CVE-2006-7076 in phpBB Advanced Guestbook
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in guestbook.php in Advanced Guestbook 2.4 for phpBB allows remote attackers to inject arbitrary web script or HTML via the entry parameter. NOTE: this issue might be resultant from SQL injection.
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Analysis
by VulDB Data Team • 10/13/2017
The CVE-2006-7076 vulnerability represents a critical cross-site scripting flaw in the Advanced Guestbook 2.4 component for phpBB, specifically affecting the guestbook.php script. This vulnerability enables remote attackers to execute malicious web scripts or HTML code within the context of other users' browsers, creating a significant security risk for web applications that rely on user-generated content. The vulnerability manifests through the entry parameter, which serves as an injection vector for malicious payloads that can be executed when legitimate users view the guestbook entries.
The technical flaw stems from insufficient input validation and output sanitization within the guestbook.php script. When user-submitted data is processed through the entry parameter without proper sanitization, the application fails to neutralize potentially malicious content that could contain script tags or other executable code. This weakness allows attackers to craft specially formatted entries that, when rendered by the application, execute unintended commands in the victim's browser context. The vulnerability operates at the application layer, specifically targeting the web interface where user interactions are processed and displayed.
The operational impact of this vulnerability extends beyond simple script execution, potentially enabling attackers to perform session hijacking, deface web applications, steal sensitive cookies, or redirect users to malicious sites. Given that the vulnerability affects a guestbook component, it represents a persistent threat as legitimate users may unknowingly encounter malicious content during normal browsing activities. The risk is amplified by the fact that guestbook applications often serve as public-facing interfaces where users expect to see benign content, making the execution of malicious scripts more likely to succeed due to reduced user suspicion.
This vulnerability aligns with CWE-79, which specifically addresses Cross-Site Scripting flaws in software applications, and demonstrates characteristics consistent with the attack patterns documented in the MITRE ATT&CK framework under the technique of Web Application Attack. The potential for SQL injection mentioned in the advisory suggests that this vulnerability might represent a broader class of input validation issues that could compound the security risk. Organizations should implement comprehensive input validation measures, output encoding, and proper parameter sanitization to address this weakness. The recommended mitigations include validating all user inputs through whitelisting approaches, implementing proper HTML escaping for dynamic content, and regularly updating vulnerable components to ensure that known security flaws are addressed through patches and security updates.