CVE-2006-6183 in 3CTftpSvc
Summary
by MITRE
Multiple stack-based buffer overflows in 3Com 3CTftpSvc 2.0.1, and possibly earlier, allow remote attackers to cause a denial of service (crash) or execute arbitrary code via a long mode field (aka transporting mode) in a (1) GET or (2) PUT command.
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Analysis
by VulDB Data Team • 07/11/2019
The vulnerability identified as CVE-2006-6183 represents a critical stack-based buffer overflow flaw affecting 3Com 3CTftpSvc version 2.0.1 and potentially earlier versions. This vulnerability resides within the Trivial File Transfer Protocol (TFTP) service implementation, specifically targeting the handling of the mode field parameter during file transfer operations. The affected service operates as a network daemon that facilitates file transfers between network devices, making it a prime target for exploitation by malicious actors seeking to compromise network infrastructure. The vulnerability stems from inadequate input validation mechanisms that fail to properly sanitize the mode field parameter, which is used to specify the transfer mode such as netascii, octet, or mail. When an attacker sends a malformed TFTP request containing an excessively long mode field, the service processes this input without proper bounds checking, leading to memory corruption that can result in either system crashes or arbitrary code execution. This type of vulnerability falls under the Common Weakness Enumeration category CWE-121, which specifically addresses stack-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent memory locations. The operational impact of this vulnerability extends beyond simple denial of service scenarios, as it can potentially enable remote code execution on affected systems. Attackers exploiting this weakness can craft malicious TFTP requests that overwrite critical memory segments including return addresses, function pointers, or other control data structures, thereby gaining unauthorized control over the affected device. The attack surface is particularly concerning given that TFTP services are commonly deployed in network infrastructure devices, printers, routers, and other embedded systems where administrators may not regularly update firmware or security patches. From an adversarial perspective, this vulnerability aligns with ATT&CK technique T1195.001, which involves the exploitation of vulnerabilities in network protocols to achieve remote code execution. The exploitation process typically involves sending specially crafted GET or PUT commands with oversized mode fields, triggering the buffer overflow condition that allows attackers to manipulate program execution flow. The severity classification of this vulnerability is heightened by its remote exploitability and the potential for privilege escalation, as the TFTP service often runs with elevated system privileges. Network administrators should consider this vulnerability as part of their broader security posture assessment, particularly when dealing with legacy network infrastructure that may still be running unpatched versions of 3Com software. The lack of proper input validation in this context represents a fundamental security flaw that violates core principles of secure coding practices, specifically the principle of least privilege and input sanitization. Organizations maintaining affected systems should immediately implement network segmentation, disable unnecessary TFTP services, and deploy network monitoring solutions to detect anomalous TFTP traffic patterns that may indicate exploitation attempts. The vulnerability also underscores the importance of regular security assessments and patch management programs, as many organizations may continue to operate legacy systems without proper security updates, leaving them exposed to known vulnerabilities that have been documented for years. This particular flaw demonstrates how even seemingly simple network protocols can contain critical security weaknesses that can be leveraged for significant system compromise, emphasizing the need for comprehensive security testing of all network services regardless of their perceived complexity or simplicity.