CVE-2021-3831 Scanner

Gnuboard 5 is a popular web-based bulletin board system widely used for creating and managing online communities, forums, and websites. It is primarily used by web developers and administrators to provide a platform for user-generated content. The software facilitates user interactions, content sharing, and discussions on various topics. It is employed by a variety of organizations, including educational institutions, businesses, and hobbyist communities, who require a versatile and customizable forum solution. With its comprehensive feature set, Gnuboard 5 includes functionalities for managing posts, user accounts, and customizable themes. However, like any complex web application, security plays a crucial role in its operation and maintenance.

Cross-Site Scripting (XSS) is a prevalent web vulnerability that allows attackers to inject malicious scripts into web pages viewed by other users. These scripts can potentially access and manipulate the session cookies, tokens, or other sensitive information of the logged-in users. The vulnerability in question occurs due to insufficient input validation in the $_GET['LGD_OID'] parameter within Gnuboard 5. By exploiting this weakness, attackers can execute arbitrary scripts on the web browser of any user visiting the affected page. Such vulnerabilities pose serious security risks, leading to unauthorized actions performed on behalf of a user or exposing their private data.

The vulnerability is specifically found in the 'mobile/shop/lg/mispwapurl.php' script, where the 'LGD_OID' parameter is mishandled. An attacker can craft a URL with a payload that includes script tags, thereby triggering the execution of arbitrary JavaScript code. The XSS attack is facilitated by the lack of proper encoding or validation of user-supplied input, allowing script injection. When a victim navigates to the compromised endpoint, the malicious script is executed within their context. The server's failure to sanitize input at this endpoint makes it susceptible to XSS attacks, leading to risks of content manipulation and user impersonation.

If exploited, an XSS vulnerability like this one can have several adverse effects. Attackers may steal session cookies or tokens, allowing them to impersonate users or escalate privileges within the application. They can manipulate content on the page, redirect users to malicious sites, or engage in clickjacking attempts. Additionally, XSS can be a vector to distribute malware or perpetrate phishing attacks by mimicking legitimate content. The impact of such exploitation can compromise the integrity, confidentiality, and availability of the web application and its user base.

REFERENCES

• https://huntr.dev/bounties/ed317cde-9bd1-429e-b6d3-547e72534dd5/
• https://vulners.com/huntr/25775287-88CD-4F00-B978-692D627DFF04
• https://nvd.nist.gov/vuln/detail/CVE-2021-3831