CVE-2003-1368 in FTP Client
Summary
by MITRE
Buffer overflow in the 32bit FTP client 9.49.1 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 described in CVE-2003-1368 represents a classic buffer overflow flaw affecting the 32-bit FTP client version 9.49.1. This issue stems from inadequate input validation within the client software's handling of FTP server responses, specifically the server banner message that is transmitted during the initial connection phase. The flaw occurs when the client receives an FTP server banner that exceeds the allocated buffer size, causing the program to overwrite adjacent memory regions. This type of vulnerability falls under the Common Weakness Enumeration category CWE-121, which specifically addresses stack-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite stack data. The vulnerability exists in the client-side implementation of the File Transfer Protocol, which is a fundamental networking protocol widely used for transferring files between computers.
The technical exploitation of this buffer overflow vulnerability enables remote attackers to either crash the FTP client application or potentially execute arbitrary code with the privileges of the user running the client. When an attacker crafts a malicious FTP server response containing an oversized banner message, the client's buffer handling code fails to properly validate the input length before copying data into its internal buffers. This results in memory corruption that can be leveraged to redirect program execution flow, allowing for code injection attacks. The vulnerability demonstrates characteristics consistent with the ATT&CK technique T1203 - Exploitation for Client Execution, where attackers exploit weaknesses in client applications to gain unauthorized code execution capabilities. The impact extends beyond simple denial of service since the buffer overflow could potentially be weaponized to establish persistent access to systems running the vulnerable client software.
From an operational standpoint, this vulnerability presents significant risks to organizations that rely on FTP clients for file transfers, particularly in environments where network traffic cannot be fully controlled or monitored. The vulnerability is especially concerning because it can be exploited remotely without requiring any special privileges or authentication from the attacker's perspective. Systems running the affected FTP client version 9.49.1 are susceptible to compromise regardless of their network location, making this a critical security concern for enterprise environments. The vulnerability also impacts the availability of services since the client crash can disrupt legitimate file transfer operations. Organizations may experience service interruptions, data transfer failures, and potential system compromise that could lead to broader security incidents. The attack surface is further expanded by the fact that many users may unknowingly connect to malicious FTP servers, making this vulnerability particularly dangerous in environments with limited network security controls or where users have unrestricted access to external networks.
Mitigation strategies for CVE-2003-1368 should focus on immediate software updates and patches provided by the vendor, which would address the buffer overflow condition through proper input validation and bounds checking. System administrators should prioritize updating all instances of the affected FTP client software to versions that include memory safety improvements and enhanced input validation mechanisms. Network segmentation and firewall rules can help limit exposure by preventing unauthorized FTP server access, while network monitoring solutions should be configured to detect unusual FTP traffic patterns that might indicate exploitation attempts. The implementation of secure coding practices, including the use of safe string handling functions and buffer size validation, should be enforced throughout the organization's software development lifecycle to prevent similar vulnerabilities from being introduced in future applications. Additionally, security awareness training for users can help reduce the risk of inadvertently connecting to malicious FTP servers that might be used to exploit this vulnerability. Organizations should also consider implementing network access controls that limit FTP client access to trusted servers and establish logging procedures to detect potential exploitation attempts.