How to remediate – VMware VRealize Operations Manager 6.x Oracle JRE JMX Deserial…

1. Introduction

VMware vRealize Operations Manager 6.x is affected by a remote code execution vulnerability in the Oracle JRE JMX component. This allows an attacker to run commands on vulnerable systems without needing valid credentials. Systems running non-appliance versions of vROps are at risk, potentially leading to loss of confidentiality, integrity and availability of data and services.

2. Technical Explanation

The vulnerability is caused by a flaw in how vRealize Operations Manager 6.x deserializes authentication credentials within the Oracle JRE JMX component. An unauthenticated remote attacker can send specially crafted requests to exploit this, leading to arbitrary code execution on the host system. The CVE associated with this issue is CVE-2016-3427.

• Root cause: Insecure deserialization of authentication credentials in the JMX component.
• Exploit mechanism: An attacker sends a malicious serialized object to the vROps server, which triggers code execution during deserialization.
• Scope: Non-appliance versions of VMware vRealize Operations Manager 6.x are affected.

3. Detection and Assessment

You can confirm if your system is vulnerable by checking the version of vRealize Operations Manager installed, and confirming it’s a non-appliance deployment. Scanning tools may also identify this vulnerability.

• Quick checks: Check the vROps UI for the product version.
• Scanning: Nessus plugin ID 98647 or Rapid7 InsightVM vulnerability ID CVE-2016-3427 can be used as examples to detect this issue.
• Logs and evidence: Review vROps logs for any suspicious activity related to JMX connections, although direct log evidence may not be readily available without enabling verbose logging.

# No specific command is available to directly confirm vulnerability exposure. Check the UI version.

4. Solution / Remediation Steps

The solution involves blocking the appropriate ports as per the vendor advisory.

4.1 Preparation

• Ensure you have a rollback plan in place, which involves restoring from the pre-change snapshot/backup and restarting the vROps service.
• A change window may be needed depending on your environment’s maintenance schedule. Approval should be sought from relevant IT teams.

4.2 Implementation

1. Step 1: Block incoming TCP traffic to ports 5985 and 6311 on the vRealize Operations Manager server using a firewall or network access control list.

4.3 Config or Code Example

Before

# No specific config example available, as this is a firewall rule change. Ports 5985 & 6311 are open by default.

After

# Firewall rule blocking incoming TCP traffic on ports 5985 and 6311. Example using iptables:
iptables -A INPUT -p tcp --dport 5985 -j DROP
iptables -A INPUT -p tcp --dport 6311 -j DROP

4.4 Security Practices Relevant to This Vulnerability

Several security practices can help prevent this type of issue.

• Practice 1: Least privilege – restrict access to services and ports only to those who need it, reducing the attack surface.
• Practice 2: Network segmentation – isolate critical systems like vROps on a separate network segment to limit the impact of potential breaches.

4.5 Automation (Optional)

# Example Ansible playbook to block ports on remote hosts:
---
- hosts: vrops_servers
  become: true
  tasks:
    - name: Block JMX ports
      iptables:
        chain: INPUT
        protocol: tcp
        destination_port: '5985,6311'
        jump: DROP

5. Verification / Validation

Confirm the fix by checking that the JMX ports are blocked and verifying vROps functionality.

• Post-fix check: Use `netstat -tulnp | grep 5985` or `netstat -tulnp | grep 6311`. The output should not show any processes listening on these ports.
• Re-test: Re-run the earlier port scan to confirm that ports 5985 and 6311 are no longer accessible.
• Smoke test: Verify you can still log into the vROps UI and access key monitoring dashboards.
• Monitoring: Monitor firewall logs for any blocked connections on ports 5985 and 6311 as an example of regression detection.

# Example output after blocking ports (no listening processes):
# netstat -tulnp | grep 5985
# (No output)

6. Preventive Measures and Monitoring

Update security baselines to include port restrictions, and add checks in your CI/CD pipeline.

• Baselines: Update your server hardening baseline or CIS benchmark to explicitly block incoming traffic on ports 5985 and 6311.
• Pipelines: Integrate vulnerability scanning into your CI/CD pipeline to identify similar issues during development and deployment.
• Asset and patch process: Implement a regular patch review cycle for all systems, including vRealize Operations Manager, to address known vulnerabilities promptly.

7. Risks, Side Effects, and Roll Back

Blocking ports may disrupt legitimate JMX connections if they are in use. Restore from the pre-change snapshot/backup to roll back.

• Risk or side effect 1: Blocking ports could impact other services relying on JMX. Monitor for unexpected service disruptions.
• Roll back:
  1. Step 1: Remove the firewall rules blocking ports 5985 and 6311.
  2. Step 2: Restore from the pre-change snapshot/backup if necessary.
  3. Step 3: Restart the vROps service.

8. References and Resources

• Vendor advisory or bulletin: https://www.vmware.com/security/advisories/VMSA-2016-0005.html
• NVD or CVE entry: CVE-2016-3427
• Product or platform documentation relevant to the fix: No specific documentation available beyond the vendor advisory.