Cross-site scripting (XSS) vulnerability in the View URL Database functionality in Sun Java System Web Proxy Server 4.x before 4.0.6 and 3.x before 3.6 SP11 allows remote attackers to inject arbitrary web script or HTML via unspecified vectors, aka BugID 6566309.
Sun Java System Web Proxy Server versions 4.x (prior to 4.0.6) and 3.x (prior to 3.6 SP11) are vulnerable to a Cross-Site Scripting (XSS) attack. This vulnerability allows attackers to inject malicious scripts into the web proxy, potentially leading to session hijacking, data theft, and website defacement for users accessing the proxy.
Step 1: Payload Delivery: An attacker crafts a malicious URL or data containing JavaScript or HTML code. This payload is designed to exploit the XSS vulnerability. Step 2: Input into URL Database: The attacker submits the malicious payload through a mechanism that allows it to be stored within the Web Proxy's URL database. This could involve manipulating a form, sending a specially crafted request, or exploiting another related vulnerability. Step 3: Database Storage: The Web Proxy Server stores the attacker's payload in the URL database without proper sanitization or encoding. Step 4: User Interaction: A legitimate user accesses the 'View URL Database' functionality within the Web Proxy Server's interface. Step 5: Payload Execution: The Web Proxy Server retrieves the stored malicious payload from the URL database and renders it in the user's browser. Because the payload is not properly sanitized, the browser interprets the injected JavaScript or HTML as part of the web page's content. Step 6: Exploitation: The injected JavaScript executes within the user's browser, allowing the attacker to perform actions on behalf of the user, such as stealing cookies, redirecting the user, or defacing the proxied web pages.
The vulnerability stems from insufficient input validation and output encoding within the 'View URL Database' functionality. Specifically, the application fails to properly sanitize user-supplied input before displaying it within the web interface. This allows an attacker to inject malicious JavaScript or HTML tags into the URL database entries. When a user views the URL database, the injected script executes within the context of the user's browser, enabling the attacker to perform actions on behalf of the user, such as stealing cookies, redirecting the user to a phishing site, or modifying the content of the proxied web pages. The root cause is a lack of proper input sanitization and output encoding (e.g., HTML escaping) when displaying the URL database entries. The application trusts the user-provided data without validating or encoding it, leading to the XSS vulnerability.