CVE-2016-9863 in phpMyAdmin
Summary
by MITRE
An issue was discovered in phpMyAdmin. With a very large request to table partitioning function, it is possible to invoke a Denial of Service (DoS) attack. All 4.6.x versions (prior to 4.6.5) are affected.
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Analysis
by VulDB Data Team • 06/23/2019
The vulnerability identified as CVE-2016-9863 represents a critical denial of service weakness within phpMyAdmin versions 4.6.x prior to 4.6.5. This flaw specifically targets the table partitioning functionality, which is a sophisticated database management feature used to divide large tables into smaller, more manageable segments. The vulnerability arises from insufficient input validation and resource handling within the partitioning implementation, creating a scenario where malicious actors can exploit the system by submitting excessively large requests that overwhelm the application's processing capabilities. This weakness falls under the category of resource exhaustion attacks, where the attacker consumes system resources to the point of rendering the service unavailable to legitimate users.
The technical exploitation of this vulnerability occurs when phpMyAdmin processes partitioning requests that contain unusually large datasets or complex partitioning parameters. The application fails to properly validate the size and complexity of these requests, allowing attackers to craft inputs that cause the system to consume excessive memory and processing power. This behavior can be categorized as a CWE-400 vulnerability, specifically related to uncontrolled resource consumption, which is a fundamental weakness in resource management that leads to denial of service conditions. The flaw is particularly dangerous because it can be triggered through normal administrative operations, making it difficult to distinguish between legitimate usage and malicious attacks.
The operational impact of CVE-2016-9863 extends beyond simple service disruption to potentially compromise the entire database management environment. When exploited successfully, the denial of service condition can prevent database administrators from performing critical maintenance tasks, accessing partitioned tables, or even logging into the phpMyAdmin interface. This vulnerability affects organizations that rely on phpMyAdmin for database administration, particularly those managing large datasets where partitioning is commonly used for performance optimization. The attack vector is relatively simple to execute, requiring only a properly crafted request to the partitioning function, which makes it an attractive target for attackers seeking to disrupt database operations. The vulnerability also aligns with ATT&CK technique T1499.004, which covers network denial of service attacks, as the exploitation results in service unavailability that affects legitimate users.
Organizations affected by this vulnerability should prioritize immediate patching to version 4.6.5 or later, which contains the necessary fixes for the resource validation and input handling issues. The mitigation strategy should also include implementing request rate limiting and monitoring for unusual patterns in partitioning operations, as these can serve as early warning indicators of potential exploitation attempts. Security teams should conduct thorough assessments of their phpMyAdmin installations to identify any custom configurations that might exacerbate the vulnerability. Additionally, network-level protections such as web application firewalls can provide additional layers of defense by filtering out suspicious requests that attempt to exploit the partitioning functionality. The incident underscores the importance of regular security updates and proper input validation in database administration tools, as these components are frequently targeted by attackers seeking to compromise database environments.