CVE-2025-20210: Cisco Catalyst Center Auth Bypass Flaw

CVE-2025-20210 Overview

A vulnerability in the management API of Cisco Catalyst Center, formerly known as Cisco DNA Center, could allow an unauthenticated, remote attacker to read and modify the outgoing proxy configuration settings. This authentication bypass vulnerability (CWE-306: Missing Authentication for Critical Function) exists due to the lack of authentication in an API endpoint, enabling attackers to view or modify proxy configurations without requiring valid credentials.

Critical Impact

Successful exploitation allows attackers to view or modify outgoing proxy configuration, potentially disrupting internet traffic from Cisco Catalyst Center or enabling interception of outbound internet traffic.

Affected Products

• Cisco Catalyst Center (all vulnerable versions)
• Cisco DNA Center (legacy name for the same product)

Discovery Timeline

• 2025-05-07 - CVE-2025-20210 published to NVD
• 2025-08-13 - Last updated in NVD database

Technical Details for CVE-2025-20210

Vulnerability Analysis

This vulnerability represents a critical authentication bypass flaw in the Cisco Catalyst Center management API. The core issue stems from an API endpoint that fails to enforce authentication controls, allowing any remote attacker with network access to interact with sensitive proxy configuration functionality without presenting valid credentials.

The vulnerability enables two primary attack scenarios: reconnaissance through reading the current proxy configuration (information disclosure) and active exploitation through modifying the proxy settings. When an attacker modifies the outgoing proxy configuration, they can redirect all outbound internet traffic from the Catalyst Center through an attacker-controlled proxy server, enabling traffic interception, modification, or complete disruption of internet connectivity.

Root Cause

The root cause is classified under CWE-306: Missing Authentication for Critical Function. The affected API endpoint in the Cisco Catalyst Center management interface was implemented without proper authentication mechanisms. This design flaw allows unauthenticated requests to reach functionality that should be restricted to authenticated administrators only. The API endpoint responsible for proxy configuration management accepts and processes requests without validating the identity or authorization level of the requester.

Attack Vector

The attack vector is network-based, requiring the attacker to have network connectivity to the Cisco Catalyst Center management interface. Exploitation requires no user interaction, no prior authentication, and no elevated privileges. An attacker can craft HTTP requests targeting the vulnerable API endpoint to either retrieve the current proxy configuration or submit modified proxy settings.

The attack flow typically involves:

1. Attacker identifies a network-accessible Cisco Catalyst Center instance
2. Attacker sends unauthenticated API requests to the vulnerable endpoint
3. The API processes requests without authentication verification
4. Attacker can read current proxy settings or inject malicious proxy configuration
5. Modified proxy settings redirect outbound traffic through attacker infrastructure

For detailed technical information about this vulnerability, refer to the Cisco Security Advisory.

Detection Methods for CVE-2025-20210

Indicators of Compromise

• Unexpected changes to outgoing proxy configuration in Cisco Catalyst Center
• Unauthenticated API requests to the Catalyst Center management interface from unknown IP addresses
• Outbound traffic routing through unfamiliar proxy servers
• Network traffic anomalies indicating potential man-in-the-middle interception
• Audit log entries showing proxy configuration access or modifications without corresponding administrator activity

Detection Strategies

• Monitor Cisco Catalyst Center audit logs for unauthorized proxy configuration changes
• Implement network monitoring to detect unexpected API calls to the Catalyst Center management interface
• Deploy intrusion detection signatures for unauthenticated access attempts to Catalyst Center APIs
• Regularly audit proxy configuration settings against known-good baselines
• Alert on any outbound traffic destined for unknown or unauthorized proxy servers

Monitoring Recommendations

• Enable comprehensive logging on Cisco Catalyst Center management interfaces
• Configure SIEM alerts for proxy configuration modifications
• Implement network segmentation monitoring to detect lateral movement to management interfaces
• Establish baseline behavior for Catalyst Center API usage and alert on deviations
• Monitor for DNS queries or connections to suspicious proxy infrastructure

How to Mitigate CVE-2025-20210

Immediate Actions Required

• Apply the security patch from Cisco as soon as available for your version
• Restrict network access to the Cisco Catalyst Center management interface using firewall rules and ACLs
• Verify current proxy configuration settings and document any unauthorized changes
• Implement network segmentation to limit access to management interfaces
• Enable audit logging and monitor for suspicious API activity

Patch Information

Cisco has released security patches to address this vulnerability. Administrators should consult the Cisco Security Advisory cisco-sa-dnac-api-nBPZcJCM for specific version information and upgrade guidance. It is strongly recommended to upgrade to a fixed software release as the primary remediation strategy.

Workarounds

• Implement strict network access controls limiting connectivity to the Catalyst Center management interface to authorized administrators only
• Deploy firewall rules blocking external access to the management API endpoints
• Use VPN or jump server architecture for administrative access to reduce attack surface
• Monitor and audit all proxy configuration changes through alternative channels until patching is complete

# Example: Restrict management interface access via ACL (adjust for your environment)
# Limit access to Catalyst Center management to specific trusted networks
access-list CATALYST-MGMT-ACL permit ip 10.0.100.0 0.0.0.255 host 192.168.1.50
access-list CATALYST-MGMT-ACL deny ip any host 192.168.1.50 log