CVE-2006-6950 in FTPServer
Summary
by MITRE
Directory traversal vulnerability in Conti FTPServer 1.0 Build 2.8 allows remote attackers to read arbitrary files and list arbitrary directories via a .. (dot dot) in a filename argument.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 08/17/2018
The vulnerability identified as CVE-2006-6950 represents a critical directory traversal flaw within Conti FTPServer version 1.0 Build 2.8, classified under CWE-22 - Improper Limitation of a Pathname to a Restricted Directory. This weakness stems from insufficient input validation mechanisms that fail to properly sanitize user-supplied filename arguments before processing them within the file system. The vulnerability specifically manifests when attackers exploit the lack of proper path normalization and validation checks, allowing malicious users to manipulate file access through the use of .. (dot dot) sequences in filename parameters.
The technical exploitation of this vulnerability occurs at the application layer where the FTP server processes user requests without adequate sanitization of input parameters. When a user submits a filename containing directory traversal sequences such as ../ or ..\, the server fails to validate these inputs against a whitelist of acceptable characters or paths, thereby permitting access to files outside the intended directory structure. This flaw operates at the core of the server's file handling logic, where path resolution occurs without proper boundary enforcement. The vulnerability can be leveraged to read arbitrary files from the server's file system, potentially exposing sensitive configuration files, user credentials, or system information.
From an operational perspective, this vulnerability presents a significant risk to organizations relying on Conti FTPServer for file transfer operations. Remote attackers can exploit this weakness to gain unauthorized access to sensitive data stored on the server, potentially leading to complete system compromise. The impact extends beyond simple data theft, as attackers may use this access to establish persistent backdoors, escalate privileges, or deploy additional malicious payloads. The vulnerability's remote exploitability means that attackers do not require physical access to the server and can target the system from any location with network connectivity. This characteristic aligns with ATT&CK technique T1078 - Valid Accounts, as successful exploitation may lead to credential compromise or unauthorized access to privileged system resources.
The mitigation strategies for CVE-2006-6950 should focus on implementing robust input validation and sanitization mechanisms. Organizations should immediately apply patches or updates provided by the vendor to address this vulnerability. Additionally, implementing proper path validation that rejects any input containing directory traversal sequences represents a fundamental defensive measure. Network segmentation and access control lists can help limit the potential impact of exploitation, while monitoring and logging of FTP access attempts can aid in detecting unauthorized access attempts. The implementation of principle of least privilege for FTP server accounts and regular security audits of file system permissions further reduces the attack surface. Organizations should also consider implementing web application firewalls or intrusion detection systems that can detect and block suspicious traversal sequences in network traffic. The vulnerability demonstrates the critical importance of input validation in preventing path traversal attacks, which remain one of the most common and dangerous classes of vulnerabilities in networked applications according to industry security frameworks and threat intelligence reports.