CVE-2004-0185 in wu-ftpd
Summary
by MITRE
Buffer overflow in the skey_challenge function in ftpd.c for wu-ftp daemon (wu-ftpd) 2.6.2 allows remote attackers to cause a denial of service and possibly execute arbitrary code via a s/key (SKEY) request with a long name.
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Analysis
by VulDB Data Team • 07/13/2025
The vulnerability identified as CVE-2004-0185 represents a critical buffer overflow flaw within the wu-ftp daemon version 2.6.2 that specifically affects the skey_challenge function in the ftpd.c source file. This issue arises from inadequate input validation when processing SKEY authentication requests, creating a scenario where remote attackers can exploit the vulnerability through malformed input data. The vulnerability falls under the Common Weakness Enumeration category CWE-121, which encompasses buffer overflow conditions that occur when insufficient bounds checking allows attackers to overwrite adjacent memory locations. The SKEY authentication mechanism, designed to provide one-time passwords for enhanced security, becomes a vector for exploitation when the system fails to properly validate the length of authentication names.
The technical exploitation of this vulnerability occurs when an attacker sends a specially crafted SKEY request containing an excessively long name parameter to the ftpd service. The skey_challenge function in ftpd.c does not perform adequate bounds checking on the input name length, allowing the attacker to overflow the allocated buffer space and overwrite adjacent memory regions. This buffer overflow can potentially be leveraged to execute arbitrary code on the vulnerable system or cause a denial of service condition that crashes the ftpd daemon. The nature of the overflow means that attackers can overwrite return addresses, function pointers, or other critical memory locations, providing potential paths for privilege escalation or complete system compromise. The vulnerability demonstrates a classic stack-based buffer overflow pattern that aligns with ATT&CK technique T1203, which involves the exploitation of memory corruption vulnerabilities for code execution.
The operational impact of this vulnerability extends beyond simple denial of service, as it represents a significant security risk for systems running the affected wu-ftp daemon version. Organizations utilizing this version of the ftpd service face potential unauthorized access, data breaches, or complete system takeover if exploited successfully. The vulnerability affects the integrity and availability of the file transfer service, which could disrupt business operations and compromise sensitive data transfers. Attackers could leverage this flaw to establish persistent access to systems, particularly in environments where FTP services remain active and unpatched. The exploitation requires minimal privileges and can be automated, making it particularly dangerous for widespread deployment. Security professionals should note that this vulnerability exemplifies the importance of proper input validation and the potential consequences of insufficient bounds checking in network services. The flaw demonstrates how authentication mechanisms, intended to enhance security, can become attack vectors when not properly implemented and validated. Organizations should prioritize patching this vulnerability through updates to the wu-ftp daemon or migration to more secure alternatives, as the potential for remote code execution makes this a critical security concern for any system environment.