Arista Networks EOS vulnerabilities

On affected platforms running Arista EOS with VRRPv2 IP Authentication Header (IP-AH) authentication configured, an unauthenticated attacker with access to the layer 2 network segment on which VRRP is running could bypass VRRP authentication and claim the virtual router master role, enabling the attacker to intercept, modify, or discard traffic that hosts on the segment send to the virtual gateway address.

On affected platforms running Arista EOS with Dynamic Host Configuration Protocol (DHCP) relay/snooping configured with the information option (Option 82), or with the DHCP server configured with match criteria based on the information option, an unauthenticated attacker connected to a client-facing VLAN(s) where the relay is configured can send a specially crafted packet that causes the DHCP Relay service to restart.

On affected platforms running Arista EOS, under certain circumstances plaintext shared secrets for configured Terminal Access Controller Access-Control System Plus (TACACS+) servers

On affected platforms running Arista EOS, under certain circumstances user passwordss may be written in clear text to log files during operations when specialized non-standard debugging trace levels are explicitly enabled. To exploit these vulnerabilities, a malicious actor must already possess authenticated local administrative access to the device shell, and specialized non-standard debugging trace levels must be explicitly enabled. This issue was discovered internally by Arista, and the company is not aware of any malicious exploitation of this vulnerability in customer networks.

On affected platforms running Arista EOS, under certain circumstances plaintext private keys may be written in clear text to log files during operations when specialized non-standard debugging trace levels are explicitly enabled. To exploit these vulnerabilities, a malicious actor must already possess authenticated local administrative access to the device shell, and specialized non-standard debugging trace levels must be explicitly enabled. This issue was discovered internally by Arista, and the company is not aware of any malicious exploitation of this vulnerability in customer networks.

On affected platforms running Arista EOS with dual switch cards and with ingress Security ACLs configured on Switched Virtual Interfaces (SVI) in shared mode, restarting of the secondary switchcard forwarding agent or insertion of secondary switchcard, can cause security ACLs on shared SVIs to stop functioning. This may result in incorrect packet permit/deny behavior. This issue was discovered internally by Arista, and the company is not aware of any malicious exploitation of this vulnerability in customer networks.

On affected platforms running Arista EOS with password authentication configured, a specially crafted password can create orphan authentication sessions. Repeated exploitation of this issue can exhaust available authentication resources, resulting in legitimate users being unable to log in to the device. This issue was discovered internally by Arista, and the company is not aware of any malicious exploitation of this vulnerability in customer networks.

On affected platforms running Arista EOS with both 802.1X port authentication and the RADIUS proxy feature configured with dynamic authorization, a low-privileged attacker on an adjacent network segment who induces a RADIUS packet through a configured RADIUS proxy client can prevent RADIUS dynamic authorization messages, including Change-of-Authorization (CoA) and Disconnect-Requests as defined in RFC 5176, from being applied to locally authenticated 802.1X sessions. This allows an endpoint session that a RADIUS server or network access control system has ordered disconnected to remain authorized on the network. Both 802.1X port authentication with dynamic authorization and RADIUS proxy with dynamic authorization must be explicitly configured for a deployment to be exposed to this issue. This issue was discovered internally by Arista, and the company is not aware of any malicious exploitation of this vulnerability in customer networks.

On affected platforms with hardware IPSec support running Arista EOS with certain IPsec features enabled, EOS may exhibit unexpected behavior in specific cases. Physical interface flaps and certain agent restarts can cause IPsec tunnel re-establishment with existing Security Associations, resulting in sequence number mismatches between tunnel endpoints potentially causing unstable communication.

On affected platforms running Arista EOS where a tunnel decapsulation configuration—such as VXLAN (Virtual Extensible LAN), decap-groups, or a GRE (Generic Routing Encapsulation) tunnel interface—is present, the switch will incorrectly decapsulate and forward other unexpected tunneled packet with a destination IP matching its configured decapsulation IP. This occurs because the switch does not verify the tunnel protocol type, potentially leading to the unexpected processing of non-configured tunnel traffic. This issue has been reported as being exploited in the wild.

On affected platforms running Arista EOS with MACsec and egress ACLs configured on the same interfaces, the ACL policies may not be enforced for packets egressing on those ports. This can cause outgoing packets to incorrectly be allowed or denied.

On affected platforms running Arista EOS with 802.1x authentication configured on the access/trunk ports, and routing enabled on the access VLAN of the ports, a malicious supplicant may be able to bypass the requirement to perform 802.1x authentication.

In Arista’s EOS when in 802.1X mode, multi-auth unauthenticated hosts might be allowed access to a switch port if there exists an EAPOL capable device in the fallback VLAN.

On affected platforms running Arista EOS with MACsec configuration, a specially crafted packet can cause the MACsec process to terminate unexpectedly. Continuous receipt of these packets with certain MACsec configurations can cause longer term disruption of dataplane traffic.