CVE-2008-0405 in HTTP File Server
Summary
by MITRE
Multiple directory traversal vulnerabilities in HTTP File Server (HFS) before 2.2c, when account names are used as log filenames, allow remote attackers to create arbitrary (1) files and (2) directories via a .. (dot dot) in an account name, when requesting the / URI; and (3) append arbitrary data to a file via a .. (dot dot) in an account name, when requesting a URI composed of a "/?%0a" sequence followed by the data.
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Analysis
by VulDB Data Team • 11/04/2017
The vulnerability identified as CVE-2008-0405 represents a critical directory traversal flaw in HTTP File Server (HFS) versions prior to 2.2c, specifically affecting systems that utilize account names as log filenames. This vulnerability stems from inadequate input validation and path resolution mechanisms within the server's handling of account identifiers, creating exploitable conditions that can be leveraged by remote attackers to manipulate the file system in unauthorized ways. The flaw manifests when the server processes account names that contain directory traversal sequences, allowing malicious actors to bypass normal file system access controls and execute arbitrary file operations.
The technical exploitation of this vulnerability occurs through carefully crafted account names containing .. (dot dot) sequences that traverse up the directory hierarchy. When attackers submit account names with these traversal sequences to the / URI endpoint, they can create arbitrary files and directories in locations outside the intended web root or user access boundaries. Additionally, the vulnerability extends to file appending operations where attackers can inject data into existing files by constructing URIs with the pattern "/?%0a" followed by their target data, effectively enabling them to modify log files or other sensitive system files. This dual capability of creating new file system objects and appending data to existing files represents a comprehensive compromise of the server's file system integrity and access controls.
The operational impact of this vulnerability is severe and multifaceted, as it enables attackers to potentially gain persistent access to the server's file system, modify critical application files, inject malicious content, and compromise the confidentiality and integrity of stored data. The vulnerability's ability to create arbitrary files and directories allows for the establishment of backdoors or the deployment of malicious payloads, while the file appending capability enables attackers to corrupt log files or inject malicious code that could be executed by the server or other applications. This vulnerability directly violates fundamental security principles of least privilege and proper input validation, creating an attack surface that can be leveraged for further compromise of the affected system or network.
The vulnerability aligns with CWE-22 Directory Traversal and CWE-77 Path Traversal, both of which classify this as a fundamental flaw in path resolution and input sanitization within web applications and servers. From an ATT&CK perspective, this vulnerability maps to techniques involving directory traversal and file system manipulation, enabling adversaries to establish persistence, escalate privileges, and maintain access to compromised systems. The attack vector is particularly concerning as it requires no authentication for initial exploitation, making it a significant risk for publicly accessible HFS installations. Organizations should immediately implement mitigations including upgrading to HFS version 2.2c or later, implementing proper input validation for account names, and restricting access to the affected server through network segmentation and firewall rules. Additionally, regular security assessments and monitoring of log files for unusual patterns or unauthorized file system modifications should be implemented to detect potential exploitation attempts and maintain overall system security posture.