CVE-2002-1746 in Vtun
Summary
by MITRE
Vtun 2.5b1 allows remote attackers to inject data into user sessions by sniffing and replaying packets.
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Analysis
by VulDB Data Team • 06/09/2018
The vulnerability identified as CVE-2002-1746 affects Vtun version 2.5b1, a virtual private network implementation that provides secure tunneling capabilities for network communications. This security flaw represents a significant weakness in the protocol's authentication and session management mechanisms, potentially allowing malicious actors to compromise user sessions and gain unauthorized access to network resources. The vulnerability specifically targets the integrity and confidentiality aspects of the vtun protocol, which is designed to establish encrypted connections between remote systems while maintaining secure communication channels.
The technical flaw stems from insufficient packet validation and replay protection mechanisms within the vtun implementation. When attackers can successfully sniff network traffic and replay captured packets, they exploit weaknesses in the session identification and packet ordering validation processes. This allows them to inject malicious data into existing user sessions without proper authentication or authorization. The vulnerability operates at the network protocol level, specifically affecting how the system handles packet sequence numbers, session identifiers, and authentication tokens. According to CWE standards, this represents a weakness in authentication and session management, specifically categorized under CWE-310, which deals with cryptographic issues and authentication failures. The attack vector involves passive network monitoring followed by active packet manipulation, making it particularly dangerous in environments where network traffic is not adequately protected.
The operational impact of this vulnerability extends beyond simple data injection, as it can lead to complete session hijacking and unauthorized access to protected network resources. Attackers can potentially execute arbitrary commands, access sensitive data, or disrupt network services by exploiting the replay capabilities. This vulnerability undermines the fundamental security assumptions of the vtun protocol, which relies on the integrity of network communications to maintain secure sessions. The threat is particularly severe in environments where vtun is used for remote access to corporate networks, as it allows attackers to establish persistent unauthorized access to internal systems. The vulnerability also aligns with ATT&CK framework techniques related to credential access and defense evasion, as it enables attackers to maintain access without detection while potentially bypassing traditional authentication mechanisms. Organizations using vtun 2.5b1 are particularly at risk because the vulnerability can be exploited with relatively simple network monitoring tools and packet replay capabilities.
Mitigation strategies for CVE-2002-1746 require immediate attention and implementation of multiple security controls. The primary solution involves upgrading to a patched version of vtun that implements proper packet validation and replay protection mechanisms. System administrators should also implement network segmentation and monitoring to detect anomalous packet patterns that might indicate replay attacks. Additional protective measures include deploying network intrusion detection systems specifically configured to identify suspicious session replay activities and implementing stronger authentication mechanisms such as multi-factor authentication. Organizations should also consider implementing encrypted network monitoring solutions to prevent attackers from easily sniffing network traffic. The vulnerability demonstrates the importance of proper session management and packet integrity validation, which are fundamental requirements for secure network communications. Security teams should conduct comprehensive network assessments to identify any systems running vulnerable versions of vtun and ensure that all network protocols implement adequate protection against replay attacks. This vulnerability serves as a reminder of the critical need for regular security updates and proper protocol validation in network security implementations.