CVE-2006-2764 in GuestbookXL
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in GuestbookXL 1.3 allows remote attackers to inject arbitrary web script or HTML via a javascript URI in an IMG tag in a comment field to (1) guestwrite.php or (2) guestbook.php.
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Analysis
by VulDB Data Team • 07/28/2018
The vulnerability identified as CVE-2006-2764 represents a critical cross-site scripting flaw in GuestbookXL version 1.3, a web application designed for user comment submission and guestbook management. This vulnerability resides in the application's handling of user input within comment fields, specifically when processing image tags that contain javascript URIs. The flaw enables remote attackers to execute malicious scripts in the context of other users' browsers, potentially compromising the security of the entire application ecosystem.
The technical implementation of this vulnerability stems from insufficient input validation and output encoding within the guestbook.php and guestwrite.php script files. When users submit comments containing image tags with javascript URIs, the application fails to properly sanitize or escape these inputs before rendering them in the web page context. This allows attackers to embed malicious javascript code within the src attribute of img tags, which executes when other users view the guestbook entries. The vulnerability specifically targets the comment field processing functionality, making it particularly dangerous as it directly affects user-generated content that is displayed to multiple visitors.
From an operational impact perspective, this XSS vulnerability creates significant security risks for organizations using GuestbookXL 1.3. Attackers can exploit this flaw to steal session cookies, redirect users to malicious websites, deface the guestbook content, or perform actions on behalf of authenticated users. The vulnerability affects both guestwrite.php and guestbook.php endpoints, meaning the attack surface is broad and can potentially compromise the entire user interaction flow within the application. This type of vulnerability can lead to persistent security breaches where malicious scripts remain active until the application is patched or the compromised entries are manually removed.
The vulnerability maps directly to CWE-79, which specifically addresses cross-site scripting flaws in web applications, and aligns with ATT&CK technique T1566.001 for initial access through web application attacks. Organizations should implement immediate mitigations including input validation that strips or encodes javascript protocols from image src attributes, output encoding for all user-generated content, and regular security audits of web applications. Additionally, the application should be updated to a patched version or replaced with a more secure alternative, as the vulnerability represents a fundamental flaw in input handling that cannot be adequately protected through perimeter defenses alone. The risk assessment should consider the potential for credential theft and the possibility of further exploitation through session hijacking or privilege escalation attacks.