CVE-2004-2728 in Connectivity
Summary
by MITRE
Buffer overflow in the FTP server of Hummingbird Connectivity 7.1 and 9.0 allows remote, authenticated users to cause a denial of service (application crash) via a long argument to the XCWD command.
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Analysis
by VulDB Data Team • 07/05/2025
The vulnerability described in CVE-2004-2728 represents a critical buffer overflow flaw within the FTP server component of Hummingbird Connectivity versions 7.1 and 9.0. This issue specifically affects the XCWD command which is used to change the working directory on an FTP server. The vulnerability arises from insufficient input validation and boundary checking when processing user-supplied arguments to this particular command. The flaw exists at the protocol implementation level where the server fails to properly sanitize or limit the length of data received during XCWD operations, creating an exploitable condition that can be triggered by authenticated users.
The technical nature of this vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent memory locations. In the context of FTP servers, this type of vulnerability can be particularly dangerous as it provides a pathway for remote attackers to cause application instability or complete system crashes. The XCWD command specifically is vulnerable because it accepts directory path arguments that are not properly validated for length constraints, allowing an attacker to supply an argument that exceeds the allocated buffer space. When the server attempts to process this oversized argument, the buffer overflow occurs and leads to unpredictable behavior including application termination or system crashes.
The operational impact of this vulnerability extends beyond simple denial of service to potentially compromise the availability of critical file transfer services. Since the vulnerability requires authentication, it limits the attack surface to legitimate users who already possess valid credentials, but this does not diminish its severity. An authenticated attacker with access to the FTP service can exploit this flaw to repeatedly crash the server, effectively denying service to all legitimate users. This makes the vulnerability particularly concerning for environments where FTP services are critical to business operations or where the server hosts sensitive data that requires reliable access. The vulnerability also demonstrates poor defensive programming practices where input validation is not consistently applied across all commands within the FTP protocol implementation.
Mitigation strategies for this vulnerability should focus on both immediate remediation and long-term architectural improvements. The primary solution involves applying the vendor-provided patches or updates that address the buffer overflow in the XCWD command implementation. Organizations should also implement input validation measures that enforce maximum length limits on all FTP command arguments, particularly those that manipulate directory paths or file names. Network segmentation and access controls should be strengthened to limit exposure of vulnerable FTP servers to unnecessary network traffic. From a security monitoring perspective, administrators should implement logging and alerting for abnormal FTP command usage patterns that might indicate exploitation attempts. The vulnerability also highlights the importance of following secure coding practices and conducting regular security assessments of network services, particularly those implementing protocols like FTP that have historically been prone to buffer overflow vulnerabilities. This case study reinforces the need for robust input validation and boundary checking as fundamental security controls that align with the principle of least privilege and defense in depth strategies recommended by security frameworks such as NIST guidelines and the MITRE ATT&CK framework.