CVE-2003-0772 in WS_FTP Server
Summary
by MITRE
Multiple buffer overflows in WS_FTP 3 and 4 allow remote authenticated users to cause a denial of service and possibly execute arbitrary code via long (1) APPE (append) or (2) STAT (status) arguments.
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Analysis
by VulDB Data Team • 07/24/2025
The vulnerability identified as CVE-2003-0772 affects WS_FTP versions 3 and 4, representing a critical security flaw that enables authenticated remote attackers to exploit buffer overflows within the file transfer protocol implementation. This vulnerability manifests through two distinct attack vectors involving the APPE (append) and STAT (status) commands, which are fundamental components of the ftp protocol. The flaw stems from insufficient input validation and inadequate buffer size management within the application's command processing logic, creating opportunities for malicious input to overwrite adjacent memory regions.
The technical implementation of this vulnerability involves the application's failure to properly sanitize user-supplied arguments before processing them through the ftp protocol commands. When an authenticated user submits excessively long arguments to either the APPE or STAT commands, the application's internal buffers cannot accommodate the input data, resulting in memory corruption. This buffer overflow condition can be leveraged to execute arbitrary code on the target system or cause a denial of service through application crashes. The vulnerability is classified under CWE-121 as a stack-based buffer overflow, which occurs when more data is written to a buffer than it can hold, causing adjacent memory to be overwritten.
From an operational perspective, this vulnerability presents significant risks to organizations relying on WS_FTP versions 3 and 4 for file transfer operations. The authenticated nature of the exploit means that attackers must first establish valid credentials, but this requirement does not significantly diminish the threat level given that many organizations maintain default accounts or weak credential practices. The potential for remote code execution makes this vulnerability particularly dangerous as it could allow attackers to establish persistent access, escalate privileges, and move laterally within network environments. The denial of service component further compounds the impact by potentially disrupting legitimate business operations and file transfer capabilities.
The attack surface for this vulnerability aligns with the ATT&CK framework's execution and privilege escalation tactics, as successful exploitation could enable adversaries to execute malicious code and potentially gain higher privileges. Organizations should implement immediate mitigations including applying vendor patches, disabling unnecessary ftp commands, implementing network segmentation, and monitoring for suspicious ftp activity. The vulnerability demonstrates the importance of proper input validation and memory management practices in network applications, highlighting how even well-established ftp implementations can contain critical security flaws. Security teams should conduct comprehensive assessments of all ftp implementations and ensure proper configuration management to prevent exploitation of similar buffer overflow vulnerabilities in other applications.
The remediation approach should prioritize immediate patching of affected WS_FTP versions, followed by implementation of network-based controls such as firewall rules limiting ftp access and intrusion detection system monitoring for long argument patterns. Additionally, organizations should establish robust credential management practices and conduct regular security assessments to identify similar vulnerabilities in legacy applications. The vulnerability underscores the critical need for maintaining up-to-date software versions and implementing proper security controls throughout the enterprise infrastructure to prevent exploitation of known vulnerabilities.