CVE-2006-0355 in HomeFtp
Summary
by MITRE
Helmsman Research (aka CoolUtils) HomeFtp 1.1 allows remote attackers to cause an unspecified denial of service via a long USER command combined with a long PASS command and an NLST command.
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Analysis
by VulDB Data Team • 03/19/2017
The vulnerability identified as CVE-2006-0355 affects Helmsman Research's HomeFtp 1.1 FTP server implementation, representing a classic denial of service weakness that exploits improper input handling in network protocol implementations. This vulnerability specifically targets the FTP protocol's authentication and directory listing mechanisms, creating a scenario where malicious actors can disrupt service availability through carefully crafted command sequences. The flaw demonstrates inadequate input validation and buffer management within the FTP server's command processing pipeline, where the system fails to properly handle excessively long command arguments that exceed expected parameter limits.
The technical exploitation mechanism involves a specific sequence of three FTP commands that, when combined, trigger the denial of service condition. Attackers first submit a USER command with an abnormally long username parameter, followed by a PASS command containing an excessively long password, and finally execute an NLST command to list directory contents. This particular combination exploits buffer overflow vulnerabilities or memory allocation issues within the FTP server's command parsing logic, where the system attempts to process these extended parameters without proper bounds checking. The vulnerability operates at the application layer of the network stack, specifically targeting the FTP protocol implementation rather than underlying network infrastructure or operating system components.
The operational impact of this vulnerability extends beyond simple service disruption, as it represents a potential vector for broader network compromise within environments where FTP services are deployed. Organizations utilizing HomeFtp 1.1 may experience complete service unavailability, requiring manual intervention to restart the FTP service and potentially disrupting legitimate user access to file transfer capabilities. This vulnerability aligns with CWE-121, which addresses stack-based buffer overflow conditions, and CWE-122, which covers heap-based buffer overflow scenarios, as the extended command parameters likely trigger memory corruption during processing. The attack pattern follows ATT&CK technique T1499.004, specifically targeting network denial of service through protocol manipulation, where adversaries exploit weaknesses in network service implementations to achieve system disruption.
Mitigation strategies for this vulnerability should prioritize immediate patching of the affected HomeFtp 1.1 implementation, as the vendor has likely released updates addressing the buffer handling issues. Network administrators should implement rate limiting and command length restrictions at network boundaries to prevent exploitation attempts, while also monitoring for unusual command sequences that match the described attack pattern. The solution architecture should incorporate proper input validation mechanisms that enforce maximum parameter lengths for FTP commands, implementing defensive programming practices that prevent buffer overflows. Additionally, organizations should consider implementing intrusion detection systems that can identify and alert on suspicious FTP command sequences, particularly those involving extended USER, PASS, and NLST command parameters that exceed normal operational thresholds.