CVE-2011-3768 in Phorum
Summary
by MITRE
Phorum 5.2.15a allows remote attackers to obtain sensitive information via a direct request to a .php file, which reveals the installation path in an error message, as demonstrated by css.php and certain other files.
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Analysis
by VulDB Data Team • 02/10/2019
The vulnerability identified as CVE-2011-3768 affects Phorum version 5.2.15a, a widely used open-source web forum software that has been deployed across numerous organizations and websites. This security flaw represents a classic information disclosure vulnerability that exposes sensitive system details to remote attackers. The vulnerability specifically manifests when users make direct requests to certain php files within the application's directory structure, particularly css.php and related components. The flaw demonstrates how improper error handling in web applications can inadvertently reveal critical system information that adversaries can leverage for further exploitation.
The technical mechanism behind this vulnerability involves the application's failure to properly sanitize or handle direct file access requests. When attackers access specific php files such as css.php directly through their web browser or automated tools, the application generates error messages that contain the full installation path of the Phorum software on the server. This path disclosure occurs because the application does not implement proper access controls or input validation before processing requests to these files. The error messages are typically generated when the application attempts to process the request but encounters missing dependencies or invalid parameters that trigger PHP's default error reporting mechanisms. This behavior aligns with CWE-209, which specifically addresses the exposure of error messages that contain sensitive information about the system's configuration, and represents a fundamental weakness in the application's defensive programming practices.
The operational impact of this vulnerability extends beyond simple information disclosure, as it provides attackers with crucial reconnaissance data that can significantly aid in subsequent attack phases. The exposed installation paths can reveal directory structures, server configurations, and potentially other system details that attackers can use to plan more sophisticated attacks. This information disclosure can facilitate path traversal attacks, directory listing enumeration, and other exploitation techniques that require knowledge of the target's file system layout. Additionally, the vulnerability can be leveraged as part of a broader attack chain where the disclosed paths serve as entry points for more serious exploits such as remote code execution or privilege escalation attacks. The exposure of these paths also violates security best practices outlined in the OWASP Top Ten, specifically addressing the risk of information disclosure through improper error handling and inadequate input validation. From an attacker's perspective, this vulnerability aligns with techniques described in the MITRE ATT&CK framework under the information gathering phase, where adversaries collect system information to inform their attack strategy.
The recommended mitigation strategies for CVE-2011-3768 involve implementing proper access controls and error handling mechanisms within the Phorum application. Organizations should ensure that all php files are properly protected against direct access attempts by implementing appropriate authentication checks or access control lists. The application should be configured to suppress detailed error messages in production environments and instead display generic error pages that do not reveal system-specific information. Additionally, developers should implement input validation to prevent direct file access to sensitive components and ensure that all file access requests are properly authenticated and authorized. The vulnerability also underscores the importance of keeping web applications updated with the latest security patches and implementing proper security configurations that align with industry standards such as those recommended by the Center for Internet Security. System administrators should also consider implementing web application firewalls and intrusion detection systems that can monitor for suspicious access patterns and direct file access attempts that may indicate exploitation attempts.