CVE-2009-3484 in Core FTP
Summary
by MITRE
Stack-based buffer overflow in Core FTP 2.1 build 1612 allows user-assisted remote attackers to execute arbitrary code via a long hostname in an FTP server entry in a site backup file. NOTE: some of these details are obtained from third party information.
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Analysis
by VulDB Data Team • 09/28/2025
The vulnerability identified as CVE-2009-3484 represents a critical stack-based buffer overflow flaw in Core FTP version 2.1 build 1612 that enables remote attackers to execute arbitrary code through a specially crafted hostname parameter. This vulnerability resides within the application's handling of FTP server entries stored in site backup files, making it particularly dangerous as it can be triggered during normal operational procedures when users import or restore FTP site configurations. The buffer overflow occurs when the application processes a hostname string that exceeds the allocated stack buffer space, leading to memory corruption that can be exploited to overwrite critical program execution flow.
The technical implementation of this vulnerability follows a classic stack-based buffer overflow pattern where insufficient input validation allows an attacker to provide a hostname string that surpasses the predetermined buffer limits. When Core FTP processes the site backup file containing the malicious hostname, the application fails to properly bounds-check the input data before copying it into a fixed-size stack buffer. This oversight creates a condition where the excess data overflows into adjacent memory locations, potentially overwriting return addresses, function pointers, or other critical control data structures. The vulnerability is classified under CWE-121 as a stack-based buffer overflow, which directly maps to the ATT&CK technique T1059.007 for command and script injection through application vulnerabilities.
The operational impact of this vulnerability extends beyond simple code execution as it provides attackers with a means to gain unauthorized access to systems running vulnerable versions of Core FTP. Attackers can leverage this vulnerability through user-assisted remote exploitation, meaning they need to convince a victim to import a malicious site backup file containing the crafted hostname. This attack vector is particularly concerning in enterprise environments where users may regularly import configuration files from various sources or where administrators might inadvertently restore compromised backup data. The exploitation can result in complete system compromise, data exfiltration, or establishment of persistent backdoors within the affected network infrastructure.
Mitigation strategies for CVE-2009-3484 require immediate action including updating to a patched version of Core FTP where input validation has been properly implemented to prevent buffer overflows. Organizations should implement strict file validation procedures for backup files and consider disabling automatic import functionality for untrusted sources. Network segmentation and access controls can help limit the potential damage from successful exploitation, while regular security audits should verify that no vulnerable installations exist within the organization. The vulnerability also highlights the importance of input sanitization and bounds checking in application development, aligning with security best practices outlined in the OWASP Top Ten and NIST Cybersecurity Framework. Additionally, security awareness training for users can help prevent social engineering attacks that might lead to the import of malicious backup files.