CVE-2006-4038 in GaesteChaos
Summary
by MITRE
Multiple cross-site scripting (XSS) vulnerabilities in eintragen.php in GaesteChaos 0.2 and earlier allow remote attackers to inject arbitrary web script or HTML via the (1) gastname or (2) gastwohnort parameters.
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Analysis
by VulDB Data Team • 08/02/2018
The vulnerability identified as CVE-2006-4038 represents a critical security flaw in the GaesteChaos guestbook application version 0.2 and earlier. This issue manifests as multiple cross-site scripting vulnerabilities that specifically target the eintragen.php script, which serves as the primary entry point for guestbook submissions. The vulnerability affects the application's handling of user input parameters, creating a pathway for malicious actors to execute arbitrary web scripts or HTML code within the context of other users' browsers. This type of vulnerability directly violates the fundamental principles of web application security and represents a classic example of insufficient input validation and output encoding.
The technical implementation of this vulnerability stems from the application's failure to properly sanitize or escape user-supplied data before incorporating it into dynamic web page content. Attackers can exploit this weakness by submitting malicious payloads through the gastname parameter or the gastwohnort parameter, which are designed to collect guest names and addresses respectively. When these parameters are processed and displayed without adequate security measures, the injected scripts execute in the browsers of other users who view the affected pages. This vulnerability maps directly to CWE-79, which specifically addresses Cross-Site Scripting flaws, and demonstrates the classic pattern of unsafe direct object reference or improper input handling that has plagued web applications for decades. The attack vector operates entirely through standard HTTP request parameters, making it accessible to attackers with minimal technical expertise and requiring no special tools beyond basic web browsing capabilities.
The operational impact of this vulnerability extends far beyond simple data corruption or display issues. Successful exploitation enables attackers to perform a range of malicious activities including session hijacking, credential theft, redirection to malicious sites, and potential data exfiltration from users' browsers. The vulnerability creates a persistent threat that can affect all users who interact with the guestbook application, as any visitor who views the compromised entries becomes a potential victim of the injected scripts. This type of vulnerability also provides attackers with a platform for more sophisticated attacks, such as using the compromised application as a launching point for further reconnaissance or as a vector for phishing campaigns. The vulnerability affects the availability and integrity of the application's data, as well as the confidentiality of user interactions, making it a critical concern for any organization relying on guestbook functionality or similar user-submitted content systems. The attack methodology aligns with ATT&CK technique T1566.001 for credential access through web application attacks, and demonstrates how seemingly simple input fields can become attack surfaces for broader compromise.
Mitigation strategies for this vulnerability must address both immediate remediation and long-term security improvements. The primary fix involves implementing proper input validation and output encoding for all user-supplied parameters, ensuring that any potentially dangerous characters or script tags are either rejected or properly escaped before being rendered in web pages. Organizations should implement a comprehensive input sanitization framework that validates data types, lengths, and character sets against strict whitelists. Additionally, the application should employ proper output encoding techniques such as HTML entity encoding when displaying user data, which prevents browsers from interpreting injected script code as executable instructions. Security headers including Content Security Policy should be implemented to further restrict script execution and reduce the impact of any remaining vulnerabilities. Regular security testing and code reviews should be conducted to identify similar issues in other parts of the application, and the system should be upgraded to a supported version of GaesteChaos that addresses these security concerns. The vulnerability serves as a reminder of the critical importance of input validation and output encoding practices, which remain fundamental defense mechanisms against XSS attacks and are essential components of any robust web application security posture.