Source: cve@mitre.org
Cross-site scripting (XSS) vulnerability in the web management interface in httpd/cgi-bin/ipinfo.cgi in Smoothwall Express 3.1 and 3.0 SP3 and earlier allows remote attackers to inject arbitrary web script or HTML via the IP parameter in a Run action.
Smoothwall Express 3.1 and earlier are vulnerable to a critical cross-site scripting (XSS) vulnerability in the web management interface. This flaw allows remote attackers to inject malicious JavaScript code into the web interface, potentially leading to account compromise, data theft, or complete system takeover if a privileged user is tricked into visiting a crafted link.
Step 1: Payload Delivery: The attacker crafts a malicious URL containing the XSS payload in the IP parameter. This URL targets the ipinfo.cgi script with a Run action.
The vulnerability stems from a lack of proper input validation and output encoding in the httpd/cgi-bin/ipinfo.cgi script within Smoothwall Express. Specifically, the script fails to sanitize the IP parameter when handling a Run action. This allows an attacker to inject arbitrary HTML or JavaScript code into the response. The injected code is then executed in the context of the victim's browser when they access the vulnerable page. The root cause is a missing or inadequate input validation mechanism for the IP parameter and a failure to encode the output before rendering it in the HTML response. This allows for cross-site scripting attacks.
While no specific APTs are directly linked to this CVE, XSS vulnerabilities are commonly used by various threat actors. The impact of this vulnerability could be used by any actor. This CVE is not listed in the CISA KEV catalog, but the age and nature of the vulnerability suggest that it could be a target for opportunistic attackers.
Monitor web server logs for suspicious activity, such as unusual requests to ipinfo.cgi with long or unusual IP parameter values.
Implement a Web Application Firewall (WAF) to detect and block XSS attempts.
Analyze network traffic for unusual HTTP requests containing JavaScript code within the IP parameter of requests to ipinfo.cgi.
Examine the HTML source code of the ipinfo.cgi response for injected JavaScript or HTML tags.
Use a vulnerability scanner to identify the presence of this vulnerability.
Upgrade to a patched version of Smoothwall Express (version 3.2 or later).
Implement input validation to sanitize the IP parameter, ensuring that it only accepts valid IP addresses and rejects any potentially malicious characters or code.
Implement output encoding (e.g., HTML entity encoding) to escape any special characters in the IP parameter before rendering it in the HTML response.
Apply the principle of least privilege, ensuring that users have only the necessary permissions to access the web management interface.
Regularly scan the system for vulnerabilities and apply security patches promptly.
Consider using a Content Security Policy (CSP) to mitigate the impact of XSS attacks.