CVE-2012-4729 in Wing FTP Server
Summary
by MITRE
Wing FTP Server before 4.1.1 allows remote authenticated users to cause a denial of service (daemon crash) via two zip commands.
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Analysis
by VulDB Data Team • 12/19/2021
The CVE-2012-4729 vulnerability affects Wing FTP Server versions prior to 4.1.1, representing a significant denial of service weakness that can be exploited by authenticated remote attackers. This vulnerability specifically targets the server's handling of zip commands, creating a condition where legitimate users can trigger daemon crashes through carefully crafted zip operations. The flaw demonstrates a classic example of improper input validation and resource handling in network services, where the server fails to properly sanitize or process user-supplied zip command parameters. The vulnerability operates at the application layer, leveraging the server's FTP protocol implementation to execute malicious operations that ultimately result in service disruption.
The technical implementation of this vulnerability stems from inadequate error handling within the zip command processing functionality of the FTP server daemon. When authenticated users submit specific zip commands, the server's internal parsing mechanisms fail to properly validate or manage the input parameters, leading to memory corruption or resource exhaustion conditions that cause the daemon to terminate unexpectedly. This represents a CWE-121 vulnerability category related to buffer overflow conditions, though the specific manifestation occurs through command processing rather than direct memory manipulation. The attack vector requires authentication, which means that unauthorized users cannot exploit this directly, but legitimate users with appropriate credentials can cause service disruption. The vulnerability demonstrates poor defensive programming practices where the server does not implement proper exception handling or input sanitization for zip command operations.
The operational impact of CVE-2012-4729 extends beyond simple service interruption, as it can potentially disrupt critical business operations that depend on FTP services for file transfers and data management. Organizations relying on Wing FTP Server for their file sharing infrastructure face the risk of unauthorized service disruption by malicious insiders or compromised legitimate accounts. The daemon crash can result in temporary unavailability of file transfer services, requiring manual intervention to restart the server process and potentially leading to data transfer interruptions. This vulnerability aligns with ATT&CK technique T1499.004 for network denial of service attacks, where adversaries leverage legitimate system functionality to disrupt services. The impact is particularly concerning for environments where FTP services are integral to business operations, as it can affect data synchronization, backup operations, and user access to shared resources.
Mitigation strategies for this vulnerability require immediate patching of Wing FTP Server to version 4.1.1 or later, which contains the necessary fixes for zip command processing. System administrators should implement proper access controls and monitor user activities to detect potential exploitation attempts, as the vulnerability requires authentication to exploit. Network segmentation and monitoring solutions can help identify unusual patterns of zip command usage that might indicate exploitation attempts. Organizations should also consider implementing additional logging mechanisms to track FTP command execution and resource usage patterns. The fix addresses the root cause by implementing proper input validation and error handling for zip commands, preventing the daemon crash conditions that were previously possible. Security teams should conduct regular vulnerability assessments of FTP server implementations to identify similar issues and maintain updated security configurations that align with industry best practices for secure FTP service deployment.