CVE-2024-9448 in EOS
Summary
by MITRE • 05/08/2025
On affected platforms running Arista EOS with Traffic Policies configured the vulnerability will cause received untagged packets not to hit Traffic Policy rules that they are expected to hit. If the rule was to drop the packet, the packet will not be dropped and instead will be forwarded as if the rule was not in place. This could lead to packets being delivered to unexpected destinations.
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Analysis
by VulDB Data Team • 08/26/2025
This vulnerability exists within Arista EOS networking platforms where traffic policies are configured, specifically affecting how untagged packets are processed within the forwarding plane. The flaw manifests when the system fails to properly match incoming untagged packets against configured traffic policy rules, creating a bypass condition that allows packets to circumvent intended network controls. The vulnerability impacts the fundamental packet processing logic where the system should enforce policy decisions but instead permits traffic to flow through without proper inspection or filtering. This represents a critical failure in the network security enforcement mechanisms that organizations rely upon to maintain control over their network traffic flows.
The technical root cause stems from improper handling of untagged packet classification within the traffic policy evaluation engine. When packets arrive without vlan tags, the system's packet matching algorithm fails to correctly associate them with the appropriate policy rules that should govern their disposition. This misconfiguration allows packets to bypass the intended traffic policy enforcement points, effectively creating a pathway for traffic to flow outside the expected security boundaries. The flaw operates at the data plane level where packet forwarding decisions are made, making it particularly dangerous as it can affect all traffic passing through the affected network infrastructure. The vulnerability aligns with CWE-284 Access Control Bypass, as it allows unauthorized traffic flow that should have been restricted by policy rules.
The operational impact of this vulnerability is significant for network security posture and compliance. Organizations that rely on traffic policies for access control, traffic shaping, or security enforcement may experience unauthorized traffic delivery to unexpected destinations, potentially exposing sensitive network segments to unintended access. The vulnerability could enable attackers to bypass network controls that were designed to prevent specific traffic patterns or destination access, creating potential ingress points for malicious activity. Network administrators may observe unexpected traffic flows or performance issues that they cannot immediately attribute to policy enforcement failures, complicating incident response and forensic analysis. This vulnerability directly impacts the principle of least privilege by allowing traffic to bypass intended restrictions, potentially leading to information disclosure or unauthorized access to network resources.
Mitigation strategies should focus on immediate platform updates and configuration reviews to address the traffic policy evaluation logic. Organizations should implement comprehensive traffic policy testing procedures to validate that all packet types, including untagged traffic, are properly matched against intended rules. Network segmentation and redundant security controls should be implemented as compensating measures while awaiting official patches from Arista. Monitoring and alerting systems should be enhanced to detect unusual traffic patterns that might indicate policy bypasses. The vulnerability demonstrates the importance of thorough testing for network security controls, particularly around packet classification and policy enforcement mechanisms. Security teams should conduct immediate risk assessments to identify affected network segments and implement temporary controls such as redundant firewall rules or access control lists to protect against the potential exploitation of this vulnerability.