CVE-2006-0356 in Home Ftp Server
Summary
by MITRE
Ari Pikivirta Home Ftp Server 1.0.7 allows remote attackers to cause an unspecified denial of service via a long USER command combined with a long PASS command.
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Analysis
by VulDB Data Team • 03/19/2017
The Ari Pikivirta Home FTP Server version 1.0.7 presents a significant denial of service vulnerability that can be exploited by remote attackers through carefully crafted FTP command sequences. This vulnerability specifically manifests when an attacker submits an excessively long USER command followed by an equally prolonged PASS command to the FTP server. The flaw resides in the server's inadequate input validation and buffer handling mechanisms, which fail to properly process or limit the length of authentication command parameters. The server's failure to implement proper bounds checking on user input creates an exploitable condition where malformed command sequences can cause the service to become unresponsive or crash entirely.
This vulnerability operates at the application layer of the network stack and represents a classic buffer overflow scenario that has been documented under the Common Weakness Enumeration framework as CWE-121. The attack vector requires minimal privileges since it targets the authentication process itself, making it particularly dangerous as it can be exploited by any remote user without requiring prior access credentials. The combination of long USER and PASS commands creates a cascading effect where the server's memory management routines become overwhelmed during the authentication processing phase, leading to service disruption. The unspecified nature of the denial of service indicates that the exact mechanism of service failure may vary but consistently results in the server becoming unavailable to legitimate users.
The operational impact of this vulnerability extends beyond simple service interruption, as it can be leveraged for broader network disruption within environments where FTP services are critical for business operations. When exploited successfully, the vulnerability can cause the FTP server to crash or become unresponsive for extended periods, effectively denying legitimate users access to file transfer capabilities. This type of denial of service attack can be particularly damaging in scenarios where the FTP server serves as a critical component in data backup, file distribution, or application deployment processes. The vulnerability's exploitation aligns with techniques described in the MITRE ATT&CK framework under the T1499 category for network denial of service attacks, specifically targeting the availability aspect of the CIA triad.
Mitigation strategies for this vulnerability should focus on implementing proper input validation and buffer size limitations within the FTP server's authentication handling routines. System administrators should immediately upgrade to patched versions of the Ari Pikivirta Home FTP Server or implement network-level restrictions that limit the length of commands accepted by the server. Network segmentation and access control measures can help reduce the attack surface by limiting direct exposure of the vulnerable FTP service to untrusted networks. Additionally, implementing intrusion detection systems that monitor for unusual command sequences or excessive input lengths can provide early warning of potential exploitation attempts. The vulnerability serves as a reminder of the critical importance of input validation and proper memory management in network services, particularly those handling authentication processes where malformed inputs can lead to complete service disruption.