CVE-1999-0256 in WarFTPd
Prediction
by VulDB Data Team • 04/17/2026
A vulnerability was found in Jgaa WarFTPd 1.66. This impacts an unknown function of the component USER/PASS Command. Performing a manipulation results in memory corruption. The attack is possible to be carried out remotely. The exploit has been made public and could be used. Upgrading to version 1.66x4 will fix this issue. It is suggested to upgrade the affected component.
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Analysis
by VulDB Data Team • 04/17/2026
The vulnerability identified as CVE-1999-0256 represents a critical buffer overflow flaw within the war ftp server software that enables remote attackers to execute arbitrary commands on affected systems. This vulnerability resides in the handling of user input within the ftp server implementation, specifically when processing certain command sequences that exceed allocated buffer boundaries. The war ftp server, which was widely deployed during the late 1990s and early 2000s, contained insufficient input validation mechanisms that allowed maliciously crafted data to overwrite adjacent memory locations. The flaw manifests when remote attackers send specially constructed commands that cause the server to write data beyond the bounds of allocated memory buffers, potentially overwriting critical program execution elements such as return addresses or function pointers.
This buffer overflow vulnerability directly maps to CWE-121, which describes heap-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite memory locations. The operational impact of this vulnerability extends beyond simple denial of service, as it provides complete remote code execution capabilities to authenticated or unauthenticated attackers depending on the specific implementation details. Attackers can leverage this flaw to gain full control of the affected ftp server, potentially escalating privileges to the system level and using the compromised server as a launching point for further attacks within the network infrastructure. The vulnerability is particularly dangerous because ftp servers often run with elevated privileges and may provide access to sensitive system resources or user data.
The attack vector for CVE-1999-0256 typically involves connecting to the vulnerable ftp service and sending maliciously crafted commands that trigger the buffer overflow condition. The exploitation process often requires precise control over memory layout and may involve techniques such as stack smashing or return-oriented programming to achieve reliable code execution. Network-based attacks can be executed without requiring prior authentication, making this vulnerability particularly severe in environments where ftp services are exposed to untrusted networks. The vulnerability affects systems running the war ftp server software version 1.64 and earlier, with later versions implementing proper bounds checking and input validation mechanisms. Organizations should note that this vulnerability predates modern security practices and represents a classic example of insufficient input validation that remains relevant to understanding historical security flaws and their remediation approaches.
Mitigation strategies for this vulnerability include immediate patching of the war ftp server software to versions that address the buffer overflow condition through proper input validation and bounds checking. System administrators should also implement network segmentation and access control measures to limit exposure of ftp services to untrusted networks. Additional defensive measures include monitoring network traffic for suspicious ftp command sequences and implementing intrusion detection systems that can identify potential exploitation attempts. The vulnerability demonstrates the importance of secure coding practices and input validation as outlined in the software security principles that were formalized in industry standards following this and similar incidents. Organizations should conduct comprehensive vulnerability assessments to identify other instances of similar flaws within their legacy systems and ensure proper security testing procedures are implemented for all software components.