CVE-2011-5136 in Subscription Manager
Summary
by MITRE
showImg.php in EPractize Labs Subscription Manager, possibly 1.0, allows remote attackers to overwrite arbitrary files via the db parameter.
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Analysis
by VulDB Data Team • 01/25/2018
The vulnerability identified as CVE-2011-5136 resides within the showImg.php component of EPractize Labs Subscription Manager version 1.0, presenting a critical file overwrite flaw that enables remote attackers to manipulate system files through improper input validation. This vulnerability specifically targets the db parameter within the showImg.php script, which fails to properly sanitize user-supplied input, creating an avenue for malicious actors to execute unauthorized file operations. The flaw represents a classic example of insecure direct object reference vulnerability where the application directly uses user-controllable input to determine file paths without adequate validation or access controls.
The technical implementation of this vulnerability allows attackers to craft malicious requests that manipulate the db parameter to target arbitrary files on the server filesystem. When the application processes this parameter, it does not validate whether the specified file path is within acceptable boundaries or if the user has proper authorization to modify the target file. This lack of input sanitization creates a path traversal scenario where attackers can specify file paths that bypass normal access controls and overwrite critical system files, configuration files, or even executable components. The vulnerability stems from insufficient parameter validation and inadequate access control mechanisms within the application's file handling routines.
The operational impact of this vulnerability extends beyond simple file overwrites to encompass potential system compromise and unauthorized access to sensitive data. Remote attackers can leverage this flaw to overwrite critical system files, inject malicious code into existing files, or corrupt application data, potentially leading to complete system takeover. The vulnerability affects the integrity and availability of the subscription management system, as unauthorized modifications can disrupt normal operations and create persistent backdoors for attackers. This flaw particularly impacts organizations relying on the EPractize Labs platform for subscriber management, as it provides attackers with a direct path to compromise the underlying infrastructure and access sensitive subscriber information.
Mitigation strategies for this vulnerability must address both immediate remediation and long-term security improvements. The primary fix involves implementing proper input validation and sanitization for all user-supplied parameters, particularly those used in file operations. Organizations should enforce strict parameter validation that ensures file paths are within expected directories and that users cannot specify absolute paths or traverse directories using special characters. Implementing proper access controls and file permission settings can further limit the damage potential of such vulnerabilities. Security professionals should also consider implementing web application firewalls to detect and block malicious requests targeting this specific vulnerability pattern. This remediation approach aligns with CWE-22 Path Traversal and CWE-73 Improper Neutralization of Special Elements in Output Used by a Downstream Component, and addresses tactics outlined in the ATT&CK framework under T1059 Command and Scripting Interpreter and T1074 Data Staged. The vulnerability underscores the importance of principle of least privilege and proper input validation in preventing unauthorized file operations.