CVE-2005-3524 in linux-ftpd-ssl
Summary
by MITRE
Buffer overflow in the SSL-ready version of linux-ftpd (linux-ftpd-ssl) 0.17 allows remote attackers to execute arbitrary code by creating a long directory name, then executing the XPWD command.
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Analysis
by VulDB Data Team • 01/07/2025
The vulnerability identified as CVE-2005-3524 represents a critical buffer overflow flaw in the SSL-ready version of linux-ftpd version 0.17. This issue specifically affects the handling of directory names during FTP operations, creating a pathway for remote code execution that has significant implications for system security. The vulnerability exists within the ftpd server implementation that supports SSL/TLS encryption, making it particularly concerning for environments where secure file transfer protocols are essential. The flaw manifests when an attacker constructs an excessively long directory name that exceeds the allocated buffer space, ultimately leading to memory corruption that can be exploited to gain unauthorized system access. This vulnerability directly maps to CWE-121, which describes heap-based buffer overflow conditions, and represents a classic example of insufficient input validation in network services.
The technical exploitation of this vulnerability occurs through a specific sequence of commands that manipulate the FTP server's response handling mechanism. When a malicious user creates a directory with an overly long name and subsequently executes the XPWD command, the server's internal buffer management fails to properly handle the excessive data length. This buffer overflow condition allows attackers to overwrite adjacent memory locations, potentially corrupting critical program execution flow. The overflow specifically affects the server's ability to process directory listings and responses, enabling attackers to inject malicious code into the execution context. The vulnerability is classified under the ATT&CK technique T1059.007 for command and scripting interpreter, as successful exploitation would allow adversaries to execute arbitrary commands on the compromised system. The attack vector requires network access to the FTP service and can be executed remotely without authentication, making it particularly dangerous for publicly accessible servers.
The operational impact of this vulnerability extends beyond simple code execution to encompass complete system compromise and potential data breaches. Servers running the vulnerable version of linux-ftpd are at risk of being fully compromised by remote attackers who can execute arbitrary commands with the privileges of the ftpd process. This typically means the attacker can access, modify, or delete files within the server's file system, potentially leading to unauthorized data access or complete system takeover. The vulnerability affects not only the immediate server but also any systems that trust or depend on the compromised FTP service for file transfers. Organizations utilizing this software in production environments face significant risk exposure, particularly in scenarios where the FTP server is accessible from untrusted networks or where it handles sensitive data. The vulnerability also impacts compliance with security standards such as pci dss and iso 27001, as it represents a critical weakness in the organization's security infrastructure.
Mitigation strategies for CVE-2005-3524 require immediate action to address the buffer overflow condition through software updates and operational security measures. The most effective solution involves upgrading to a patched version of linux-ftpd that properly validates input lengths and implements secure buffer management practices. Organizations should also consider implementing network segmentation to limit access to FTP services and deploy intrusion detection systems to monitor for exploitation attempts. Additional protective measures include disabling unnecessary FTP commands, implementing strict input validation at the network level, and conducting regular security assessments of file transfer services. The vulnerability demonstrates the importance of proper memory management in network services and underscores the need for regular security updates. Organizations should also implement monitoring for unusual directory name lengths and command sequences that might indicate attempted exploitation. Given the age of this vulnerability and the specific software version affected, replacement of the legacy ftpd implementation with modern secure alternatives such as vsftpd or proftpd is strongly recommended to eliminate exposure to similar buffer overflow conditions.