CVE-2007-3548 in W3Filer
Summary
by MITRE
Stack-based buffer overflow in W3Filer 2.1.3 allows remote FTP servers to cause a denial of service (application hang or crash) and possibly execute arbitrary code by sending a large banner to a client that is sending a file.
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Analysis
by VulDB Data Team • 09/23/2024
The vulnerability identified as CVE-2007-3548 represents a critical stack-based buffer overflow flaw in W3Filer version 2.1.3 that fundamentally compromises the application's memory integrity and operational stability. This vulnerability specifically manifests when the application processes a maliciously crafted banner message from a remote FTP server during file transfer operations, creating a dangerous condition where attacker-controlled data exceeds the allocated buffer space on the stack. The flaw resides in the application's handling of FTP server responses, particularly the initial banner message that establishes the connection, making it a prime target for exploitation during the initial handshake phase of FTP communications.
The technical implementation of this vulnerability leverages the fundamental principle of stack memory management where insufficient bounds checking allows an attacker to overwrite adjacent memory locations including return addresses and stack canaries. When a remote FTP server sends a banner message exceeding the predefined buffer capacity, the excess data overflows into adjacent stack memory regions, potentially corrupting the program's execution flow. This overflow condition creates multiple attack vectors including application crashes, complete system hangs, and in some scenarios, arbitrary code execution through careful manipulation of the overwritten memory locations. The vulnerability operates at the application layer and requires no authentication or privileged access, making it particularly dangerous for remote exploitation.
The operational impact of this vulnerability extends beyond simple denial of service conditions to potentially enable complete system compromise. When an application crashes or hangs due to this buffer overflow, it creates service disruption that can affect legitimate users and potentially provide attackers with opportunities to conduct further reconnaissance or establish persistent access. The possibility of arbitrary code execution through this vulnerability aligns with common attack patterns documented in the attack tree model, where initial access points are leveraged to escalate privileges and establish backdoors. The vulnerability affects systems running W3Filer 2.1.3 and similar applications that implement similar FTP client functionality without proper input validation, creating widespread exposure across affected environments.
Mitigation strategies for CVE-2007-3548 should focus on immediate patching of the affected W3Filer version to address the buffer overflow conditions through proper bounds checking and input validation mechanisms. Organizations should implement network segmentation and access controls to limit exposure of vulnerable systems to untrusted FTP servers, particularly in environments where automatic file transfers occur. The implementation of intrusion detection systems capable of identifying suspicious FTP banner patterns and monitoring for abnormal application behavior can provide early warning capabilities. Additionally, system administrators should consider disabling unnecessary FTP client functionality and implementing proper network monitoring to detect and prevent exploitation attempts. This vulnerability demonstrates the critical importance of input validation and memory safety practices, aligning with common security recommendations from standards such as the CWE catalog which classifies this as a classic buffer overflow condition under CWE-121. The ATT&CK framework would categorize this vulnerability under initial access and execution phases, where adversaries establish footholds through application-level exploits before potentially escalating privileges or moving laterally within compromised networks.