CVE-2009-4960 in Lanai-core
Summary
by MITRE
Directory traversal vulnerability in modules/backup/download.php in Lanai Core 0.6 allows remote attackers to read arbitrary files via a .. (dot dot) in the f parameter.
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Analysis
by VulDB Data Team • 02/06/2019
The vulnerability identified as CVE-2009-4960 represents a critical directory traversal flaw within the Lanai Core 0.6 web application framework, specifically affecting the backup module's download functionality. This weakness resides in the modules/backup/download.php script where user input containing directory traversal sequences is not properly validated or sanitized before being processed. The vulnerability manifests when attackers manipulate the f parameter by injecting .. (dot dot) sequences, which allows them to navigate beyond the intended directory structure and access arbitrary files on the server filesystem. This type of vulnerability falls under the category of CWE-22 - Improper Limitation of a Pathname to a Restricted Directory, which is a fundamental security flaw that enables unauthorized access to sensitive system resources.
The technical exploitation of this vulnerability occurs through a straightforward manipulation of the file parameter in the backup download module. When a remote attacker submits a malicious value containing directory traversal sequences such as ../../etc/passwd or ../../../windows/system32/drivers/etc/hosts, the application fails to properly validate these inputs against a whitelist of acceptable paths. The lack of proper input sanitization and path validation creates an opportunity for attackers to browse the server's file system and potentially retrieve sensitive information including configuration files, database credentials, application source code, and system files. This vulnerability directly impacts the principle of least privilege and can lead to complete system compromise if sensitive files are accessible through the backup module.
The operational impact of CVE-2009-4960 extends beyond simple file disclosure, as it can enable attackers to escalate their privileges and gain deeper access to the underlying system infrastructure. Attackers can leverage this vulnerability to obtain database connection strings, application configuration files containing encryption keys, and other sensitive data that could be used for further exploitation. The vulnerability also aligns with several techniques described in the MITRE ATT&CK framework under the T1083 - File and Directory Discovery tactic, where adversaries systematically explore file systems to identify valuable targets. Additionally, this vulnerability can be chained with other exploits to perform more sophisticated attacks such as remote code execution through the inclusion of malicious files or to establish persistent access through the compromise of system configuration files.
Mitigation strategies for this vulnerability should focus on implementing robust input validation and proper path sanitization techniques. Organizations should implement a whitelist-based approach for file access, where only explicitly defined and safe file paths are permitted for retrieval through the backup module. The application should employ proper directory traversal prevention mechanisms such as canonicalizing file paths and ensuring that user-supplied input cannot contain sequences that would allow navigation outside of intended directories. Security patches should be applied immediately to address this vulnerability, and the system should be configured to restrict file access permissions to prevent unauthorized reading of critical system files. Network segmentation and access controls should also be implemented to limit exposure of the backup module to untrusted users, while regular security audits and input validation testing should be conducted to prevent similar vulnerabilities from being introduced in future development cycles.