Source: cve@mitre.org
Cross-site scripting (XSS) vulnerability in Sun Java System Web Proxy Server 3.6 before SP11 on Windows allows remote attackers to inject arbitrary web script or HTML via unspecified vectors, aka BugID 6611356.
Sun Java System Web Proxy Server 3.6 on Windows is vulnerable to a cross-site scripting (XSS) attack, allowing attackers to inject malicious code into web pages viewed by users. This vulnerability could lead to account compromise, data theft, or malware distribution by exploiting trust relationships between users and the proxy server. Successful exploitation requires no authentication and can impact all users of the proxy server.
Step 1: Payload Delivery: The attacker crafts a malicious URL or HTTP request containing a specially crafted payload designed to exploit the XSS vulnerability. This payload typically includes HTML tags and JavaScript code, such as <script>alert('XSS')</script>.
Step 2: Request Processing: The attacker sends the crafted request to the vulnerable Sun Java System Web Proxy Server.
Step 3: Input Handling: The proxy server receives the request and processes the input, which may include parameters or data intended for display or processing.
Step 4: Insufficient Sanitization: The server fails to properly validate or sanitize the attacker-controlled input. The malicious payload is not filtered or escaped.
Step 5: Response Generation: The server generates an HTTP response that includes the attacker's payload, often within the context of a web page or error message.
Step 6: Response Delivery: The server sends the response, including the malicious payload, to the victim's web browser.
Step 7: Payload Execution: The victim's web browser receives the response and, due to the lack of sanitization, executes the attacker's JavaScript code. This allows the attacker to perform actions on behalf of the victim, such as stealing cookies, redirecting the user, or defacing the website.
The vulnerability stems from insufficient input validation and output encoding within the Sun Java System Web Proxy Server 3.6 before SP11 on Windows. The server fails to properly sanitize user-supplied data before rendering it in the HTML response. This allows attackers to inject malicious JavaScript or HTML code, which is then executed by the victim's browser. The root cause is likely a missing or inadequate implementation of input validation and output encoding mechanisms, specifically failing to escape special characters like < and > in user-supplied input. This allows the attacker to craft a payload that, when rendered by the browser, executes arbitrary JavaScript code in the context of the proxy server's domain. The lack of proper sanitization allows the attacker to bypass security measures and execute malicious scripts.
While no specific APTs are directly linked to this specific CVE, XSS vulnerabilities are commonly used by various threat actors. This type of vulnerability is often used in the initial stages of an attack, such as phishing campaigns or watering hole attacks. CISA KEV status: Not Listed.
Monitor web server logs for suspicious HTTP requests containing common XSS payloads (e.g., <script>, onerror, javascript:).
Analyze network traffic for unusual HTTP requests with potentially malicious JavaScript code in parameters or headers.
Implement a Web Application Firewall (WAF) to detect and block XSS attempts.
Monitor for changes in the proxy server's configuration or behavior that could indicate compromise.
Use a vulnerability scanner to identify the presence of this vulnerability.
Upgrade to Sun Java System Web Proxy Server 3.6 SP11 or later, which includes a fix for this vulnerability.
Implement robust input validation to sanitize all user-supplied data before processing or displaying it.
Employ output encoding (e.g., HTML encoding) to escape special characters in user-supplied data before rendering it in HTML responses.
Use a Web Application Firewall (WAF) to detect and block XSS attempts.
Regularly scan the web server for vulnerabilities.
Implement the principle of least privilege to limit the impact of a successful XSS attack.