CVE-2006-6565 in Server
Summary
by MITRE
FileZilla Server before 0.9.22 allows remote attackers to cause a denial of service (crash) via a wildcard argument to the (1) LIST or (2) NLST commands, which results in a NULL pointer dereference, a different set of vectors than CVE-2006-6564. NOTE: CVE analysis suggests that the problem might be due to a malformed PORT command.
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Analysis
by VulDB Data Team • 08/11/2024
The vulnerability identified as CVE-2006-6565 affects FileZilla Server versions prior to 0.9.22 and represents a critical denial of service flaw that can be exploited by remote attackers to crash the server application. This vulnerability specifically targets the LIST and NLST command implementations within the FTP server software, making it particularly dangerous in environments where file transfer operations are frequently performed. The issue manifests when maliciously crafted wildcard arguments are submitted to these commands, leading to a NULL pointer dereference condition that ultimately results in application crash and service disruption.
The technical exploitation of this vulnerability occurs through the manipulation of FTP protocol commands that are designed to list directory contents. When an attacker submits a malformed wildcard argument to either the LIST or NLST commands, the server processes this input without proper validation, causing the application to attempt to dereference a NULL pointer in its memory management routines. This particular NULL pointer dereference represents a fundamental programming error that violates standard software security practices and can be classified under CWE-476 as a NULL Pointer Dereference. The vulnerability is distinct from CVE-2006-6564, indicating that it involves different code paths or implementation flaws within the server software, though both vulnerabilities relate to FTP command processing.
The operational impact of this vulnerability extends beyond simple service interruption, as it can be leveraged to disrupt file sharing operations and potentially impact business continuity for organizations relying on FileZilla Server for their file transfer infrastructure. Attackers can repeatedly exploit this flaw to maintain persistent denial of service conditions, making it particularly problematic for servers that handle critical file transfer operations or serve multiple concurrent users. The vulnerability's remote exploitability means that attackers do not need physical access to the server or local network privileges, making it accessible from any location with network connectivity to the affected FTP server. This characteristic aligns with ATT&CK technique T1499.004 for Network Denial of Service, where adversaries leverage application-level vulnerabilities to disrupt services.
The underlying issue may also be connected to improper handling of PORT commands as suggested by the CVE analysis, indicating that the vulnerability could stem from broader protocol parsing inconsistencies within the server implementation. This suggests that the flaw might not be isolated to just the LIST and NLST commands but could potentially affect other FTP operations that depend on similar parsing mechanisms. Organizations should consider the broader implications of this vulnerability when assessing their network security posture, particularly in environments where multiple FTP operations are performed or where the server operates in high-traffic conditions.
Mitigation strategies for CVE-2006-6565 should focus on immediate patching to FileZilla Server version 0.9.22 or later, which contains the necessary code modifications to properly validate wildcard arguments and prevent NULL pointer dereference conditions. Network administrators should implement monitoring solutions to detect unusual FTP command patterns that might indicate exploitation attempts, while also considering firewall rules that limit FTP traffic to trusted sources where possible. Additionally, organizations should conduct comprehensive security assessments of their FTP server configurations and implement proper input validation measures to prevent similar vulnerabilities from emerging in other applications or services. The vulnerability serves as a reminder of the importance of proper memory management and input validation in server applications, particularly those handling network protocols that are subject to malicious manipulation.