CVE-2008-5431 in Teamtek Universal FTP Server
Summary
by MITRE
Teamtek Universal FTP Server 1.0.44 allows remote attackers to cause a denial of service via (1) a certain CWD command, (2) a long LIST command, or (3) a certain PORT command.
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Analysis
by VulDB Data Team • 12/01/2017
The Teamtek Universal FTP Server version 1.0.44 contains critical vulnerabilities that enable remote attackers to execute denial of service attacks through specifically crafted FTP commands. This vulnerability affects the server's handling of three distinct command types that when improperly constructed can cause the service to become unresponsive or crash entirely. The vulnerability stems from insufficient input validation and error handling within the server's command processing logic, creating exploitable conditions that can be leveraged by malicious actors without requiring authentication or privileged access.
The technical flaw manifests in three specific attack vectors that exploit different aspects of the FTP protocol implementation. The first vector involves a particular CWD command that when sent to the server triggers an unhandled exception or memory corruption condition. The second vulnerability occurs during processing of extended LIST commands that exceed normal parameter limits, causing buffer overflows or stack corruption. The third attack vector targets the PORT command with specific parameters that lead to improper state management within the server's connection handling routines. These command processing flaws represent classic examples of input validation failures that can be categorized under common weakness enumeration CWE-121, which deals with stack-based buffer overflow conditions.
The operational impact of this vulnerability extends beyond simple service disruption as it can be exploited by attackers to maintain persistent availability issues against critical file transfer infrastructure. Organizations relying on this FTP server implementation face significant risks including potential data accessibility problems, service unavailability during critical business operations, and possible escalation to more severe attacks if the server is part of a larger network infrastructure. The vulnerability's remote exploitability means that attackers can initiate attacks from any location without requiring physical access to the server, making it particularly dangerous in enterprise environments where such services may be exposed to untrusted networks. According to the attack technique framework, this vulnerability aligns with ATT&CK technique T1499 which covers network denial of service attacks and T1566 which involves malicious file transfers that can be used to establish persistent access points.
Mitigation strategies for this vulnerability should include immediate patching of the Teamtek Universal FTP Server to the latest version that addresses these specific command handling issues. Organizations should also implement network segmentation to limit exposure of FTP services to trusted networks only, deploy intrusion detection systems to monitor for suspicious FTP command patterns, and consider implementing rate limiting mechanisms to prevent exploitation attempts. Additionally, system administrators should conduct thorough security assessments of all FTP server implementations within their environments and consider migrating to more robust and actively maintained FTP solutions that have better security track records and regular update cycles. The vulnerability demonstrates the importance of proper input validation and error handling in network services, emphasizing that even seemingly simple protocol implementations can contain critical security flaws that require comprehensive security testing and monitoring approaches.