CVE-2005-1323 in NetTerm
Summary
by MITRE
Buffer overflow in NetFtpd for NetTerm 5.1.1 and earlier allows remote attackers to execute arbitrary code via a long USER command.
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Analysis
by VulDB Data Team • 06/06/2019
The vulnerability identified as CVE-2005-1323 represents a critical buffer overflow flaw within the NetFtpd component of NetTerm 5.1.1 and earlier versions. This issue resides in the handling of USER command inputs, which are fundamental to ftp protocol authentication processes. The flaw manifests when the application fails to properly validate or limit the length of user-supplied data during the authentication phase, creating an exploitable condition that can be leveraged by remote attackers to gain unauthorized system access. The vulnerability specifically affects the ftp daemon implementation that processes user credentials, making it a direct target for malicious actors seeking to compromise systems running vulnerable versions of NetTerm software.
The technical implementation of this buffer overflow occurs when the NetFtpd service receives a USER command containing an excessively long string of characters. The application's internal buffer allocation does not adequately verify the input length against predefined boundaries, allowing attackers to overflow the allocated memory space. This memory corruption can overwrite adjacent memory locations including return addresses, function pointers, or other critical program state information. The flaw aligns with CWE-121, which describes heap-based buffer overflow conditions, and CWE-122, covering stack-based buffer overflow scenarios. When exploited successfully, the overflow can redirect program execution flow to malicious code injected by the attacker, potentially enabling complete system compromise.
From an operational impact perspective, this vulnerability poses significant risks to organizations relying on NetTerm 5.1.1 or earlier versions for their ftp services. Remote code execution capabilities allow attackers to bypass authentication mechanisms entirely and gain system-level privileges without legitimate credentials. The attack vector requires no local access or prior authentication, making it particularly dangerous as it can be exploited from anywhere on the internet. The vulnerability affects the core ftp service functionality, potentially disrupting legitimate user access while simultaneously providing attackers with persistent access to target systems. Network monitoring tools may detect unusual USER command patterns, but the initial exploitation often occurs without detection, especially when attackers use sophisticated techniques to avoid standard intrusion detection signatures.
Mitigation strategies for CVE-2005-1323 should prioritize immediate patching of affected systems to the latest NetTerm versions that address the buffer overflow condition. Organizations must implement network segmentation to limit exposure of vulnerable ftp services to external networks and establish strict access controls for ftp access points. Input validation measures should be enhanced to enforce maximum length restrictions on USER command parameters, with proper bounds checking implemented at the application layer. Security monitoring should include detection of unusually long USER command inputs that exceed normal operational parameters. The vulnerability demonstrates the importance of following secure coding practices and adheres to ATT&CK technique T1190, which covers exploitation of remote services through buffer overflow conditions. Regular security assessments and vulnerability scanning should be conducted to identify similar issues in legacy ftp implementations and ensure comprehensive protection against similar attack vectors. System administrators should also consider implementing additional layers of security such as ftp protocol restrictions, authentication monitoring, and regular security updates to prevent exploitation of known vulnerabilities in network services.