CVE-2006-2403 in FileZilla
Summary
by MITRE
Buffer overflow in FileZilla before 2.2.23 allows remote attackers to execute arbitrary commands via unknown attack vectors.
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Analysis
by VulDB Data Team • 06/18/2019
The vulnerability identified as CVE-2006-2403 represents a critical buffer overflow flaw in FileZilla FTP client software versions prior to 2.2.23. This vulnerability exposes the application to remote code execution attacks, making it a significant concern for organizations relying on FTP client software for file transfers. The buffer overflow occurs within the application's handling of data structures that process network communications, creating an exploitable condition that can be leveraged by remote attackers to gain unauthorized control over affected systems.
The technical nature of this flaw stems from inadequate input validation and memory management within FileZilla's network processing components. When the application receives data from remote FTP servers or clients, it fails to properly validate the size of incoming buffers, allowing attackers to craft malicious inputs that exceed allocated memory boundaries. This overflow can overwrite adjacent memory locations, potentially corrupting program execution flow and enabling attackers to inject and execute arbitrary code with the privileges of the affected user. The vulnerability's classification as a buffer overflow aligns with CWE-121, which specifically addresses stack-based buffer overflow conditions, and CWE-122, which covers heap-based buffer overflow scenarios that can occur in similar network processing applications.
The operational impact of CVE-2006-2403 extends beyond simple remote code execution, as it can enable attackers to establish persistent access to compromised systems. Attackers can leverage this vulnerability to install backdoors, exfiltrate sensitive data, or use compromised systems as launch points for further attacks within network environments. The remote nature of the exploit means that attackers do not require physical access to target systems, making the vulnerability particularly dangerous in enterprise environments where FTP clients are frequently used for business-critical file transfers. Organizations using older FileZilla versions face elevated risk of compromise, especially in environments where unpatched systems may be exposed to external network traffic or where internal network segmentation is insufficient to contain potential breaches.
Mitigation strategies for this vulnerability should prioritize immediate patching of FileZilla installations to version 2.2.23 or later, which includes fixes for the buffer overflow conditions. Organizations should implement network segmentation to limit exposure of FTP clients to untrusted networks and consider disabling unnecessary FTP client functionality where possible. Security monitoring should include detection of anomalous FTP client behavior and network traffic patterns that may indicate exploitation attempts. The vulnerability's characteristics align with ATT&CK technique T1059.007 for command and scripting interpreter, as successful exploitation would enable attackers to execute arbitrary commands on compromised systems. Additionally, implementing proper input validation and memory safety practices in network applications can help prevent similar vulnerabilities from occurring in other software components that process network data.