CVE-2009-2546 in Advanced Electron Forum
Summary
by MITRE
Directory traversal vulnerability in Advanced Electron Forum (AEF) 1.x allows remote attackers to determine the existence of arbitrary files via the avatargalfile parameter when changing an avatar, which leaks the existence of the file in an error message. NOTE: the provenance of this information is unknown; the details are obtained solely from third party information.
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Analysis
by VulDB Data Team • 12/18/2017
The vulnerability identified as CVE-2009-2546 represents a directory traversal flaw within Advanced Electron Forum version 1.x that exposes sensitive system information through error messages. This type of vulnerability falls under the category of information disclosure, where attackers can exploit improper input validation to gain knowledge about the underlying file system structure. The issue specifically manifests when users attempt to change their avatar through the avatargalfile parameter, which processes user-supplied file paths without adequate sanitization or validation mechanisms.
The technical exploitation of this vulnerability occurs through manipulation of the avatargalfile parameter, which accepts user input for avatar file selection. When an attacker provides a malicious file path containing directory traversal sequences such as ../ or ..\, the application fails to properly validate or sanitize this input before processing. This lack of input validation creates a scenario where the application attempts to access files outside the intended directory structure, resulting in error messages that inadvertently reveal information about the existence of arbitrary files on the server. The vulnerability is classified as a directory traversal attack pattern that aligns with CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal.
From an operational perspective, this vulnerability poses significant risks to the security posture of affected systems. The information leakage through error messages provides attackers with valuable reconnaissance data about the server's file system layout, including the existence of sensitive files, configuration files, or system directories. This reconnaissance capability enables attackers to plan more sophisticated attacks targeting specific system components or sensitive data repositories. The vulnerability's remote nature means that attackers do not require local system access or credentials to exploit it, making it particularly dangerous for publicly accessible web applications. The error message leakage mechanism creates a passive information disclosure channel that can be exploited by automated tools to systematically enumerate files and directories on the target system.
The impact of this vulnerability extends beyond simple information disclosure, as it can serve as a foundational step for more complex attack vectors. Attackers can use the leaked information to identify potential targets for further exploitation, such as finding backup files, configuration files containing database credentials, or system files that might contain additional vulnerabilities. The vulnerability's classification under the ATT&CK framework would place it within the reconnaissance phase, specifically under techniques related to credential access and enumeration. This type of vulnerability is particularly concerning in environments where multiple applications share the same server infrastructure, as successful exploitation could potentially reveal information about other applications or services running on the same host.
Effective mitigation strategies for CVE-2009-2546 require immediate implementation of proper input validation and sanitization mechanisms. The most critical remediation involves implementing strict parameter validation for the avatargalfile input, ensuring that all user-supplied paths are properly sanitized and restricted to predefined safe directories. This approach aligns with the principle of least privilege and input validation best practices recommended by security standards such as those outlined in the OWASP Top Ten. Organizations should also implement proper error handling mechanisms that prevent sensitive system information from being exposed in error messages, ensuring that all error responses are generic and do not reveal internal system details. Additionally, regular security audits and code reviews should be conducted to identify and remediate similar vulnerabilities in other application components. The implementation of web application firewalls and input filtering mechanisms can provide additional layers of protection against directory traversal attempts. Given the age of this vulnerability and the specific version affected, upgrading to a patched version of Advanced Electron Forum represents the most effective long-term solution to prevent exploitation of this and similar directory traversal vulnerabilities.