CVE-2010-4149 in Fresh FTP
Summary
by MITRE
Directory traversal vulnerability in FreshWebMaster Fresh FTP 5.36, 5.37, and possibly earlier, allows remote FTP servers to write arbitrary files via a "..\" (dot dot backslash) in a filename. NOTE: some of these details are obtained from third party information.
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Analysis
by VulDB Data Team • 01/04/2018
The CVE-2010-4149 vulnerability represents a critical directory traversal flaw in FreshWebMaster Fresh FTP versions 5.36, 5.37, and potentially earlier releases. This vulnerability stems from inadequate input validation mechanisms within the FTP client software, specifically when processing filenames containing malicious directory traversal sequences. The flaw enables remote FTP servers to manipulate the client's file system operations by exploiting a "..\" pattern in filenames, which should normally be treated as invalid or sanitized before file operations are executed.
The technical implementation of this vulnerability occurs at the file system interaction layer where the FTP client fails to properly sanitize or validate filenames before attempting to create or write files. When a remote FTP server sends a filename containing "..\" sequences, the client processes these sequences without proper boundary checks, allowing the attacker to navigate outside the intended directory structure. This type of vulnerability maps directly to CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal attacks. The flaw essentially allows attackers to write files to arbitrary locations on the victim's file system, potentially leading to privilege escalation or system compromise.
The operational impact of CVE-2010-4149 is significant as it provides remote attackers with the capability to execute arbitrary file operations on vulnerable systems. An attacker could leverage this vulnerability to overwrite critical system files, install malicious software, or create backdoor access points. The attack vector involves a remote FTP server that has already established a connection with the vulnerable client, making it particularly dangerous in environments where users frequently connect to untrusted FTP servers. This vulnerability directly aligns with ATT&CK technique T1059.007 for Windows Command Shell and T1078 for valid accounts, as the successful exploitation could lead to persistent access and command execution capabilities.
Mitigation strategies for this vulnerability should focus on immediate software updates to patched versions of Fresh FTP, as well as implementing network-level restrictions such as firewall rules that prevent connections to untrusted FTP servers. System administrators should also consider implementing application whitelisting policies that restrict FTP client operations to specific directories, and establish monitoring procedures for unusual file system activities. The vulnerability highlights the importance of input validation and proper file system access controls, which are fundamental security principles that align with defense-in-depth strategies recommended by security frameworks such as NIST SP 800-53 and ISO 27001. Organizations should also conduct regular security assessments to identify similar vulnerabilities in other FTP client implementations and ensure that all file system operations properly validate and sanitize user-provided input to prevent similar directory traversal scenarios.