1. Introduction
VMware Cloud Director Authentication Bypass (VMSA-2023-0026) is a security flaw in VMware’s cloud management platform. It allows an attacker to bypass login restrictions on the appliance under specific conditions, potentially gaining unauthorised access. This affects systems running VMware Cloud Director Appliance and could lead to compromise of confidentiality, integrity, and availability of virtualised workloads.
2. Technical Explanation
- Exploit mechanism: An attacker with network access to the appliance can connect via SSH or the management console and bypass login prompts, gaining shell or administrative access. For example, connecting to port 22 might allow immediate access without a password if the system is vulnerable.
- Scope: VMware Cloud Director Appliance upgraded to version 10.5 from an older release.
3. Detection and Assessment
- Quick checks: Use the command line interface to display the VMware Cloud Director Appliance version:
vcd-cli about - Scanning: Nessus has not tested for this issue directly, relying on self-reported version numbers. Consider using other vulnerability scanners and checking their coverage of VMSA-2023-0026.
vcd-cli about4. Solution / Remediation Steps
The fix involves following VMware’s recommended steps in their security advisory.
4.1 Preparation
- Ensure you have access to the vendor advisory and understand the upgrade process. A roll back plan involves restoring from the pre-upgrade backup.
- A change window may be required, depending on service impact. Approval from the system owner is recommended.
4.2 Implementation
- Step 1: Refer to https://www.vmware.com/security/advisories/VMSA-2023-0026.html for detailed upgrade instructions.
- Step 2: Follow the steps to apply the recommended patch or update, ensuring a successful installation without errors.
4.3 Config or Code Example
Before
After
4.4 Security Practices Relevant to This Vulnerability
Practices that help prevent similar issues include least privilege and a robust patch cadence.
- Practice 1: Least privilege reduces the impact if an attacker gains access, limiting their ability to compromise other systems.
- Practice 2: A regular patch cadence ensures timely application of security updates, mitigating known vulnerabilities like this one.
4.5 Automation (Optional)
5. Verification / Validation
- Post-fix check: Run
vcd-cli aboutto confirm the upgraded version is installed. - Re-test: Attempt to connect via SSH (port 22) without credentials; authentication should be required.
- Smoke test: Verify users can log in to the VCD provider and tenant login portal on port 443 as normal.
- Monitoring: Monitor appliance logs for failed login attempts, indicating potential attacks.
vcd-cli about6. Preventive Measures and Monitoring
Update security baselines to include the latest VMware Cloud Director Appliance versions. Implement regular vulnerability scanning in CI/CD pipelines.
- Baselines: Update your security baseline or policy to reflect the minimum supported version of VMware Cloud Director Appliance.
- Pipelines: Add checks during deployment to verify the appliance version meets security requirements.
- Asset and patch process: Review and update your asset inventory and patch management process to ensure timely application of security updates.
7. Risks, Side Effects, and Roll Back
Upgrading can introduce compatibility issues or service downtime. A roll back plan is essential.
- Risk or side effect 1: Upgrade may cause temporary service disruption. Mitigate by scheduling during a maintenance window.
- Roll back: Restore the VMware Cloud Director Appliance from the pre-upgrade backup if the upgrade fails or causes unacceptable service disruption.
8. References and Resources
- Vendor advisory or bulletin: https://www.vmware.com/security/advisories/VMSA-2023-0026.html
- NVD or CVE entry: CVE-2023-34060
- Product or platform documentation relevant to the fix: https://kb.vmware.com/s/article/88176