CVE-2015-3638 in phpMyBackupPro
Summary
by MITRE
phpMyBackupPro before 2.5 does not validate integer input, which allows remote authenticated users to execute arbitrary PHP code by injecting scripts via the path, filename, and period parameters to scheduled.php, and making requests to injected scripts, or by injecting PHP into a PHP configuration variable via a PHP variable variable.
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Analysis
by VulDB Data Team • 01/06/2021
The vulnerability described in CVE-2015-3638 affects phpMyBackupPro versions prior to 2.5 and represents a critical security flaw that enables remote authenticated attackers to execute arbitrary PHP code. This vulnerability stems from inadequate input validation within the application's handling of integer parameters, creating a pathway for malicious code injection that can compromise the entire system. The flaw specifically manifests in the scheduled.php script where attackers can manipulate the path, filename, and period parameters to inject malicious scripts that will be executed with the privileges of the web application. The vulnerability operates under the principle of code injection, where unvalidated user input is directly incorporated into executable code without proper sanitization or validation mechanisms. This type of vulnerability falls under CWE-94, which encompasses "Improper Control of Generation of Code ('Code Injection')" and specifically relates to the improper handling of user-supplied data that gets executed as code. The attack vector requires an authenticated user, meaning that an attacker must first gain valid credentials to the phpMyBackupPro application before exploiting this vulnerability, which reduces the attack surface but does not eliminate the severity of the potential impact. The vulnerability's exploitation involves two primary methods: the first approach utilizes the path, filename, and period parameters in scheduled.php to inject scripts that can be executed by the application, while the second method targets PHP configuration variables through the use of PHP variable variables, which creates an additional attack surface by allowing manipulation of PHP's internal variable handling mechanisms.
The operational impact of CVE-2015-3638 extends beyond simple code execution, as it can lead to complete system compromise and unauthorized access to sensitive data stored within the database environment. When successfully exploited, this vulnerability allows attackers to execute arbitrary commands on the server, potentially leading to data theft, system modification, or the establishment of persistent backdoors. The remote authenticated nature of the attack means that an attacker can leverage this vulnerability from any location where they have valid login credentials, making it particularly dangerous in environments where administrative access is granted to multiple users. The attack can result in the complete compromise of the web server hosting phpMyBackupPro, as the executed code runs with the privileges of the web application user, which typically has access to database connections and file system operations. The vulnerability's potential for data exfiltration is significant, as attackers can manipulate database backups, access sensitive configuration files, and potentially escalate privileges to gain root or administrator access to the underlying operating system. Organizations using vulnerable versions of phpMyBackupPro face a substantial risk of unauthorized data access, system integrity compromise, and potential regulatory violations if sensitive information is exposed or altered through this vulnerability.
Mitigation strategies for CVE-2015-3638 primarily focus on updating to the patched version of phpMyBackupPro 2.5 or later, which includes proper input validation and sanitization mechanisms to prevent the injection of malicious code. System administrators should immediately implement this update as a priority action to address the vulnerability, as there are no effective workarounds or patches available for older versions. The implementation of proper input validation should include strict sanitization of all user-supplied data, particularly integer parameters and file path inputs, to ensure that malicious code cannot be injected into the application's execution flow. Organizations should also consider implementing additional security controls such as web application firewalls that can detect and block suspicious parameter values, and network segmentation to limit the potential impact of successful exploitation. The vulnerability's classification under ATT&CK technique T1059.007 "Command and Scripting Interpreter: PowerShell" and T1059.006 "Command and Scripting Interpreter: Unix Shell" indicates that the attack may involve command execution through shell interfaces, making it essential for organizations to monitor for unusual command execution patterns. Regular security assessments and vulnerability scanning should be conducted to identify other potential injection points within the application, as this vulnerability demonstrates a pattern of insufficient input validation that may exist in other areas of the codebase. The remediation process should also include reviewing user access controls and implementing principle of least privilege to ensure that only necessary users have administrative access to the phpMyBackupPro application, thereby limiting the potential impact of credential compromise.