CVE-2003-1369 in ByteCatcher FTP
Summary
by MITRE
Buffer overflow in ByteCatcher FTP client 1.04b allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code via a long FTP server banner.
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Analysis
by VulDB Data Team • 01/26/2025
The vulnerability identified as CVE-2003-1369 represents a critical buffer overflow flaw within the ByteCatcher FTP client version 1.04b that exposes users to both denial of service conditions and potential remote code execution risks. This issue stems from inadequate input validation mechanisms within the client's handling of FTP server responses, specifically when processing the initial server banner message that is automatically sent upon connection establishment. The flaw manifests when the FTP client receives a server response exceeding the allocated buffer space, causing memory corruption that can lead to application instability or complete crash. The vulnerability operates at the application layer of the network stack, affecting the client-side software that establishes connections to FTP servers, making it particularly dangerous as it can be exploited through legitimate network interactions without requiring special privileges or authentication.
The technical implementation of this buffer overflow vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent memory locations. In the context of the ByteCatcher FTP client, the vulnerability occurs during the initial connection phase when the client processes the server banner string, which typically contains server identification information including version numbers and operational details. When an attacker crafts a malicious FTP server response containing an excessively long banner string, the client's inadequate memory management causes the buffer to overflow, potentially overwriting critical program execution data such as return addresses or function pointers. This memory corruption can result in unpredictable program behavior, application crashes, or in more sophisticated attack scenarios, allow attackers to inject and execute arbitrary code within the client's execution context, effectively compromising the user's system.
The operational impact of this vulnerability extends beyond simple service disruption to encompass potential system compromise and data exposure risks. Users employing the affected ByteCatcher FTP client version face significant security risks when connecting to untrusted FTP servers, as the vulnerability can be exploited through routine network operations without user intervention or explicit action. The attack vector is particularly concerning because it requires no authentication credentials or special privileges from the attacker, making it accessible to anyone capable of controlling an FTP server that the victim might connect to through normal network operations. The vulnerability's potential for remote code execution places the entire system at risk, as successful exploitation could allow attackers to gain full control over the user's machine, install malware, access sensitive data, or establish persistent backdoors. This makes the vulnerability particularly dangerous in enterprise environments where users might inadvertently connect to compromised servers or when the client is used in automated processes.
Mitigation strategies for CVE-2003-1369 must address both immediate protection needs and long-term security improvements within the affected software ecosystem. Organizations should immediately upgrade to patched versions of the ByteCatcher FTP client or migrate to more secure alternative FTP clients that have properly implemented input validation and memory management controls. The vulnerability demonstrates the importance of implementing proper bounds checking and input validation mechanisms as outlined in the software security principles of the OWASP Top Ten and the CERT/CC secure coding guidelines. Security administrators should also consider network segmentation and monitoring to detect suspicious FTP server responses that might indicate exploitation attempts. The remediation process should include comprehensive security testing of all FTP client implementations to identify similar buffer overflow vulnerabilities, particularly focusing on areas where network responses are processed without adequate size validation. Additionally, users should be educated about the risks of connecting to untrusted FTP servers and the importance of maintaining updated software versions, as this vulnerability highlights the critical need for regular security updates and patch management procedures in preventing exploitation of known vulnerabilities.