CVE-2002-0551 in Dynamic Guestbook
Summary
by MITRE
Cross-site scripting vulnerability in Dynamic Guestbook 3.0 allows remote attackers to execute code in clients who access guestbook pages via the parameters (1) name, (2) mail, or (3) kommentar.
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Analysis
by VulDB Data Team • 09/16/2025
The CVE-2002-0551 vulnerability represents a classic cross-site scripting flaw in the Dynamic Guestbook 3.0 web application that fundamentally undermines user security through improper input validation. This vulnerability exists within the guestbook's parameter handling mechanism where the application fails to sanitize user-supplied data before incorporating it into web page responses. The affected parameters name, mail, and kommentar serve as entry points for malicious input that can be exploited to inject arbitrary script code into client-side browser environments. The vulnerability classifies under CWE-79 which specifically addresses cross-site scripting weaknesses in web applications, making it a direct descendant of well-established web security flaws that have plagued software development for decades.
The technical exploitation of this vulnerability occurs when remote attackers craft malicious input strings containing script code within the vulnerable parameters and submit them through the guestbook submission interface. When legitimate users subsequently access the guestbook pages containing these malicious entries, their browsers execute the injected scripts within the context of the vulnerable application. This execution environment provides attackers with the ability to perform actions such as stealing session cookies, redirecting users to malicious sites, defacing the guestbook content, or executing unauthorized operations on behalf of the victim. The vulnerability's impact extends beyond simple data theft to encompass complete client-side compromise, as the script execution occurs within the trusted context of the guestbook application.
From an operational perspective, this vulnerability creates significant risk for organizations deploying Dynamic Guestbook 3.0 in production environments where user-generated content is accepted. The attack surface expands with each guestbook entry, as every submitted comment becomes a potential vector for malicious code delivery. Security practitioners should note that this vulnerability aligns with ATT&CK technique T1566.001 which covers social engineering via malicious content, and T1059.007 which involves scripting through web shells. The vulnerability's persistence is particularly concerning as malicious scripts remain embedded in the guestbook entries and continue to execute whenever the affected pages are accessed, creating a continuous threat vector that can be leveraged for prolonged attacks.
Mitigation strategies for CVE-2002-0551 require immediate implementation of input validation and output encoding mechanisms throughout the application. The most effective approach involves sanitizing all user input through proper encoding techniques such as HTML entity encoding before rendering any content in web pages. Organizations should implement comprehensive parameter validation that rejects or sanitizes potentially malicious input patterns including common script tags, javascript protocols, and other suspicious character sequences. Additionally, the application should employ Content Security Policy headers to prevent unauthorized script execution and implement proper access controls to restrict guestbook submission to authorized users only. The vulnerability's age necessitates immediate remediation through application updates or complete replacement of the Dynamic Guestbook 3.0 software, as no patches exist for this specific version and the underlying architectural flaws remain unaddressed in legacy implementations.