues and that all existing functionality remains intact. Organizations should also consider implementing automated vulnerability scanning tools that can identify similar XSS vulnerabilities in other applications and web components. Training for development teams on secure coding practices, particularly regarding input validation and output sanitization, is essential to prevent recurrence of such vulnerabilities in future code development cycles.