CVE-2009-4869 in Nasim Guest Book
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in index.php in Nasim Guest Book 1.2 allows remote attackers to inject arbitrary web script or HTML via the page parameter.
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Analysis
by VulDB Data Team • 07/13/2025
The CVE-2009-4869 vulnerability represents a classic cross-site scripting flaw in the Nasim Guest Book 1.2 web application that exposes users to potential malicious code execution. This vulnerability specifically affects the index.php script where the page parameter is processed without adequate input validation or output sanitization. The flaw enables remote attackers to inject arbitrary web scripts or HTML content directly into the guest book interface, creating a persistent threat vector that can compromise user sessions and data integrity. The vulnerability stems from the application's failure to properly escape or filter user-supplied input before rendering it within the web page context, making it susceptible to XSS attacks that can be exploited across different browser environments.
This vulnerability falls under CWE-79 which specifically addresses Cross-Site Scripting flaws in web applications. The technical implementation of this vulnerability demonstrates a failure in the application's input validation mechanisms where the page parameter is directly incorporated into the HTML output without proper sanitization. The flaw exists in the server-side processing logic where user input is treated as trusted content rather than potentially malicious data. Attackers can leverage this weakness by crafting malicious payloads that when executed in a victim's browser context can perform actions such as stealing session cookies, redirecting users to malicious sites, or defacing the guest book interface with unauthorized content. The vulnerability's impact is amplified by the fact that it affects the core functionality of the guest book application, making it a persistent threat vector for all users interacting with the system.
The operational impact of CVE-2009-4869 extends beyond simple data corruption or display issues, as it creates a foundation for more sophisticated attacks within the application's user base. When exploited, this vulnerability can lead to session hijacking where attackers gain unauthorized access to user accounts, potentially compromising the entire guest book system. The persistent nature of the vulnerability means that any user who views the compromised page will be exposed to the injected malicious content, creating a chain reaction effect that can spread the attack across multiple users. Additionally, the vulnerability can be exploited to deliver malware payloads or phishing content that can further compromise user systems and network security. The attack surface is particularly concerning given that guest book applications typically have broad user interaction, making the exploitation of this vulnerability more likely to affect a larger number of potential victims.
Mitigation strategies for CVE-2009-4869 must address both the immediate security gap and implement comprehensive input validation measures. The primary remediation involves implementing proper output encoding and input validation on all user-supplied parameters, particularly the page parameter in this case. Organizations should employ context-specific encoding mechanisms such as HTML entity encoding for content rendered in HTML contexts, and JavaScript encoding for content used in script contexts. The implementation should follow the principle of least privilege where user input is strictly validated against expected formats and sanitized before processing. Security measures should include input length limitations, character set restrictions, and regular security audits of web applications. Additionally, implementing Content Security Policy (CSP) headers can provide an additional layer of protection by restricting the sources from which scripts can be loaded, thereby limiting the impact of successful XSS attacks. The vulnerability also underscores the importance of keeping web applications updated and following secure coding practices that prevent similar issues from occurring in future versions of the software.