CVE-2016-9859 in phpMyAdmin
Summary
by MITRE
An issue was discovered in phpMyAdmin. With a crafted request parameter value it is possible to initiate a denial of service attack in import feature. All 4.6.x versions (prior to 4.6.5), 4.4.x versions (prior to 4.4.15.9), and 4.0.x versions (prior to 4.0.10.18) are affected.
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Analysis
by VulDB Data Team • 06/23/2019
The vulnerability identified as CVE-2016-9859 represents a denial of service weakness within phpMyAdmin's import functionality that stems from inadequate input validation mechanisms. This flaw specifically targets the handling of request parameters during database import operations, creating a pathway for malicious actors to disrupt service availability. The affected versions span multiple release branches including 4.6.x prior to 4.6.5, 4.4.x prior to 4.4.15.9, and 4.0.x prior to 4.0.10.18, indicating a widespread impact across the phpMyAdmin ecosystem. The vulnerability manifests when a crafted parameter value is submitted to the import feature, triggering unexpected behavior that can lead to system resource exhaustion or process termination.
The technical implementation of this vulnerability exploits the lack of proper sanitization and validation within the import module's parameter handling. When phpMyAdmin processes an import request with maliciously constructed parameters, the application fails to adequately validate the input before processing, allowing the crafted values to trigger resource-intensive operations or cause the application to enter an unstable state. This weakness falls under the category of insufficient input validation, which is classified as CWE-20 in the Common Weakness Enumeration catalog. The attack vector specifically targets the application's ability to process user-supplied data during import operations, where the system does not properly handle malformed or excessively complex parameter values that could cause the import process to consume excessive computational resources or crash entirely.
From an operational perspective, this vulnerability presents significant risk to database administrators and web application operators who rely on phpMyAdmin for database management tasks. The denial of service condition can render the entire phpMyAdmin interface unavailable, effectively blocking legitimate users from performing critical database operations including imports, exports, and administrative tasks. The impact extends beyond simple service disruption as it can affect database integrity and availability, particularly in environments where phpMyAdmin serves as the primary interface for database administration. The vulnerability is particularly concerning because it affects multiple versions across different release lines, meaning that organizations running any of the affected versions are potentially exposed to this threat. The attack requires minimal sophistication to execute, making it a high-risk vulnerability that can be exploited by both malicious actors and automated tools.
The remediation strategy for CVE-2016-9859 involves immediate upgrading to patched versions of phpMyAdmin where the import parameter validation has been strengthened. Organizations should prioritize updating their phpMyAdmin installations to versions 4.6.5, 4.4.15.9, or 4.0.10.18 respectively, depending on their current version. Beyond the immediate patching, implementing additional security controls such as input validation at the web application firewall level and monitoring for unusual import request patterns can provide defense-in-depth. The vulnerability aligns with several tactics described in the MITRE ATT&CK framework under the initial access and execution phases, where adversaries can leverage such weaknesses to establish persistent access or disrupt services. Security teams should also consider implementing rate limiting and resource monitoring for import operations to detect and mitigate potential exploitation attempts. Organizations should conduct comprehensive vulnerability assessments to identify all instances of affected phpMyAdmin installations and ensure that the patching process does not introduce compatibility issues with existing database management workflows. The vulnerability demonstrates the importance of proper input validation in web applications and serves as a reminder of the critical need for regular security updates and patch management processes.