CVE-2015-3640 in phpMyBackupPro
Summary
by MITRE
phpMyBackupPro 2.5 and earlier does not properly escape the "." character in request parameters, which allows remote authenticated users with knowledge of a web-accessible and web-writeable directory on the target system to inject and execute arbitrary PHP scripts by injecting scripts via the path, filename, and dirs parameters to scheduled.php, and making requests to injected scripts.
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Analysis
by VulDB Data Team • 01/06/2021
The vulnerability identified as CVE-2015-3640 affects phpMyBackupPro version 2.5 and earlier, representing a critical security flaw in the backup and restoration functionality of this web-based database management tool. This issue stems from improper input validation and sanitization within the application's parameter handling mechanisms, specifically concerning the "." character in request parameters. The vulnerability exists within the scheduled.php script which processes backup scheduling operations and allows for arbitrary code execution when exploited by authenticated users who possess knowledge of accessible web directories.
The technical flaw manifests in the application's failure to properly escape or sanitize the "." character when processing path, filename, and dirs parameters. This inadequate input validation creates a path traversal and code injection vulnerability that can be exploited through carefully crafted requests. When authenticated users submit malicious parameters containing unescaped dots, the application fails to properly validate these inputs before incorporating them into file system operations or script execution contexts. The vulnerability is particularly dangerous because it requires only authenticated access and knowledge of web-accessible directories, making it exploitable by users who already have legitimate access to the system.
The operational impact of this vulnerability is severe as it allows authenticated attackers to execute arbitrary PHP code on the target system with the privileges of the web server process. This capability enables attackers to perform a wide range of malicious activities including data exfiltration, system compromise, privilege escalation, and persistence mechanisms. The vulnerability specifically targets the scheduled backup functionality, which means that attackers can inject malicious scripts into backup processes and then execute them at scheduled intervals. This creates a persistent threat vector that can operate without continuous user interaction, making detection and remediation more challenging.
From a cybersecurity perspective, this vulnerability aligns with CWE-74 and CWE-94 categories, representing weaknesses in input validation and code injection. The attack pattern follows the MITRE ATT&CK framework's techniques for command and control through web shell deployment and privilege escalation. The vulnerability is particularly concerning because it combines multiple attack vectors including path traversal, arbitrary code execution, and persistence mechanisms. The requirement for only authenticated access makes this vulnerability particularly dangerous in environments where user access controls are not properly enforced, as legitimate users could potentially exploit this flaw to gain unauthorized access to system resources and data.
Mitigation strategies should include immediate patching of phpMyBackupPro to version 2.6 or later, which addresses the input validation issues. Additionally, administrators should implement proper input sanitization and validation at all entry points, particularly for file path and directory parameters. Network segmentation and web application firewalls can provide additional defense-in-depth measures to detect and prevent exploitation attempts. Regular security audits should verify that all web-accessible directories have proper access controls and that the application's backup functionality is properly configured to prevent unauthorized code injection. The vulnerability also underscores the importance of implementing principle of least privilege access controls and regular security assessments of web applications to identify and remediate similar input validation flaws.