CVE-2009-0853 in CelerBB
Summary
by MITRE
login.php in CelerBB 0.0.2, when magic_quotes_gpc is disabled, allows remote attackers to bypass authentication and obtain administrative access via special characters in the Username parameter, as demonstrated by an admin # parameter value.
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Analysis
by VulDB Data Team • 11/24/2024
The vulnerability identified as CVE-2009-0853 affects CelerBB version 0.0.2, a web-based bulletin board system that suffers from a critical authentication bypass flaw. This issue specifically manifests when the PHP configuration parameter magic_quotes_gpc is disabled, creating a dangerous condition where user input is not properly sanitized before being processed by the application's authentication mechanism. The vulnerability resides within the login.php script which handles user authentication requests and fails to adequately validate or escape special characters in the Username parameter.
The technical exploitation of this vulnerability leverages the absence of proper input sanitization when magic_quotes_gpc is disabled, allowing attackers to inject special characters that manipulate the SQL query execution flow. When an attacker submits a username value containing characters such as the hash symbol #, the application processes this input without proper escaping, effectively commenting out the remainder of the SQL statement. This behavior enables unauthorized access to administrative accounts by exploiting the lack of input validation in the authentication routine, as the system does not properly handle or escape special characters that could alter the intended query execution path.
The operational impact of this vulnerability is severe and far-reaching, as it provides remote attackers with complete administrative access to the affected bulletin board system. Once exploited, attackers can gain full control over user accounts, modify or delete content, access sensitive information, and potentially use the compromised system as a foothold for further attacks within the network. The vulnerability affects the fundamental security principle of authentication, allowing unauthorized users to bypass the normal access control mechanisms and assume administrative privileges without proper credentials. This compromise directly violates the CIA triad by undermining the system's integrity and confidentiality.
This vulnerability aligns with CWE-89, which describes SQL injection flaws occurring when user-supplied data is not properly escaped before being incorporated into SQL queries. The attack pattern corresponds to the ATT&CK technique T1190 - Exploit Public-Facing Application, where adversaries target web applications to gain unauthorized access. Additionally, this issue demonstrates the importance of input validation and proper data sanitization practices, as outlined in the OWASP Top Ten security risks. The specific exploitation method involving the hash character to comment out SQL portions represents a classic SQL injection technique that has been documented extensively in cybersecurity literature and threat intelligence reports.
Mitigation strategies for this vulnerability require immediate implementation of proper input validation and sanitization measures. System administrators should ensure that magic_quotes_gpc is enabled or implement comprehensive input filtering using prepared statements and parameterized queries to prevent SQL injection attacks. The application code must be updated to properly escape or validate all user input, particularly in authentication mechanisms. Additionally, implementing proper access controls, regular security audits, and input validation libraries can help prevent similar vulnerabilities from occurring in the future. Regular patch management and security assessments are essential to maintaining the integrity of web applications and protecting against known vulnerabilities in third-party software components.