CVE-2002-1374 in MySQL
Summary
by MITRE
The COM_CHANGE_USER command in MySQL 3.x before 3.23.54, and 4.x before 4.0.6, allows remote attackers to gain privileges via a brute force attack using a one-character password, which causes MySQL to only compare the provided password against the first character of the real password.
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Analysis
by VulDB Data Team • 03/23/2025
The vulnerability described in CVE-2002-1374 represents a critical authentication flaw in MySQL database systems that affected versions prior to 3.23.54 and 4.0.6. This issue stems from a fundamental weakness in the password validation mechanism where the system fails to properly compare the entire password string against the stored hash. The flaw specifically manifests during the COM_CHANGE_USER command execution, which is designed to allow users to switch between different database accounts while maintaining an active connection. This command serves as a legitimate administrative function but becomes a vector for privilege escalation when combined with the flawed comparison logic.
The technical implementation of this vulnerability exploits a well-known weakness in string comparison functions where MySQL performs only a partial comparison of passwords. When an attacker submits a password during the COM_CHANGE_USER operation, the system only evaluates the first character of the submitted password against the first character of the stored password hash. This primitive comparison mechanism creates a massive security gap that allows attackers to bypass authentication entirely by simply guessing the first character of the target user's password. The vulnerability essentially reduces the effective password entropy from the full password length to just a single character, making brute force attacks trivially successful.
From an operational perspective, this vulnerability creates severe implications for database security and compliance requirements. Organizations using affected MySQL versions face immediate risks of unauthorized access to sensitive data, potential data breaches, and violation of security standards such as those outlined in the CWE-254 category for weak authentication mechanisms. The attack vector is particularly dangerous because it requires minimal computational resources and can be executed remotely without prior access to the system. Security professionals should note that this vulnerability aligns with ATT&CK technique T1212 for exploitation of remote services, specifically targeting credential access through weak authentication.
The impact of this vulnerability extends beyond simple unauthorized access as it enables attackers to escalate privileges and potentially gain administrative control over database systems. Database administrators must consider the broader security implications when assessing the risk of such flaws, particularly in environments where database credentials are not adequately protected or where access controls are not properly implemented. The vulnerability demonstrates the critical importance of proper input validation and authentication mechanisms in database systems, as highlighted by industry standards such as NIST SP 800-53 controls for access control and authentication. Organizations should immediately implement patches to address this issue and conduct comprehensive security assessments of their database environments to identify any potential exploitation attempts.
Mitigation strategies for this vulnerability require immediate patching of affected MySQL installations to versions that properly implement full password comparison mechanisms. System administrators should also implement additional security controls including network segmentation, firewall rules limiting database access, and monitoring for unusual authentication patterns. The vulnerability underscores the necessity of maintaining up-to-date security patches and implementing proper security monitoring procedures to detect and respond to exploitation attempts. Organizations should also consider implementing multi-factor authentication mechanisms and regular security audits to prevent similar issues from occurring in other database components or systems.