CVE-2012-10023 in FTP Server
Summary
by MITRE • 08/05/2025
A stack-based buffer overflow vulnerability exists in FreeFloat FTP Server version 1.0.0. The server fails to properly validate input passed to the USER command, allowing remote attackers to overwrite memory and potentially execute arbitrary code. The flaw is triggered by sending an overly long username string, which overflows the buffer allocated for user authentication.
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Analysis
by VulDB Data Team • 09/03/2025
The stack-based buffer overflow vulnerability in FreeFloat FTP Server version 1.0.0 represents a critical security flaw that directly impacts the server's authentication mechanism and overall system integrity. This vulnerability specifically affects the USER command implementation where the server fails to properly validate the length of username input provided by clients. The flaw manifests when an attacker sends an excessively long string as a username parameter, causing the server to write beyond the bounds of the allocated stack buffer. This type of vulnerability falls under the common weakness enumeration CWE-121, which categorizes stack-based buffer overflows as a fundamental memory safety issue that can lead to arbitrary code execution. The vulnerability is particularly dangerous because it occurs during the initial authentication phase, providing attackers with a potential entry point to compromise the entire FTP server instance.
The technical exploitation of this buffer overflow leverages the predictable nature of stack memory layout in the FreeFloat FTP Server implementation. When the server processes the USER command with an oversized username string, the excess data overflows into adjacent memory locations, potentially corrupting the return address of the function or other critical stack variables. This memory corruption can be manipulated to redirect program execution flow to attacker-controlled code, effectively allowing remote code execution on the vulnerable system. The vulnerability is classified as a remote exploit since no local access is required, making it particularly attractive to attackers who can target the FTP server from any network location. The specific nature of the flaw indicates that the server uses a fixed-size buffer for username storage without proper bounds checking, which is a common pattern in legacy software implementations that do not follow modern secure coding practices.
The operational impact of this vulnerability extends beyond simple unauthorized access to encompass complete system compromise and potential data breach scenarios. An attacker who successfully exploits this vulnerability can gain full control over the FTP server, potentially leading to unauthorized file access, modification of sensitive data, or even use of the compromised server as a launching point for attacks against other systems within the network. The vulnerability affects the core authentication functionality of the FTP server, meaning that any user attempting to establish a connection could potentially trigger the exploit. This makes the vulnerability particularly dangerous in environments where the FTP server is publicly accessible or used by multiple users with varying levels of trust. The impact is further amplified by the fact that the vulnerability can be exploited without requiring authentication, allowing attackers to gain system-level privileges simply by sending a specially crafted username string.
Mitigation strategies for this vulnerability must address both immediate remediation and long-term architectural improvements to prevent similar issues in the future. The most effective immediate solution involves upgrading to a patched version of FreeFloat FTP Server or migrating to a more modern and secure FTP implementation that properly validates all input parameters. Organizations should also implement network-level restrictions such as firewall rules that limit access to the FTP service to trusted IP addresses only, reducing the attack surface for remote exploitation attempts. Additionally, network monitoring should be enhanced to detect unusual patterns in FTP traffic, particularly large USER command parameters that could indicate exploitation attempts. The vulnerability demonstrates the importance of following secure coding practices such as those outlined in the OWASP Secure Coding Practices and the CERT Secure Coding Standards, which emphasize the necessity of input validation and proper buffer management. Regular security assessments and penetration testing should be conducted to identify similar vulnerabilities in other legacy systems that may not have been updated to address known security flaws.