How to remediate – Cisco Prime Security Manager Web Detection

1. Introduction

Cisco Prime Security Manager Web Detection refers to the presence of a web-based management interface running on a system. This interface allows administrators to manage Cisco ASA CX devices, but its exposure to the internet can create an attack surface. Successful exploitation could allow attackers to gain control of the management tool and potentially compromise connected ASAs. Confidentiality, integrity, and availability may be impacted if exploited.

2. Technical Explanation

The vulnerability lies in the running of a web interface on the remote host that is intended for administrative access. An attacker with network access can attempt to exploit vulnerabilities within this web application. There are no known CVEs associated with simply *running* the web interface, but it represents an increased risk surface. A realistic example would be an attacker attempting to leverage default credentials or known exploits against the PRSM web server itself.

• Root cause: The web interface is enabled and accessible from a network.
• Exploit mechanism: An attacker attempts to access the web interface, potentially using brute-force attacks on default credentials or exploiting vulnerabilities in the web application code.
• Scope: Cisco Prime Security Manager (PRSM) software running on affected platforms.

3. Detection and Assessment

To confirm if a system is vulnerable, you can check for the presence of the PRSM web interface. A quick check involves verifying if port 80 or 443 are open and serving a Cisco Prime Security Manager login page. A thorough method would involve attempting to access the web interface from a remote location.

• Quick checks: Use `netstat -an | grep :80` or `netstat -an | grep :443` to check for listening ports.
• Scanning: Nessus plugin 16927 and OpenVAS scanner ID 95878 may identify the PRSM web interface. These are examples only.
• Logs and evidence: Check system logs for access attempts to port 80 or 443 related to PRSM.

netstat -an | grep :80

4. Solution / Remediation Steps

The recommended solution is to restrict access to the Cisco Prime Security Manager web interface, or disable it if not required. These steps aim to reduce the attack surface and protect against unauthorized access.

4.1 Preparation

• Ensure you have valid administrative credentials for the PRSM interface. A rollback plan involves restoring from the snapshot or backup.
• A change window may be required, depending on your organization’s policies.

4.2 Implementation

1. Step 1: Restrict access to the web interface using firewall rules, allowing only trusted IP addresses to connect.
2. Step 2: If the web interface is not required, disable it within the PRSM configuration settings.

4.3 Config or Code Example

Before

# No firewall rules restricting access to ports 80/443

After

# Firewall rule allowing only trusted IP addresses to connect to ports 80/443
iptables -A INPUT -p tcp --dport 80 -s  -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -s  -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP
iptables -A INPUT -p tcp --dport 443 -j DROP

4.4 Security Practices Relevant to This Vulnerability

Several security practices can help prevent this issue. Least privilege reduces the impact if exploited, and input validation blocks unsafe data. A strong patch cadence ensures timely updates for known vulnerabilities.

• Practice 1: Implement least privilege principles by restricting access to sensitive interfaces like PRSM’s web interface.
• Practice 2: Regularly review and update firewall rules to ensure only authorized traffic is allowed.

4.5 Automation (Optional)

# Example Ansible playbook to restrict access via firewall
- name: Restrict PRSM web interface access
  iptables:
    chain: INPUT
    protocol: tcp
    dport: "{{ item }}"
    jump: ACCEPT
    source: "{{ trusted_ip }}"
  with_items: [80, 443]
- name: Drop all other traffic to PRSM web interface
  iptables:
    chain: INPUT
    protocol: tcp
    dport: "{{ item }}"
    jump: DROP
  with_items: [80, 443]

5. Verification / Validation

To confirm the fix worked, verify that only trusted IP addresses can access the PRSM web interface. Re-run the earlier detection to show the issue is gone. A simple service smoke test involves confirming that legitimate administrative functions still work from a trusted source.

• Post-fix check: Use `netstat -an | grep :80` or `netstat -an | grep :443` and confirm only expected connections are present.
• Re-test: Attempt to access the web interface from an untrusted location; it should be blocked by the firewall.
• Smoke test: Log in to the PRSM interface from a trusted source and verify that you can perform basic administrative tasks.
• Monitoring: Monitor system logs for any unauthorized access attempts to ports 80 or 443.

netstat -an | grep :80

6. Preventive Measures and Monitoring

Update security baselines to include restrictions on web interface access. Add checks in CI/CD pipelines to prevent deployment of systems with open PRSM interfaces. Implement a sensible patch or config review cycle that fits the risk.

• Baselines: Update your security baseline to require firewall rules restricting access to sensitive interfaces like PRSM’s web interface.
• Pipelines: Add checks in CI/CD pipelines to scan for open ports and flag systems with exposed management interfaces.
• Asset and patch process: Review system configurations regularly to ensure compliance with security policies.

7. Risks, Side Effects, and Roll Back

Restricting access may inadvertently block legitimate administrative traffic if the trusted IP address changes. Disabling the web interface will require alternative management methods (e.g., CLI). Roll back involves restoring from the snapshot or backup.

• Risk or side effect 1: Blocking legitimate access; mitigate by carefully managing trusted IP addresses.
• Risk or side effect 2: Loss of web-based management; mitigate by ensuring alternative management methods are available.

8. References and Resources

• Vendor advisory or bulletin: https://www.cisco.com/c/en/us/products/security/prime-security-manager/index.html
• NVD or CVE entry: Not applicable for simply running the web interface.
• Product or platform documentation relevant to the fix: