CVE-2006-0328 in Tftpd32
Summary
by MITRE
Format string vulnerability in Tftpd32 2.81 allows remote attackers to cause a denial of service via format string specifiers in a filename in a (1) GET or (2) SEND request.
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Analysis
by VulDB Data Team • 01/20/2025
The vulnerability identified as CVE-2006-0328 represents a critical format string flaw within Tftpd32 version 2.81, a widely used tftp server implementation. This vulnerability exists in the handling of filename parameters within both GET and SEND requests, creating a potential vector for remote attackers to exploit the service. The flaw stems from improper input validation and sanitization of user-supplied data, specifically filename strings that are processed through format string functions without adequate protection against malicious input sequences. The vulnerability affects the core tftp protocol implementation where client requests are processed and interpreted by the server application.
The technical nature of this vulnerability places it squarely within the category of format string vulnerabilities as defined by CWE-134, which occurs when a program uses a user-supplied string as a format string parameter to functions like printf, sprintf, or fprintf. In Tftpd32 2.81, the application fails to properly sanitize filename inputs before using them in format string operations, allowing attackers to inject format specifiers such as %s, %x, or %n that can manipulate the program's execution flow. When these malicious format specifiers are processed, they can cause the application to read from arbitrary memory locations or write data to memory addresses, leading to unpredictable behavior and ultimately resulting in denial of service conditions.
The operational impact of this vulnerability extends beyond simple service disruption, as it represents a fundamental flaw in how the tftp server handles user input validation and memory management. Attackers can leverage this vulnerability to crash the tftp service, making it unavailable to legitimate users who require file transfer capabilities. The remote nature of the attack means that an attacker does not need physical access to the system or elevated privileges to exploit the vulnerability, making it particularly dangerous in networked environments where tftp servers are commonly deployed for network booting, firmware updates, and other administrative functions. The vulnerability affects the availability aspect of the CIA triad, potentially causing significant operational disruption in environments where tftp services are critical for system management.
Mitigation strategies for CVE-2006-0328 should focus on immediate remediation through software updates and patches provided by the vendor, as well as implementing network-level controls to restrict access to tftp services. Organizations should consider disabling tftp services when not actively required, implementing firewall rules to limit access to trusted networks only, and monitoring for suspicious filename patterns in tftp requests. From an ATT&CK perspective, this vulnerability aligns with techniques involving service enumeration and denial of service, where adversaries may use such flaws to compromise system availability and potentially gain further access to network resources. The vulnerability also demonstrates the importance of input validation practices and proper secure coding methodologies, particularly in server applications that process user-provided data. Network administrators should also implement intrusion detection systems to monitor for patterns consistent with format string exploitation attempts, and consider implementing application-level firewalls or proxies to filter potentially malicious requests before they reach the vulnerable tftp service.