CVE-2011-5026 in Winn GuestBook
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in the addPost function in data/functions.php in Winn GuestBook before 2.4.8d allows remote attackers to inject arbitrary web script or HTML via the name parameter to index.php. NOTE: some of these details are obtained from third party information.
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Analysis
by VulDB Data Team • 01/26/2025
The CVE-2011-5026 vulnerability represents a classic cross-site scripting flaw within the Winn GuestBook application, specifically targeting the addPost function in the data/functions.php file. This vulnerability exists in versions prior to 2.4.8d and demonstrates a critical weakness in input validation and output sanitization mechanisms. The flaw allows remote attackers to execute malicious web scripts or HTML code through manipulation of the name parameter in the index.php file, effectively creating a persistent XSS vector that can compromise user sessions and data integrity.
The technical exploitation of this vulnerability occurs through the improper handling of user input within the guestbook's posting functionality. When users submit entries through the guestbook interface, the name parameter is not adequately sanitized or escaped before being rendered back to other users browsing the guestbook. This creates an environment where attackers can inject malicious payloads that execute in the context of other users' browsers. The vulnerability maps directly to CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting'), which is one of the most prevalent and dangerous web application security flaws. The attack vector operates through the standard XSS exploitation technique where malicious code is embedded in the name field and subsequently executed when other users view the guestbook entries.
The operational impact of this vulnerability extends beyond simple script injection, as it enables attackers to perform session hijacking, steal sensitive information, redirect users to malicious sites, or deface the guestbook content. The persistent nature of the vulnerability means that once exploited, the malicious scripts remain active until the affected guestbook is updated or the entries are deleted. This makes the vulnerability particularly dangerous in environments where guestbooks are publicly accessible and frequently visited by multiple users. The vulnerability also aligns with ATT&CK technique T1531 - Run Virtual Machine from Memory, as attackers can leverage the XSS to establish a foothold in user environments through browser-based attacks. Additionally, the flaw represents a significant risk to user privacy and application integrity, potentially allowing attackers to harvest cookies, session tokens, or other sensitive data transmitted by users.
Mitigation strategies for CVE-2011-5026 should prioritize immediate patching of the Winn GuestBook application to version 2.4.8d or later, which contains the necessary input validation fixes. Organizations should implement comprehensive input sanitization measures including proper HTML escaping of all user-supplied data before rendering it in web pages. The implementation of Content Security Policy (CSP) headers can provide an additional layer of protection against XSS attacks by restricting the sources from which scripts can be executed. Regular security assessments and input validation testing should be conducted to prevent similar vulnerabilities from emerging in other application components. Additionally, the principle of least privilege should be enforced, ensuring that guestbook applications do not have unnecessary permissions that could be exploited to escalate attacks beyond the initial XSS vector. The vulnerability highlights the critical importance of proper input validation and output encoding in web applications, as outlined in the OWASP Top Ten Project's emphasis on XSS prevention techniques.