Google Cloud PHP App Engine能否禁用弱加密套件DES-CBC3-SHA？

Unfortunately, right now, you can't directly customize or disable specific TLS cipher suites like DES-CBC3-SHA when running a PHP app on Google App Engine (GAE) with a custom domain. Here's why, and what you can do about it:

• GAE manages TLS termination at the frontend layer: TLS for GAE apps is handled by Google's global frontend infrastructure, not your individual app instances. For the standard environment (which includes PHP), Google doesn't expose any configuration options that let developers tweak the list of allowed cipher suites—this level of security setup is fully controlled and maintained by Google.
• This restriction applies across all GAE language stacks: The Java-related post you found isn't an exception; the same limitation holds for PHP and other languages. All standard environment language stacks share the same frontend TLS configuration, and developers don't have permissions to modify these low-level settings.
• Google does update its TLS policies over time: While you can't disable it manually, Google regularly updates its TLS configurations to align with security best practices. Older, less secure suites like DES-CBC3-SHA are likely candidates for removal in future updates. Keep an eye on Google Cloud's security announcements or App Engine release notes to stay informed about these kinds of changes.
• You can verify the current state yourself: To check if DES-CBC3-SHA is still supported for your domain, use tools like openssl or nmap. For example, run this command in your terminal:

  openssl s_client -connect your-custom-domain.com:443 -cipher DES-CBC3-SHA
  

  If the connection fails, that means the suite is already disabled. If it connects successfully, it's still part of the allowed list.

If meeting this security test requirement is non-negotiable, your best alternative right now is to set up a Cloud Load Balancer (CLB) in front of your GAE app. With CLB, you have full control over the TLS cipher suite list—you can explicitly disable DES-CBC3-SHA and configure exactly which suites you want to allow. This will require reconfiguring your traffic routing: point your custom domain to the CLB, and have the CLB forward requests to your GAE service.

内容的提问来源于stack exchange，提问作者NNN