CVE-2014-3955 in FreeBSD
Summary
by MITRE
routed in FreeBSD 8.4 through 10.1-RC2 allows remote attackers to cause a denial of service (assertion failure and daemon exit) via an RIP request from a source not on a directly connected network.
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Analysis
by VulDB Data Team • 02/23/2022
The vulnerability identified as CVE-2014-3955 affects the routed daemon in FreeBSD versions ranging from 8.4 through 10.1-RC2. This issue represents a significant denial of service weakness that can be exploited by remote attackers to disrupt network routing services. The routed daemon serves as a critical component in FreeBSD systems, responsible for managing dynamic routing information and maintaining network connectivity through the implementation of the Routing Information Protocol. When an attacker sends a malicious RIP request from a source that is not directly connected to the network, the daemon experiences an assertion failure that results in its abrupt termination. This behavior creates a cascading effect where network routing functionality becomes compromised, potentially leading to complete network partitioning or service disruption across affected systems.
The technical flaw stems from inadequate validation of RIP request sources within the routed daemon implementation. Specifically, the daemon fails to properly verify that incoming RIP requests originate from directly connected networks before processing them. This validation gap allows attackers to craft malicious RIP packets with spoofed source addresses that appear to come from non-directly connected networks. When the daemon encounters such requests, it triggers an internal assertion check that fails, causing the daemon to exit unexpectedly. The underlying cause can be traced to CWE-20, which encompasses improper input validation issues, and more specifically relates to CWE-1104 which addresses the lack of proper source address validation in network protocols. This vulnerability operates at the network layer of the OSI model and demonstrates how insufficient boundary checks in routing protocols can lead to system instability.
The operational impact of this vulnerability extends beyond simple service disruption to potentially compromise network reliability and availability. When the routed daemon terminates due to assertion failure, it leaves the affected system without active routing capabilities, which can result in complete network isolation for that particular node. Network administrators may experience difficulties in maintaining connectivity as routing tables become stale and new routes cannot be properly learned or advertised. The vulnerability affects systems that rely on RIP as their primary routing protocol, which includes many enterprise and small business networks. The remote exploitation aspect means that attackers do not need physical access or network proximity to cause disruption, making this a particularly concerning weakness for network infrastructure. From an ATT&CK framework perspective, this vulnerability maps to T1499.004 which covers network disruption techniques, specifically targeting the availability of network services through daemon termination.
Mitigation strategies for CVE-2014-3955 involve several approaches that address both immediate protection and long-term system hardening. The most effective immediate solution is to upgrade to FreeBSD versions that contain the patched routed daemon implementation, specifically versions beyond 10.1-RC2 where the vulnerability has been resolved. System administrators should also implement network segmentation and access control measures to limit which hosts can communicate with routing daemons, effectively reducing the attack surface. Network administrators can deploy firewall rules that filter RIP traffic based on source address validation, ensuring that only legitimate directly connected network sources can communicate with routing daemons. Additionally, implementing monitoring and alerting systems can help detect unusual routing behavior or daemon termination events that may indicate exploitation attempts. The vulnerability highlights the importance of proper input validation and the need for robust error handling in network services, particularly those that process external routing information. Organizations should also consider implementing redundant routing protocols and failover mechanisms to ensure network resilience against such disruptions. Regular security assessments and vulnerability scanning should include checks for outdated routing daemon versions to prevent exploitation of similar vulnerabilities in the broader network infrastructure.