CVE-2001-0582 in CrushFTP Server
Summary
by MITRE
Ben Spink CrushFTP FTP Server 2.1.6 and earlier allows a local attacker to access arbitrary files via a .. (dot dot) attack, or variations, in (1) GET, (2) CD, (3) NLST, (4) SIZE, (5) RETR.
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Analysis
by VulDB Data Team • 12/22/2024
The vulnerability identified as CVE-2001-0582 represents a critical directory traversal flaw in the Ben Spink CrushFTP FTP Server version 2.1.6 and earlier releases. This security weakness stems from inadequate input validation mechanisms within the server's file access routines, specifically affecting five core FTP commands that handle file operations. The flaw enables local attackers to bypass normal file access controls and retrieve arbitrary files from the system by exploiting path traversal techniques using dot-dot sequences. The vulnerability operates at the file system level where the server fails to properly sanitize user-supplied paths before processing file requests, creating a direct pathway for unauthorized data access.
The technical implementation of this vulnerability involves the exploitation of the .. (dot dot) traversal sequence within the FTP protocol commands GET, CD, NLST, SIZE, and RETR. When these commands receive input containing directory traversal sequences, the CrushFTP server fails to normalize or validate the paths, allowing attackers to navigate outside the intended directory structure. This occurs because the server does not properly implement path resolution logic that would normally prevent access to parent directories or files outside the designated FTP root. The flaw essentially allows attackers to specify paths that include .. components, enabling them to traverse up the directory tree and access files that should remain restricted. This type of vulnerability is classified under CWE-22 as "Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')" and represents a fundamental flaw in access control implementation.
The operational impact of CVE-2001-0582 extends beyond simple unauthorized file access to encompass potential system compromise and data exfiltration capabilities. Local attackers can leverage this vulnerability to access sensitive configuration files, user credentials stored in plain text, application logs, and potentially system files that contain critical information. The vulnerability affects the core FTP functionality and can be exploited through various attack vectors since it impacts multiple commands that handle file system operations. This creates a broad attack surface where even minimal user access can escalate to full system compromise. The vulnerability also aligns with ATT&CK technique T1078 which covers legitimate accounts and T1566 which involves credential access through various methods including path traversal attacks. Organizations running affected versions of CrushFTP face significant risk of data breaches and system infiltration, particularly in environments where FTP servers are used for file sharing and data transfer operations.
Mitigation strategies for this vulnerability require immediate implementation of software updates to versions that address the path traversal flaw. System administrators should apply the vendor-provided patches or upgrade to newer versions of the CrushFTP server that properly validate and sanitize all user-supplied paths before processing file operations. Additionally, implementing network segmentation and access controls can limit the attack surface by restricting local access to FTP servers and enforcing strict authentication mechanisms. The solution should include proper input validation at all levels of the application stack, particularly focusing on path normalization and access control enforcement. Security monitoring should be enhanced to detect unusual FTP activity patterns that might indicate exploitation attempts. Organizations should also consider implementing intrusion detection systems that can identify and alert on directory traversal attempts, as well as regular security audits to ensure that file system access controls remain properly configured. The vulnerability demonstrates the critical importance of proper input validation and access control implementation in network services, particularly those handling file system operations where path traversal attacks can lead to complete system compromise.