Gnuboard CMS Cross-Site Scripting (XSS) Scanner

Gnuboard CMS is a widely used content management system, popular for its flexibility and community-driven support. It's actively used by various organizations for setting up their online forums, blogs, and business websites. Users appreciate its extensive features, modularity, and ease of customization, which makes it attractive for both developers and tech-savvy individuals. The platform allows straightforward integration with third-party services, enhancing its extensibility. Businesses utilize it to reach audiences across different geographies, ensuring critical web presence. The comprehensive documentation and vibrant user community contribute to its continuing evolution and functionality.

Cross-Site Scripting (XSS) is a prevalent web application vulnerability that allows malicious users to inject harmful scripts into web pages viewed by other users. This vulnerability can be exploited by attackers to execute arbitrary JavaScript in the context of another user's session. The principal aim of an attacker exploiting an XSS vulnerability is to hijack user sessions, deface websites, or redirect users to malicious sites. Even with a relatively moderate CVSS score, XSS can lead to severe consequences, compromising the integrity and security of a web application. Automating detection and remediation of XSS vulnerabilities is crucial for maintaining a robust security posture.

This vulnerability in Gnuboard CMS is linked to its handling of user inputs through the SMS plugin, specifically the `ajax.sms_emoticon.php` endpoint. Key parameters, like `arr_ajax_msg`, fail to properly sanitize input, making the platform vulnerable to injection of arbitrary JavaScript code. When exploited, this reveals potential oversight in input validation and encoding within the application. Attackers can leverage these vectors without the need for high-level privileges, indicating lower complexity in the execution. The application's susceptibility largely stems from insufficient output encoding, which results in script execution upon rendering of the page.

Exploiting this XSS vulnerability can lead to several adverse effects, including unauthorized access to user accounts and sensitive data disclosure. It can also allow attackers to conduct phishing attacks by presenting legitimate-looking pages that trick users into giving away credentials. Man-in-the-middle scenarios may arise, leading to a loss of data integrity and confidentiality. The reputation of affected websites can suffer significantly, causing user trust to dwindle. Additionally, persistent XSS might allow attackers to plant backdoors, creating more systemic risks and prolonged compromises.

REFERENCES

• https://sir.kr/g5_pds/4788?page=5
• https://github.com/gnuboard/gnuboard5/commit/8182cac90d2ee2f9da06469ecba759170e782ee3