CVE-2024-12378 Overview
On affected platforms running Arista EOS with secure VXLAN configured, restarting the Tunnelsec agent will result in packets being sent over the secure VXLAN tunnels in the clear. This vulnerability represents a critical cleartext transmission issue (CWE-319) that can expose sensitive network traffic to unauthorized interception.
Critical Impact
Network traffic intended to be encrypted via secure VXLAN tunnels is transmitted in cleartext following a Tunnelsec agent restart, potentially exposing sensitive data to network-based attackers.
Affected Products
- Arista EOS platforms with secure VXLAN configured
- Systems utilizing the Tunnelsec agent for VXLAN encryption
Discovery Timeline
- 2025-05-08 - CVE CVE-2024-12378 published to NVD
- 2025-05-12 - Last updated in NVD database
Technical Details for CVE-2024-12378
Vulnerability Analysis
This vulnerability falls under CWE-319 (Cleartext Transmission of Sensitive Information). When the Tunnelsec agent is restarted on Arista EOS platforms with secure VXLAN configured, the encryption mechanism fails to properly reinitialize. This results in network packets that should traverse encrypted VXLAN tunnels being transmitted without encryption.
The issue is particularly concerning in data center environments where VXLAN is commonly deployed for network segmentation and multi-tenant isolation. Organizations relying on secure VXLAN for compliance with data protection requirements (such as PCI-DSS or HIPAA) could inadvertently expose protected data during or after Tunnelsec agent restarts.
Root Cause
The vulnerability stems from improper state management within the Tunnelsec agent during restart operations. When the agent is restarted, the encryption state is not properly preserved or reestablished before network traffic resumes, causing packets to be forwarded through VXLAN tunnels without the expected encryption layer applied.
Attack Vector
This vulnerability is exploitable via the network without requiring authentication or user interaction. An attacker positioned to capture network traffic (such as through network tap, compromised switch, or man-in-the-middle position) could intercept sensitive data during the window when packets are transmitted in cleartext.
The attack scenario involves:
- Monitoring network traffic on VXLAN tunnel paths
- Waiting for or triggering a Tunnelsec agent restart (through legitimate maintenance or other means)
- Capturing cleartext packets that should have been encrypted
- Extracting sensitive information from the captured traffic
Detection Methods for CVE-2024-12378
Indicators of Compromise
- Unencrypted VXLAN traffic observed where encryption should be active
- Tunnelsec agent restart events coinciding with cleartext traffic detection
- Network monitoring alerts for unencrypted sensitive data on VXLAN segments
- Anomalous traffic patterns following Tunnelsec agent service interruptions
Detection Strategies
- Deploy network traffic analysis tools to monitor for unencrypted packets on secure VXLAN tunnels
- Implement logging and alerting for all Tunnelsec agent restart events
- Configure deep packet inspection to detect cleartext transmission of sensitive protocols
- Monitor for discrepancies between expected encrypted traffic volume and actual encrypted traffic
Monitoring Recommendations
- Enable verbose logging for Tunnelsec agent state changes and restarts
- Configure SIEM correlation rules to alert on Tunnelsec restarts combined with network anomalies
- Implement continuous monitoring of VXLAN tunnel encryption status
- Deploy network sensors to detect cleartext traffic on segments expected to be encrypted
How to Mitigate CVE-2024-12378
Immediate Actions Required
- Review Arista security advisory for specific patch availability and affected versions
- Minimize Tunnelsec agent restarts until patches are applied
- Implement network monitoring to detect cleartext transmission events
- Consider temporary traffic diversion during planned maintenance windows involving Tunnelsec agent restarts
Patch Information
Arista has published Security Advisory #0113 addressing this vulnerability. Consult the Arista Security Advisory #0113 for specific patch versions and upgrade instructions applicable to your deployment.
Workarounds
- Schedule Tunnelsec agent restarts during low-traffic maintenance windows to minimize exposure
- Implement additional network-layer encryption (such as IPsec) as a defense-in-depth measure
- Deploy network access controls to limit potential attacker visibility into VXLAN traffic paths
- Monitor for cleartext traffic and immediately investigate any detected incidents
# Example: Monitor for Tunnelsec agent restarts on Arista EOS
# Check Tunnelsec agent status
show agent Tunnelsec logs
# Review recent agent restart events
show logging | include Tunnelsec
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
