CVE-2016-5362 in Neutron
Summary
by MITRE
The IPTables firewall in OpenStack Neutron 7.0.x through 7.0.4 (Liberty) and 8.0.x through 8.1.0 (Mitaka) allows remote attackers to bypass an intended DHCP-spoofing protection mechanism and consequently cause a denial of service or intercept network traffic via a crafted DHCP discovery message.
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Analysis
by VulDB Data Team • 03/04/2025
The vulnerability identified as CVE-2016-5362 represents a critical flaw in OpenStack Neutron's IPTables firewall implementation that specifically affects versions 7.0.x through 7.0.4 (Liberty release) and 8.0.x through 8.1.0 (Mitaka release). This security weakness resides within the DHCP-spoofing protection mechanisms that are fundamental to maintaining network integrity and preventing unauthorized network access within OpenStack cloud environments. The flaw manifests when the system fails to properly validate DHCP discovery messages, creating an avenue for malicious actors to exploit the network security controls that are meant to prevent unauthorized DHCP servers from operating within the virtual network infrastructure.
The technical implementation of this vulnerability stems from insufficient input validation within the DHCP processing pipeline of Neutron's IPTables firewall component. When a crafted DHCP discovery message is transmitted, the system does not adequately verify the authenticity or legitimacy of the message source, allowing attackers to bypass the intended security controls that should prevent unauthorized DHCP responses. This failure creates a condition where malicious actors can inject false DHCP information into the network, effectively undermining the network segmentation and access control mechanisms that are critical for cloud security. The vulnerability operates at the network layer, specifically targeting the dynamic host configuration protocol implementation within the virtual networking stack of OpenStack deployments.
The operational impact of CVE-2016-5362 extends beyond simple network disruption to encompass potential data interception and service denial scenarios that can severely compromise cloud infrastructure security. Remote attackers exploiting this vulnerability can establish unauthorized network access points, potentially enabling them to monitor traffic flows, intercept sensitive communications, or redirect network traffic to malicious endpoints. The denial of service aspect of this vulnerability can manifest as legitimate network services becoming unavailable due to the disruption of legitimate DHCP operations, while the traffic interception capability provides attackers with opportunities to perform man-in-the-middle attacks against virtual machines and network services. This vulnerability directly impacts the core security principles of confidentiality, integrity, and availability within OpenStack cloud deployments.
Organizations utilizing affected OpenStack Neutron versions should implement immediate mitigations including applying the vendor-provided patches that address the DHCP validation logic within the IPTables firewall implementation. The fix typically involves strengthening the input validation mechanisms to properly authenticate DHCP discovery messages and ensure that only legitimate network infrastructure can respond to DHCP requests. Additionally, network administrators should consider implementing additional monitoring and anomaly detection measures to identify unusual DHCP activity patterns that may indicate exploitation attempts. This vulnerability aligns with CWE-20, which describes improper input validation, and maps to ATT&CK technique T1071.004 for application layer protocol usage in network communications. Organizations should also review their overall network security posture and consider implementing network segmentation strategies that limit the impact of potential DHCP-related attacks within their cloud environments.