CVE-2016-6630 in phpMyAdmin
Summary
by MITRE
An issue was discovered in phpMyAdmin. An authenticated user can trigger a denial-of-service (DoS) attack by entering a very long password at the change password dialog. All 4.6.x versions (prior to 4.6.4), 4.4.x versions (prior to 4.4.15.8), and 4.0.x versions (prior to 4.0.10.17) are affected.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 10/05/2022
The vulnerability identified as CVE-2016-6630 represents a critical denial-of-service weakness within phpMyAdmin, a widely used web-based database management tool that serves as the de facto standard interface for managing mysql and mariadb databases across numerous web hosting environments and enterprise deployments. This flaw specifically targets the password change functionality within the application's user interface, creating a scenario where an authenticated attacker can deliberately exploit the system's processing capabilities through a seemingly benign action. The vulnerability affects multiple version lines including 4.0.x, 4.4.x, and 4.6.x, with specific patch versions required to remediate the issue. The impact extends beyond simple service disruption as it can potentially affect database availability for legitimate users and administrators who rely on phpMyAdmin for their database management tasks.
The technical nature of this vulnerability stems from inadequate input validation and processing within the password change dialog functionality. When an authenticated user submits an extremely long password string through the change password interface, the phpMyAdmin application fails to properly handle the excessive input length, leading to resource exhaustion or infinite processing loops. This type of flaw falls under the CWE-770 category of allocating resources without proper limits, where the application does not impose reasonable constraints on password length during processing. The vulnerability manifests as a resource consumption attack where the system's memory and processing power become overwhelmed by the malformed input, potentially causing the web server to become unresponsive or crash entirely. The weakness exists because the application's input sanitization routines do not adequately check for excessive string lengths before performing cryptographic operations or other resource-intensive processing required for password changes.
The operational impact of CVE-2016-6630 extends far beyond a simple service interruption, as it can severely disrupt database administration workflows and potentially compromise system availability for legitimate users. In production environments where phpMyAdmin serves as the primary interface for database management, this vulnerability could be exploited by malicious insiders or attackers who have gained valid authentication credentials. The DoS condition affects not just the specific user attempting the password change but can potentially impact the entire web application, making it difficult for other administrators to perform their duties. This vulnerability aligns with ATT&CK technique T1499.004 which involves network denial of service attacks, though in this case the attack vector operates through application-level resource exhaustion rather than network-level disruption. Organizations using affected versions of phpMyAdmin face significant operational risk, as database administrators may be unable to perform essential tasks during an active attack, potentially leading to extended downtime and service degradation.
Mitigation strategies for this vulnerability require immediate patching of affected phpMyAdmin versions to the recommended secure releases, specifically versions 4.0.10.17, 4.4.15.8, and 4.6.4 or later. Organizations should implement additional protective measures including input length validation at the application level, rate limiting for password change operations, and monitoring for unusual password length patterns that may indicate exploitation attempts. Network-level protections such as web application firewalls can help detect and block malicious password length inputs, while security monitoring should be implemented to identify potential DoS attack patterns. The vulnerability highlights the importance of proper input validation and resource management in web applications, particularly those handling user authentication data. Organizations should also consider implementing automated patch management systems to ensure timely deployment of security updates and maintain comprehensive inventory tracking of all phpMyAdmin installations within their infrastructure to prevent similar vulnerabilities from persisting across multiple systems.