CVE-2004-1883 in WS FTP Server
Summary
by MITRE
Multiple buffer overflows in Ipswitch WS_FTP Server 4.0.2 (1) allow remote authenticated users to execute arbitrary code by causing a large error string to be generated by the ALLO handler, or (2) may allow remote FTP administrators to execute arbitrary code by causing a long hostname or username to be inserted into a reply to a STAT command while a file is being transferred.
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Analysis
by VulDB Data Team • 09/12/2025
The vulnerability identified as CVE-2004-1883 represents a critical security flaw in Ipswitch WS_FTP Server version 4.0.2 that exposes multiple buffer overflow conditions capable of enabling remote code execution. This vulnerability affects the server's handling of specific command inputs and demonstrates the dangerous consequences of improper input validation in network services. The flaw exists within the server's response mechanisms to file transfer operations and administrative commands, creating pathways for malicious actors to exploit the system through carefully crafted inputs.
The technical implementation of this vulnerability manifests in two distinct attack vectors that leverage buffer overflow conditions within the server's processing logic. The first vector occurs when the ALLO command handler processes large error strings that exceed allocated buffer boundaries, causing memory corruption that can be leveraged to execute arbitrary code. The second vector involves the STAT command response handling during file transfers, where excessively long hostnames or usernames are inserted into reply messages without proper bounds checking, resulting in similar memory corruption vulnerabilities. Both attack paths demonstrate the fundamental weakness in input sanitization and memory management within the server's protocol implementation.
From an operational perspective, this vulnerability presents significant risk to organizations relying on the affected WS_FTP Server version, as it allows authenticated users to escalate privileges and execute malicious code remotely. The attack requires only basic FTP authentication credentials to exploit, making it particularly dangerous in environments where FTP administrative access is granted to multiple users. The potential impact includes complete system compromise, data exfiltration, and lateral movement within network infrastructure. Security professionals must consider that these buffer overflows can be exploited by attackers with minimal privileges to gain elevated system access, potentially leading to full network compromise.
The vulnerability aligns with CWE-121, which addresses stack-based buffer overflow conditions, and CWE-122, covering heap-based buffer overflow scenarios, demonstrating the comprehensive nature of the memory corruption issues present. From an ATT&CK framework perspective, this vulnerability maps to T1078 for valid accounts and T1059 for command and scripting interpreter, as attackers can leverage authenticated sessions to execute code and potentially establish persistence. The exploitation process follows T1203 for exploitation for privilege escalation, where legitimate user credentials are used to gain elevated system privileges. Organizations should implement immediate patching measures to address this vulnerability, as the affected version lacks modern security mitigations such as stack canaries, address space layout randomization, or non-executable stack protections that would otherwise prevent successful exploitation.
Mitigation strategies should include immediate deployment of vendor patches or updates to the WS_FTP Server software, followed by network segmentation to limit access to FTP services and implementation of intrusion detection systems to monitor for exploitation attempts. Security teams should also conduct comprehensive vulnerability assessments to identify any other instances of the affected software within their infrastructure and establish monitoring protocols for suspicious FTP activity patterns that may indicate exploitation attempts. The vulnerability serves as a reminder of the critical importance of input validation and proper memory management in network services, particularly those handling user-provided data in protocol implementations.