CVE-2016-5363 in Neutron
Summary
by MITRE
The IPTables firewall in OpenStack Neutron before 7.0.4 and 8.0.0 through 8.1.0 allows remote attackers to bypass an intended MAC-spoofing protection mechanism and consequently cause a denial of service or intercept network traffic via (1) a crafted DHCP discovery message or (2) crafted non-IP traffic.
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Analysis
by VulDB Data Team • 03/04/2025
The vulnerability identified as CVE-2016-5363 represents a critical flaw in OpenStack Neutron's IPTables firewall implementation that undermines fundamental network security controls. This issue affects versions prior to 7.0.4 and specifically impacts the 8.0.0 through 8.1.0 release series, creating a persistent security gap that allows remote attackers to circumvent MAC-spoofing protections that are essential for maintaining network isolation and integrity within cloud environments. The flaw resides in the firewall's handling of network traffic validation mechanisms, particularly when processing specific types of packets that should be properly filtered or rejected.
The technical exploitation of this vulnerability occurs through two distinct attack vectors that leverage weaknesses in the packet processing logic. Attackers can craft DHCP discovery messages that appear legitimate to the firewall's validation system but contain malicious payload modifications designed to bypass the MAC-spoofing restrictions. Additionally, the vulnerability can be exploited through crafted non-IP traffic that exploits gaps in the firewall's protocol handling. Both attack methods target the underlying IPTables configuration that Neutron uses to enforce network security policies, effectively allowing unauthorized network access and traffic interception. This represents a fundamental breakdown in the principle of least privilege that should govern network access controls in virtualized environments.
The operational impact of CVE-2016-5363 extends beyond simple network disruption to encompass serious security implications that can compromise entire cloud deployments. Remote attackers who successfully exploit this vulnerability can cause denial of service conditions that disrupt legitimate network operations while simultaneously gaining the ability to intercept and potentially modify network traffic between virtual machines and external networks. The MAC-spoofing protection that should prevent unauthorized network access is effectively neutralized, allowing attackers to establish unauthorized communication channels and potentially escalate their privileges within the cloud infrastructure. This vulnerability directly violates the security principles outlined in the Common Weakness Enumeration standard CWE-284, which addresses improper access control mechanisms in network security implementations.
Organizations utilizing affected OpenStack Neutron versions face significant risk exposure that requires immediate remediation efforts to prevent potential security breaches. The vulnerability creates an attack surface that can be leveraged for advanced persistent threats, man-in-the-middle attacks, and network reconnaissance activities that can compromise sensitive data and cloud infrastructure integrity. Security teams must implement comprehensive monitoring and incident response procedures to detect exploitation attempts, while also prioritizing the upgrade to patched versions of Neutron that address the IPTables firewall implementation flaws. The remediation process should include verification of firewall rule sets and network segmentation policies to ensure that the underlying security controls remain effective against similar vulnerabilities that may exist in other components of the cloud infrastructure stack. This vulnerability highlights the critical importance of maintaining up-to-date security controls and proper network segmentation practices in cloud environments, as outlined in the ATT&CK framework's network ingress and egress tactics that emphasize the need for robust firewall and access control mechanisms.