CVE-2007-6473 in WFTPD Pro Explorer
Summary
by MITRE
Heap-based buffer overflow in Texas Imperial Software WFTPD Pro Explorer 1.0 allows remote FTP servers to execute arbitrary code via a long reply to a LIST command.
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Analysis
by VulDB Data Team • 06/01/2025
The vulnerability identified as CVE-2007-6473 represents a critical heap-based buffer overflow in the WFTPD Pro Explorer 1.0 FTP client software developed by Texas Imperial Software. This flaw exists within the client's handling of FTP server responses, specifically when processing the LIST command which is commonly used to retrieve directory listings from FTP servers. The vulnerability arises from insufficient input validation and bounds checking in the client application's memory management routines, creating an exploitable condition that can be triggered by maliciously crafted FTP server responses.
The technical implementation of this vulnerability stems from the client's failure to properly validate the length of server responses to the LIST command before copying data into fixed-size heap-allocated buffers. When a remote FTP server sends a particularly long reply containing more data than the allocated buffer can accommodate, the excess data overflows into adjacent memory regions, potentially corrupting heap metadata and executable code. This heap corruption can be carefully manipulated by attackers to overwrite return addresses, function pointers, or other critical program state information, enabling arbitrary code execution with the privileges of the affected user running the WFTPD client.
The operational impact of this vulnerability extends beyond simple remote code execution, as it represents a significant threat to the security of systems that rely on FTP clients for file transfers and directory browsing operations. Attackers can exploit this vulnerability by setting up a malicious FTP server that responds to LIST commands with oversized data payloads, effectively allowing remote attackers to compromise systems running vulnerable versions of WFTPD Pro Explorer 1.0 without requiring any local access or authentication. The attack vector is particularly concerning because it leverages the legitimate FTP protocol functionality, making detection more difficult and potentially allowing for stealthy exploitation in network environments where FTP traffic is common.
This vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions, and demonstrates characteristics consistent with attack patterns found in the MITRE ATT&CK framework under the T1203 technique for "Exploitation for Client Execution." The flaw represents a classic example of insufficient input validation in network protocol implementations, where the client software fails to properly sanitize server responses before processing them. Organizations using vulnerable versions of this FTP client should immediately implement mitigations including software updates from the vendor, network segmentation to limit exposure, and firewall rules that restrict FTP server access to trusted sources. Additionally, users should be educated about the risks of connecting to untrusted FTP servers and the importance of maintaining current security patches for all network client applications. The vulnerability underscores the critical importance of proper memory management and input validation in network protocol implementations, particularly for applications that handle untrusted data from remote servers.