CVE-2005-1873 in FTP
Summary
by MITRE
Multiple buffer overflows in Crob FTP 3.6.1, and possibly earlier versions, allow remote attackers to execute arbitrary code via (1) an FTP command with a large string followed by the RMD command with a long string or (2) a globbing ("*") character followed by a long string.
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Analysis
by VulDB Data Team • 06/07/2019
The vulnerability identified as CVE-2005-1873 represents a critical buffer overflow issue affecting Crob FTP version 3.6.1 and potentially older iterations. This flaw resides within the file transfer protocol client implementation and demonstrates a classic security weakness that has been documented in the cybersecurity community for over a decade. The vulnerability stems from insufficient input validation and improper memory management within the FTP client's command processing mechanisms, creating exploitable conditions that can be leveraged by remote attackers to gain unauthorized system access. The affected software demonstrates poor defensive programming practices that fail to enforce proper bounds checking on user-supplied data, particularly in the context of FTP command sequences.
The technical exploitation of this vulnerability occurs through two distinct attack vectors that both rely on manipulating FTP command sequences to trigger buffer overflows. The first vector involves executing an FTP command with an excessively long string followed by a RMD (Remove Directory) command containing a lengthy string, while the second vector utilizes globbing characters combined with extended string inputs. Both attack methods exploit the underlying flaw in how the FTP client processes and stores command arguments in memory buffers that lack adequate size validation. The buffer overflow conditions occur when the program attempts to write data beyond the allocated memory boundaries, potentially overwriting adjacent memory regions including return addresses and control data structures. This type of vulnerability falls under CWE-121, which specifically addresses stack-based buffer overflow conditions, and represents a fundamental weakness in software memory management practices.
The operational impact of this vulnerability extends beyond simple code execution, as successful exploitation can provide attackers with complete system compromise capabilities. Remote attackers who successfully exploit this vulnerability can execute arbitrary code with the privileges of the affected FTP client process, potentially leading to full system control, data exfiltration, or further network infiltration. The attack vectors are particularly concerning because they can be executed without authentication, making them accessible to anyone who can establish an FTP connection to the vulnerable system. The vulnerability's persistence across multiple versions indicates a systemic design flaw that was not adequately addressed through the software's development lifecycle, highlighting the importance of proper security testing and code review practices. Organizations running affected FTP clients face significant risk of unauthorized access and potential data breaches, as the vulnerability can be exploited from external networks without requiring any special privileges or access to the local system.
Mitigation strategies for this vulnerability should focus on immediate remediation through software updates to the latest available versions of Crob FTP that contain proper bounds checking and input validation mechanisms. System administrators should implement network segmentation and access controls to limit exposure of FTP services to untrusted networks, while also considering the deployment of intrusion detection systems to monitor for suspicious FTP command sequences. The vulnerability demonstrates the importance of following secure coding practices such as those recommended in the software security development lifecycle, including input validation, bounds checking, and proper error handling. Organizations should also consider implementing network-based controls such as firewall rules that restrict FTP traffic to necessary internal systems only, and conduct regular vulnerability assessments to identify other potentially affected software components. The remediation approach should also include monitoring for exploitation attempts through log analysis and implementing proper patch management procedures to ensure timely deployment of security updates across all affected systems. This vulnerability serves as a reminder of the critical importance of maintaining up-to-date software and implementing proper security controls to prevent exploitation of known weaknesses in network services.