CVE-2025-54547 is a vulnerability identified in Arista Networks' DANZ Monitoring Fabric, a network monitoring and analytics solution widely used in data centers and enterprise networks. The issue arises when SSH session multiplexing is enabled on the client side. SSH multiplexing allows multiple SSH sessions (such as scp, sftp) to share a single TCP connection to improve efficiency. However, due to improper handling of session timeouts, multiplexed sessions can continue to perform file-system operations even after the configured session timeout has expired. This behavior violates expected session termination semantics, potentially allowing an attacker with low-level privileges to maintain unauthorized access to file operations beyond the intended session lifetime. The vulnerability is classified under CWE-613 (Insufficient Session Expiration), indicating a failure to properly expire sessions. The CVSS v3.1 base score is 5.3 (medium severity), reflecting local attack vector, low complexity, low privileges required, no user interaction, and partial impact on confidentiality, integrity, and availability. No patches or known exploits are currently available, but the vulnerability poses a risk of unauthorized file access or modification if exploited. Organizations using Arista DANZ Monitoring Fabric should assess their SSH multiplexing configurations and session timeout policies to mitigate potential risks.

For European organizations, the vulnerability could lead to unauthorized file access or modification on critical network monitoring infrastructure, potentially compromising sensitive network telemetry data or configuration files. This could degrade network visibility, impact incident response capabilities, or lead to data leakage. Since DANZ Monitoring Fabric is often deployed in large data centers and service provider environments, exploitation could affect network operations and security monitoring. The medium severity indicates a moderate risk, but the impact could be amplified in environments where strict session timeout enforcement is critical for compliance or security. Additionally, attackers with low privileges could leverage this flaw to escalate their access or persist longer in the environment. The lack of user interaction required makes automated exploitation feasible in targeted scenarios. European organizations with extensive Arista deployments in financial, telecommunications, or government sectors should be particularly vigilant due to the strategic importance of their network monitoring infrastructure.

Specific mitigations include: 1) Disabling SSH session multiplexing on clients connecting to Arista DANZ Monitoring Fabric devices until a patch is available. 2) Reviewing and tightening SSH session timeout configurations to ensure sessions are forcibly terminated as expected. 3) Implementing enhanced logging and monitoring of SSH session activities, focusing on file-system operations occurring after session timeouts. 4) Restricting SSH access to trusted hosts and users with strict privilege separation to minimize the risk of exploitation. 5) Applying network segmentation to isolate monitoring fabric devices from broader network access. 6) Engaging with Arista Networks support to obtain updates or patches addressing this vulnerability as soon as they are released. 7) Conducting regular audits of session management policies and verifying compliance with security best practices. These steps go beyond generic advice by focusing on the specific misuse of SSH multiplexing and session timeout weaknesses.