CVE-2006-6673 in WinFtp Server
Summary
by MITRE
WinFtp Server 2.0.2 allows remote attackers to cause a denial of service (crash) via long (1) PASV, (2) LIST, (3) USER, (4) PORT, and possibly other commands.
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Analysis
by VulDB Data Team • 12/21/2024
The vulnerability identified as CVE-2006-6673 affects WinFtp Server version 2.0.2 and represents a classic buffer overflow condition that manifests through FTP command handling. This issue enables remote attackers to trigger a system crash by sending specially crafted long command strings to the FTP server, specifically targeting commands such as PASV, LIST, USER, and PORT. The vulnerability stems from insufficient input validation and boundary checking within the server's command processing logic, where the application fails to properly handle excessively long command parameters that exceed allocated buffer sizes.
The technical flaw manifests as a stack-based buffer overflow occurring when the WinFtp Server processes FTP commands containing overly long parameter strings. When an attacker sends a malformed command with excessive length parameters, the server's parsing routine writes data beyond the bounds of allocated memory buffers, causing memory corruption that leads to application instability and eventual crash. This vulnerability operates at the application layer of the network stack and requires no authentication to exploit, making it particularly dangerous as it can be triggered remotely by any internet-connected user.
The operational impact of this vulnerability extends beyond simple service disruption to potentially enable more sophisticated attack vectors. While the immediate effect is a denial of service condition that crashes the FTP server, the underlying buffer overflow represents a potential entry point for more advanced exploitation techniques. Attackers could potentially leverage this vulnerability to execute arbitrary code on the affected system, especially if the server runs with elevated privileges. The vulnerability affects the availability aspect of the CIA triad, compromising the system's ability to provide continuous service to legitimate users.
Mitigation strategies for this vulnerability should include immediate application of vendor patches or updates to versions that address the buffer overflow conditions in command handling. System administrators should implement network-level filtering to restrict FTP traffic to trusted sources and consider deploying intrusion detection systems that can identify suspicious command sequences. Additionally, implementing proper input validation and boundary checking mechanisms within the FTP server configuration can help prevent similar issues. This vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and could potentially map to ATT&CK technique T1499.004 for denial of service attacks. Organizations should also consider implementing network segmentation to limit the attack surface and ensure that FTP services are not directly exposed to untrusted networks. Regular vulnerability assessments and security audits should be conducted to identify similar buffer overflow conditions in other network services and applications.