CVE-2016-6632 in phpMyAdmin
Summary
by MITRE
An issue was discovered in phpMyAdmin where, under certain conditions, phpMyAdmin may not delete temporary files during the import of ESRI files. 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.
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Analysis
by VulDB Data Team • 10/05/2022
The vulnerability identified as CVE-2016-6632 represents a critical file handling flaw within phpMyAdmin that exposes systems to potential persistent storage attacks through improper temporary file management during ESRI file imports. This issue specifically affects versions of phpMyAdmin that process geospatial data formats, creating a pathway for attackers to exploit the application's failure to properly clean up temporary resources. The vulnerability exists in the import functionality where ESRI shapefiles and related geospatial data formats are processed, leading to accumulation of temporary files that remain on the filesystem after import operations complete. This behavior creates a persistent attack surface that can be leveraged for various malicious activities including storage exhaustion, information disclosure, or privilege escalation attacks.
The technical flaw manifests when phpMyAdmin handles ESRI file imports and fails to properly execute cleanup routines for temporary files created during the parsing and processing stages. These temporary files typically contain intermediate data structures and parsed elements from the ESRI format that should be automatically removed upon successful import completion. However, under certain conditions related to file processing errors, incomplete operations, or specific ESRI file structures, the cleanup mechanism fails, leaving temporary files in the system's temporary directory. This failure creates a resource leak scenario where multiple temporary files accumulate over time, potentially consuming significant disk space and creating opportunities for attackers to gain unauthorized access to sensitive data that may have been temporarily stored during the import process. The vulnerability is classified under CWE-452, which addresses "Improper Resource Shutdown or Release," specifically focusing on the failure to properly dispose of temporary resources.
The operational impact of this vulnerability extends beyond simple resource consumption to create potential security risks that can be exploited in multi-layered attack scenarios. Attackers can leverage the accumulation of temporary files to perform storage exhaustion attacks that may cause denial of service conditions, particularly in environments with limited disk space or strict resource constraints. Additionally, the temporary files may contain sensitive information extracted from the ESRI imports, including database schema details, table structures, or even partial data contents that could be accessed by unauthorized users with filesystem permissions. The vulnerability becomes particularly dangerous when combined with other attack vectors, as the presence of these temporary files can provide attackers with additional information for further exploitation or serve as a foothold for more sophisticated attacks. According to ATT&CK framework, this vulnerability maps to T1499.004 for "Storage Exhaustion Flood" and potentially T1078.004 for "Valid Accounts: Cloud Accounts" when attackers can access temporary files containing authentication or credential information.
Mitigation strategies for CVE-2016-6632 require immediate patching of affected phpMyAdmin installations to versions 4.6.4, 4.4.15.8, or 4.0.10.17, which contain the necessary fixes for proper temporary file cleanup. System administrators should implement regular monitoring of temporary directories to detect and remove any accumulated temporary files that may have resulted from this vulnerability. Additionally, organizations should enforce strict permissions on temporary directories to limit access to authorized users only, and implement automated cleanup processes that periodically remove stale temporary files regardless of the application's cleanup behavior. Network segmentation and access controls should be implemented to restrict the ability of unauthorized users to access the phpMyAdmin application or its temporary storage areas. The vulnerability also highlights the importance of implementing proper input validation and resource management practices in web applications, particularly those handling file imports and processing operations. Organizations should conduct regular security assessments of their phpMyAdmin installations to identify and remediate similar resource management vulnerabilities that could create persistent security risks.