CVE-2006-1894 in RevoBoard
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in RevoBoard 1.8, as derived from PunBB, allows remote attackers to inject arbitrary web script or HTML via a substitution cipher of the email tag, which is transformed when the application s e-mail address obfuscator reverses the transformation. NOTE: it is not clear whether this is a site-specific issue; however, the claimed codebase relationship with PunBB might be relevant.
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Analysis
by VulDB Data Team • 07/24/2018
The vulnerability identified as CVE-2006-1894 represents a cross-site scripting flaw within RevoBoard 1.8, a web application that inherits its codebase from PunBB. This security weakness resides in the email address obfuscation mechanism that the application employs to protect user contact information from spam bots. The vulnerability manifests when the application processes email addresses that have been encoded using a substitution cipher within the email tag, creating a scenario where attacker-controlled input can bypass the intended security measures. The flaw occurs specifically during the reversal of the transformation process, where the encoded email data is decoded and subsequently rendered without proper sanitization, allowing malicious scripts to execute within the context of other users' browsers.
The technical implementation of this vulnerability stems from inadequate input validation and output encoding within the application's email obfuscation routine. When users submit content containing email addresses encoded with substitution ciphers, the system's email address obfuscator component transforms these inputs but fails to properly sanitize the resulting output before rendering it in web pages. This failure creates a direct pathway for attackers to inject malicious JavaScript code or HTML content that executes when other users view the affected content. The vulnerability is classified under CWE-79 as a failure to sanitize user input before incorporating it into dynamic web content, specifically manifesting as a reflected cross-site scripting vector. The issue demonstrates a classic improper neutralization of special elements used in a web browser, where the application's attempt to protect email addresses inadvertently creates a security hole.
The operational impact of this vulnerability extends beyond simple script injection, as it enables attackers to perform various malicious activities within the context of affected users' sessions. An attacker could exploit this vulnerability to steal session cookies, redirect users to phishing sites, deface the application's content, or execute more sophisticated attacks such as credential harvesting. The remote nature of the attack means that exploitation does not require any local system access or privileged accounts, making it particularly dangerous for web applications that handle user-generated content. The vulnerability affects the application's ability to maintain secure communication channels and can compromise user privacy and data integrity. Given that RevoBoard 1.8 is derived from PunBB, this issue likely represents a broader class of vulnerabilities present in the PunBB codebase, potentially affecting other applications that share similar email obfuscation implementations and security practices.
Mitigation strategies for this vulnerability require immediate attention to the email obfuscation implementation and broader input validation measures. Organizations should implement proper output encoding for all user-generated content, particularly when dealing with email addresses and other data that may contain special characters. The recommended approach involves applying context-specific encoding before rendering any user-supplied content, ensuring that the substitution cipher mechanism does not introduce executable code into the final rendered output. Security patches should address the root cause by modifying the email address obfuscator to properly sanitize all input before transformation and by implementing comprehensive input validation that rejects potentially malicious content. Additionally, the application should adopt a whitelist-based approach to acceptable characters in email addresses and implement Content Security Policy headers to further limit the execution of unauthorized scripts. The vulnerability demonstrates the importance of secure coding practices and the need for thorough security testing of web applications, particularly those that implement custom security mechanisms such as email obfuscation. Organizations should also consider implementing web application firewalls and monitoring systems to detect and prevent exploitation attempts, while ensuring that all third-party components and derived codebases are regularly updated to address known vulnerabilities.