Cisco ACE 4710: BEAST Attack Protection

TL;DR

The BEAST attack exploits weaknesses in TLS 1.0 to decrypt HTTPS traffic. This guide shows you how to disable TLS 1.0 on your Cisco ACE 4710 load balancer, mitigating the risk of this vulnerability.

Steps to Mitigate BEAST on a Cisco ACE 4710

1. Access the ACE CLI: Connect to your Cisco ACE 4710 via SSH or console. You’ll need administrative privileges.
2. Enter Configuration Mode: Type the following command and press Enter:

   configure terminal

3. Disable TLS 1.0 Globally: This is the primary step to protect against BEAST. Use this command:

   no tls protocol all

4. Enable Supported TLS Versions (1.2 and 1.3 Recommended): After disabling ‘all’, explicitly enable the versions you want to support. TLS 1.2 is generally a good minimum, but consider 1.3 if your clients support it.

   tls protocol tls1.2

   tls protocol tls1.3

5. Verify the Configuration: Check that TLS 1.0 is no longer enabled and your desired versions are active:

   show tls protocol

   The output should *not* list TLS 1.0, but it *should* list TLS 1.2 and/or TLS 1.3 (if you enabled them).

6. Save the Configuration: Crucially, save your changes to persistent storage:

   write memory

7. Test Connectivity: After saving, thoroughly test your web applications and services to ensure they continue functioning correctly. Pay attention to any client compatibility issues.
   • Use a browser that supports TLS 1.2 or 1.3 for testing.
   • If older clients are affected, consider upgrading them or providing alternative access methods.

Important Considerations

• Client Compatibility: Disabling TLS 1.0 may break compatibility with very old browsers and applications. Plan accordingly.
• Regular Updates: Keep your ACE 4710 software up to date to benefit from the latest security patches and improvements.
• Monitor Logs: Regularly review your ACE 4710 logs for any connection errors or unusual activity after making these changes.