Source: cna@vuldb.com
A vulnerability was found in xnx3 wangmarket up to 6.4. This affects an unknown function of the file /siteVar/save.do of the component Add Global Variable Handler. The manipulation of the argument Remark/Variable Value results in cross site scripting. The attack can be executed remotely. The exploit has been made public and could be used. The vendor was contacted early about this disclosure but did not respond in any way.
Xnx3 Wangmarket versions up to 6.4 are vulnerable to a critical cross-site scripting (XSS) flaw. This vulnerability, located in the /siteVar/save.do component, allows attackers to inject malicious scripts via the Remark/Variable Value parameter, potentially leading to account compromise and data theft through remote exploitation.
Step 1: Payload Delivery: An attacker crafts a malicious payload containing JavaScript code (e.g., <script>alert('XSS')</script>) and submits it through a specially crafted HTTP request to the /siteVar/save.do endpoint, targeting the Remark/Variable Value parameter.
Step 2: Data Storage: The vulnerable application stores the attacker's malicious payload within the database, associated with the global variable.
Step 3: Payload Retrieval: When a legitimate user accesses a page that displays the global variable (e.g., a page that renders the Remark/Variable Value), the application retrieves the stored payload from the database.
Step 4: Malicious Code Execution: The application renders the retrieved data without proper sanitization. The attacker's JavaScript code is executed within the user's browser, in the context of the vulnerable website. This allows the attacker to steal cookies, redirect users, or perform other malicious actions.
The vulnerability stems from insufficient input validation and output encoding within the Add Global Variable Handler functionality of xnx3 wangmarket. Specifically, the application fails to properly sanitize user-supplied input provided through the Remark/Variable Value parameter before rendering it on a webpage. This allows attackers to inject arbitrary HTML and JavaScript code. The root cause is a lack of proper input validation and output encoding (e.g., HTML escaping) when handling the Remark/Variable Value parameter. The application directly incorporates user-controlled data into the HTML response without sanitization, leading to the execution of malicious scripts within the context of the vulnerable website. This is a classic example of a stored XSS vulnerability, as the injected payload is stored on the server and served to other users.
While no specific APTs are directly linked to this CVE, the public availability of the exploit code and the vendor's lack of response make it attractive to various threat actors. This vulnerability could be used by attackers for phishing, credential harvesting, and malware distribution. The lack of vendor response suggests a high probability of continued exploitation. This vulnerability is not currently listed in the CISA KEV catalog, but the risk of inclusion is high given the public exploit and lack of vendor response.
Monitor web server logs for suspicious POST requests to /siteVar/save.do with unusual payloads in the Remark/Variable Value parameter, specifically looking for HTML tags or JavaScript code.
Implement a Web Application Firewall (WAF) with rules to detect and block XSS payloads.
Analyze network traffic for unusual HTTP requests containing potentially malicious JavaScript code.
Monitor for changes in the application's behavior, such as unexpected redirects or pop-up windows.
Implement Content Security Policy (CSP) to mitigate the impact of XSS attacks.
Implement robust input validation to sanitize all user-supplied data, especially the Remark/Variable Value parameter. This includes filtering out or encoding special characters that could be interpreted as HTML or JavaScript.
Implement output encoding (e.g., HTML escaping) to ensure that user-supplied data is rendered safely in the browser.
Apply the principle of least privilege, ensuring that the application only has the necessary permissions.
Update to a patched version of xnx3 wangmarket, if available. If no patch is available, consider alternative web content management systems.
Implement a Web Application Firewall (WAF) to filter malicious requests.
Review and update the Content Security Policy (CSP) to prevent the execution of unauthorized scripts.