CVE-2005-4882 in Tftpd32
Summary
by MITRE
tftpd in Philippe Jounin Tftpd32 2.74 and earlier, as used in Wyse Simple Imager (WSI) and other products, allows remote attackers to cause a denial of service (daemon crash) via a long filename in a TFTP read (aka RRQ or get) request, a different vulnerability than CVE-2002-2226.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 07/21/2024
The vulnerability identified as CVE-2005-4882 affects the tftpd component within Philippe Jounin Tftpd32 version 2.74 and earlier implementations, specifically impacting Wyse Simple Imager (WSI) and similar products that utilize this TFTP server implementation. This issue represents a denial of service condition where remote attackers can deliberately crash the TFTP daemon by submitting specially crafted requests containing excessively long filenames. The vulnerability operates within the TFTP protocol's read request (RRQ) mechanism, which is fundamental to the file transfer operations that TFTP supports. Unlike CVE-2002-2226 which addressed different aspects of TFTP vulnerability, this particular flaw specifically targets the filename handling within the TFTP read request process, making it a distinct attack vector that requires separate remediation approaches. The TFTP protocol itself is designed for simple file transfers in network environments, typically used for booting diskless workstations or transferring configuration files, and operates on UDP port 69. The implementation in question fails to properly validate or limit the length of filenames submitted in RRQ requests, creating a potential exploitation point for malicious actors seeking to disrupt TFTP services. This vulnerability falls under the category of buffer overflows and input validation issues, which are commonly classified under CWE-121 and CWE-122 within the Common Weakness Enumeration framework, representing weaknesses in the allocation and handling of memory buffers. The attack scenario involves an attacker sending a TFTP read request with an abnormally long filename that exceeds the buffer capacity allocated for filename handling within the Tftp32 implementation. When the daemon attempts to process this oversized filename, it triggers a buffer overflow condition that results in the daemon crashing and terminating its service, thereby causing a denial of service for legitimate users who depend on the TFTP functionality. The operational impact of this vulnerability extends beyond simple service disruption as it can affect critical network operations where TFTP is used for system boot processes, firmware updates, or configuration management. Organizations relying on Wyse Simple Imager or similar products that incorporate this vulnerable TFTP implementation may experience service interruptions during critical maintenance windows or when automated processes depend on reliable TFTP access. The vulnerability demonstrates a clear weakness in the input sanitization process within the TFTP server implementation, where proper bounds checking and validation of user-supplied data fails to prevent maliciously crafted requests from causing system instability. According to ATT&CK framework category T1499, this vulnerability enables adversaries to perform disruption of services, specifically targeting availability through denial of service attacks. The flaw represents a classic example of insufficient input validation that allows attackers to exploit memory handling weaknesses in network services, making it particularly dangerous in environments where TFTP is used for critical infrastructure operations. The attack surface is relatively broad since TFTP servers are commonly deployed in enterprise environments, network device management scenarios, and embedded systems where the vulnerability can be exploited by anyone with network access to the affected system.
The technical exploitation of CVE-2005-4882 requires minimal sophistication and can be executed by any remote attacker who can send UDP packets to the TFTP server port. The attack does not require authentication or special privileges, making it particularly dangerous as it can be leveraged by malicious actors without prior access to the system. The vulnerability demonstrates a fundamental flaw in how the Tftp32 implementation handles user input, specifically failing to implement proper bounds checking for filename lengths within TFTP read requests. This type of vulnerability is categorized under CWE-20, which addresses input validation issues, and CWE-121, which deals with stack-based buffer overflows. The attack mechanism relies on the daemon's inability to properly handle oversized data buffers, causing memory corruption that leads to process termination. The impact of this vulnerability extends to network availability and can potentially disrupt critical operations in environments where TFTP is used for booting systems or transferring essential configuration data. Organizations using affected versions of Tftpd32 should prioritize immediate remediation through patching or upgrading to versions that properly validate filename lengths and implement appropriate buffer management. The vulnerability also highlights the importance of proper software security testing and code review practices, particularly in network services that handle external input. From a defensive perspective, network administrators should consider implementing network segmentation and access controls to limit exposure to this vulnerability, while also monitoring for unusual TFTP traffic patterns that might indicate exploitation attempts. The remediation approach should include updating to patched versions of Tftpd32, implementing network access controls, and potentially disabling TFTP services if they are not essential to operations, as TFTP's lack of authentication and encryption makes it inherently risky for modern network environments. This vulnerability serves as a reminder of the importance of maintaining up-to-date network services and the potential consequences of running legacy software implementations that may contain known security flaws.