CVE-2005-1813 in TFTP Server 2000
Summary
by MITRE
Directory traversal vulnerability in FutureSoft TFTP Server Evaluation Version 1.0.0.1 allows remote attackers to read arbitrary files via a TFTP GET request containing (1) "../" (dot dot slash) or (2) "..\" (dot dot backslash) sequences.
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Analysis
by VulDB Data Team • 07/25/2017
The directory traversal vulnerability identified in FutureSoft TFTP Server Evaluation Version 1.0.0.1 represents a critical security flaw that enables remote attackers to access arbitrary files on the affected system through manipulated TFTP GET requests. This vulnerability specifically targets the server's handling of file path resolution during TFTP operations, where the software fails to properly validate or sanitize input sequences that attempt to navigate outside the intended directory structure. The flaw manifests when attackers submit TFTP GET requests containing either "../" or "..\" sequences, which are standard methods for traversing directory hierarchies in Unix-like and Windows environments respectively. These sequences allow an attacker to move up the directory tree and access files that should remain restricted, potentially exposing sensitive system information, configuration files, or even system binaries.
The technical implementation of this vulnerability stems from insufficient input validation within the TFTP server's file path processing logic. When the server receives a GET request with traversal sequences, it fails to properly canonicalize or sanitize the requested file path before attempting to access the file system. This weakness directly maps to CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal attacks. The vulnerability exists at the application layer where TFTP protocol handling occurs, making it particularly dangerous as TFTP is often used for network booting, firmware updates, and system administration tasks where sensitive data may be accessible. The attack vector is straightforward and requires minimal technical expertise, as it leverages standard path traversal techniques that have been well-documented in cybersecurity literature for decades.
From an operational impact perspective, this vulnerability poses significant risks to network infrastructure security. Attackers can exploit this flaw to access not only user files but potentially system-critical information such as configuration files, log files, or even sensitive data stored in directories accessible to the TFTP service. The vulnerability affects the confidentiality aspect of the CIA triad, as it allows unauthorized information disclosure without requiring authentication or elevated privileges. The impact extends beyond simple file access, as attackers could potentially discover system configurations, user credentials stored in configuration files, or other sensitive data that could be used for further exploitation. This vulnerability also aligns with ATT&CK technique T1213.002, which involves data from information repositories, as it enables access to stored data through manipulation of file access paths. Organizations using this TFTP server version may unknowingly expose their network infrastructure to unauthorized access, particularly in environments where TFTP is used for automated system management tasks.
Mitigation strategies for this vulnerability should focus on immediate remediation through software updates or patches provided by the vendor, as the issue affects the core functionality of the TFTP server implementation. Network administrators should implement firewall rules to restrict TFTP access to trusted networks only, as TFTP is inherently insecure and lacks authentication mechanisms. Additionally, organizations should consider implementing network segmentation to isolate TFTP services from critical systems and limit the potential impact of successful exploitation. The vulnerability demonstrates the importance of input validation and proper path handling in network services, aligning with security best practices outlined in various industry standards including NIST SP 800-125 and ISO/IEC 27001. Organizations should also implement regular vulnerability assessments and penetration testing to identify similar path traversal issues in other network services and applications, as such vulnerabilities remain prevalent in legacy systems and improperly configured network infrastructure components.