CVE-2006-2755 in Ubb.threads
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in index.php in UBBThreads 5.x and earlier allows remote attackers to inject arbitrary web script or HTML via the debug parameter, as demonstrated by stealing MD5 hashes of passwords.
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Analysis
by VulDB Data Team • 06/20/2019
The vulnerability identified as CVE-2006-2755 represents a critical cross-site scripting flaw within UBBThreads 5.x and earlier versions, specifically affecting the index.php script. This weakness resides in the improper handling of user-supplied input through the debug parameter, creating an avenue for malicious actors to execute arbitrary web scripts or HTML code within the context of affected web applications. The vulnerability demonstrates the classic characteristics of a reflected cross-site scripting attack where attacker-controlled data flows directly into the web application's output without adequate sanitization or encoding mechanisms.
The technical exploitation of this vulnerability occurs when an attacker crafts a malicious URL containing script code within the debug parameter of the index.php endpoint. When a victim clicks such a link and the application processes the debug parameter without proper validation, the injected script executes within the victim's browser session. This particular implementation allows attackers to steal MD5 hashes of passwords, indicating that the malicious code can access and exfiltrate sensitive session data or application information. The vulnerability's classification aligns with CWE-79, which specifically addresses Cross-Site Scripting flaws in software applications, and demonstrates the dangerous potential for credential theft and session hijacking attacks.
The operational impact of this vulnerability extends beyond simple script injection, as it provides attackers with the capability to perform session manipulation and credential theft operations. The ability to extract MD5 password hashes represents a significant security compromise since these hashes can be subjected to offline brute force attacks or rainbow table lookups to recover original passwords. This vulnerability directly impacts the confidentiality and integrity of user authentication data within the UBBThreads platform, potentially allowing unauthorized access to user accounts and administrative functions. The attack vector demonstrates the importance of input validation and output encoding in web application security, as the flaw exists in the application's core request processing logic.
Mitigation strategies for CVE-2006-2755 should prioritize immediate patching of affected UBBThreads installations to version 6.0 or later where the vulnerability has been addressed. Organizations should implement comprehensive input validation measures that sanitize all user-supplied parameters, particularly those used for debugging or administrative purposes. The implementation of proper output encoding techniques, such as HTML entity encoding, when rendering user data back to web browsers, serves as an effective defensive measure against reflected XSS attacks. Additionally, the deployment of web application firewalls and security headers including Content Security Policy can provide additional layers of protection. This vulnerability highlights the fundamental security principle that all user inputs must be treated as untrusted data and properly validated before processing, as recommended by the OWASP Top Ten project and ATT&CK framework category T1190 for Web Shell and T1566 for Phishing techniques that exploit similar input validation weaknesses.