CVE-2005-3950 in NuFW
Summary
by MITRE
nuauth in NuFW 1.0.x before 1.0.16 and 1.1 allows authenticated users to cause a denial of service via malformed packets.
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Analysis
by VulDB Data Team • 07/14/2018
The vulnerability identified as CVE-2005-3950 affects the nuauth component within NuFW versions 1.0.x prior to 1.0.16 and 1.1, representing a significant security flaw that enables authenticated users to execute denial of service attacks through the manipulation of network packets. This issue resides within the authentication and authorization subsystem of the firewall software, specifically targeting the nuauth daemon responsible for handling user authentication requests. The flaw manifests when the system processes malformed packets that are crafted to exploit weaknesses in the packet parsing logic, potentially causing the authentication service to crash or become unresponsive.
The technical implementation of this vulnerability stems from insufficient input validation within the nuauth module, which fails to properly sanitize or validate packet structures received from authenticated users. When legitimate users submit packets containing malformed data or unexpected packet formats, the system's parsing routines encounter unexpected conditions that lead to abrupt termination or resource exhaustion. This represents a classic example of a buffer overread or improper input handling vulnerability that falls under CWE-129, which addresses improper validation of array indices. The vulnerability's impact is amplified by the fact that it requires only authenticated access, meaning that users who have already established legitimate connections or credentials can exploit this weakness to disrupt service availability.
From an operational perspective, this vulnerability presents a serious threat to network infrastructure security as it allows attackers to compromise service availability without requiring elevated privileges or complex exploitation techniques. The authenticated nature of the attack means that adversaries can leverage existing user accounts or credentials to perform denial of service operations, making the attack vector more accessible than many other vulnerabilities. Network administrators face the challenge of maintaining service availability while ensuring that legitimate users can authenticate properly, as the vulnerability creates a scenario where authorized users can inadvertently or deliberately cause system instability.
The attack pattern associated with CVE-2005-3950 aligns with several tactics described in the MITRE ATT&CK framework, particularly focusing on privilege escalation and denial of service operations. While the initial access requires authentication, the subsequent exploitation can be classified under privilege abuse and service disruption techniques. The vulnerability demonstrates how even authenticated users can be leveraged to create security incidents, making it particularly concerning for environments where user access management is critical. Organizations implementing NuFW solutions must consider the broader implications of this vulnerability within their security posture, as it represents a potential attack surface that could be exploited to compromise network availability.
Mitigation strategies for this vulnerability include immediate patching to versions 1.0.16 or later where the authentication handling has been corrected, implementing additional monitoring for anomalous packet patterns, and establishing network segmentation to limit the impact of potential exploitation. Security teams should also consider implementing rate limiting and connection monitoring to detect and prevent abuse of the authentication service. The fix typically involves strengthening input validation routines and implementing proper error handling mechanisms within the nuauth daemon to gracefully process malformed packets rather than allowing them to cause system instability. Organizations should also conduct regular security assessments to identify similar vulnerabilities in other network components and establish robust incident response procedures to address potential exploitation attempts.