CVE-2004-2432 in TFTP Server
Summary
by MITRE
WinAgents TFTP Server 3.0 allows remote attackers to cause a denial of service (crash) via a request for a file with a long file name, possibly due to an off-by-one buffer overflow.
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Analysis
by VulDB Data Team • 03/14/2017
The vulnerability identified as CVE-2004-2432 affects WinAgents TFTP Server version 3.0, representing a critical security flaw that enables remote attackers to execute denial of service attacks against affected systems. This issue manifests when the server receives a file transfer request containing an excessively long file name, leading to system instability and potential complete service disruption. The vulnerability resides in the server's handling of file name parameters during TFTP operations, where insufficient input validation allows maliciously crafted requests to trigger system crashes. The specific nature of this flaw suggests a buffer overflow condition that occurs during the processing of file name strings, particularly when the requested file name exceeds predetermined memory allocation limits. This type of vulnerability falls under the category of memory corruption issues that can be exploited to compromise system availability and stability.
The technical implementation of this vulnerability demonstrates an off-by-one buffer overflow condition that occurs when the TFTP server attempts to process file names exceeding normal operational parameters. The flaw arises from inadequate boundary checking during the parsing of file name arguments, where the server allocates memory for file name storage without proper validation of input length. This allows an attacker to send a specially crafted file request containing an excessively long file name string that overflows the allocated buffer space, causing memory corruption and subsequent system crash. The vulnerability's classification aligns with CWE-121, which addresses stack-based buffer overflow conditions, and CWE-122, covering heap-based buffer overflow scenarios. The attack vector operates through standard TFTP network protocols, making it accessible to remote threat actors without requiring privileged access or specialized equipment.
From an operational perspective, this vulnerability presents significant risk to organizations relying on WinAgents TFTP Server for network file operations, as it can be exploited to disrupt critical network services and file transfer operations. The denial of service impact extends beyond simple service interruption, potentially affecting network infrastructure reliability and business continuity operations that depend on stable file transfer capabilities. Attackers can leverage this vulnerability to repeatedly crash the TFTP server, creating persistent availability issues that may require manual intervention to restore normal operations. The vulnerability's remote exploitability means that threat actors can target affected systems from anywhere on the network, making it particularly dangerous in enterprise environments where TFTP services are commonly deployed for various network management functions. This vulnerability also aligns with ATT&CK technique T1499.004, which covers network denial of service attacks through exploitation of service vulnerabilities.
Mitigation strategies for CVE-2004-2432 should prioritize immediate deployment of vendor patches or updates that address the buffer overflow condition in WinAgents TFTP Server 3.0. Organizations should implement network segmentation to isolate TFTP services from critical network segments and deploy network monitoring solutions to detect unusual file transfer patterns that may indicate exploitation attempts. Input validation controls should be implemented to limit file name lengths and prevent malformed requests from reaching the server. Additionally, organizations should consider migrating to more modern TFTP implementations or alternative file transfer protocols that have better security track records and more robust input handling mechanisms. Security administrators should also establish regular vulnerability assessment procedures to identify and remediate similar issues in other network services, as this vulnerability demonstrates the importance of proper buffer management and input validation in network applications. The remediation approach should also include network access controls to limit TFTP service exposure and implement logging mechanisms to track file transfer activities for security monitoring purposes.