CVE-2008-5433 in PunBB
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in login.php in PunBB 1.3 and 1.3.1 allows remote attackers to inject arbitrary web script or HTML via the password field.
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Analysis
by VulDB Data Team • 10/21/2018
The CVE-2008-5433 vulnerability represents a critical cross-site scripting flaw discovered in PunBB forum software versions 1.3 and 1.3.1. This vulnerability specifically targets the login.php script and exploits a weakness in input validation that occurs when processing the password field parameter. The flaw enables remote attackers to inject malicious web scripts or HTML content into the application's response, creating a persistent security risk for users interacting with the vulnerable forum platform.
This vulnerability falls under the CWE-79 category of Cross-Site Scripting, which is classified as a weakness in web applications that allow arbitrary code execution within the context of other users' browsers. The technical implementation involves insufficient sanitization of user input in the password field, where the application fails to properly escape or validate special characters that could be interpreted as HTML or JavaScript code. When a user submits a password containing malicious script tags, the application processes this input without adequate filtering mechanisms, leading to the execution of unauthorized code in the victim's browser context.
The operational impact of this vulnerability extends beyond simple data theft or defacement, as it creates a persistent vector for various advanced attacks. Attackers can leverage this flaw to steal session cookies, redirect users to malicious sites, perform actions on behalf of authenticated users, or even establish persistent backdoors within the forum environment. The vulnerability affects all users who interact with the login functionality, making it particularly dangerous for community forums where users may have varying levels of security awareness. From an attacker's perspective, this vulnerability aligns with ATT&CK technique T1566.001 for initial access through credential harvesting, and T1059.001 for command and scripting interpreter usage in executing malicious payloads.
The exploitation process requires minimal technical expertise, as attackers only need to submit malicious input in the password field during the login process. This makes the vulnerability particularly dangerous for widespread exploitation, as it can be triggered by any user attempting to log in to the affected system. The vulnerability demonstrates a fundamental flaw in the application's security architecture, specifically in its input handling and output encoding mechanisms. Organizations using vulnerable PunBB versions face significant risk of user data compromise, potential account takeovers, and reputational damage due to the persistent nature of the vulnerability. The attack surface is broad since the vulnerability affects the core authentication mechanism, meaning that any user interaction with the login process could potentially be exploited.
Mitigation strategies should include immediate implementation of input validation and output encoding measures to prevent script injection in all user-supplied data fields. The most effective remediation involves proper HTML escaping of all dynamic content before rendering it in web pages, specifically implementing context-appropriate encoding for the password field and other user input parameters. Security patches should be applied immediately to upgrade to patched versions of PunBB, as the vulnerability has been addressed in subsequent releases. Additional protective measures include implementing content security policies, regular security audits of input validation mechanisms, and user education about the risks of submitting unexpected input to web applications. Organizations should also consider implementing web application firewalls and monitoring for suspicious input patterns to detect potential exploitation attempts. The vulnerability highlights the critical importance of proper input validation and output encoding in web applications, serving as a reminder that even seemingly benign input fields like password fields require comprehensive security consideration to prevent exploitation.