How We Solved Weak Cipher Issues in Our API Gateway Using CloudFront

Hey Folks i recently had this issue in my prodcution setup where the security audit team came up with number of weak ciphers in our API endpoints exposed to public.

And i checked myself running some nmap and SSL labs tools and yeah found that our AWS API gateway served with Internal CDN has this bottle neck of not being able to select TLS.1.2-2021.

So just did a brain storming session and came with 2 solutions .

1. Creating cloudfront distribution infront of API gateway so that we can have TLS.1.2_2021 and resolve the weak ciphers.
2. Introducing cloudfare or similar network security solution.

I tested both of them resolves our issue, for now i have selected option 1 since i want to go with AWS solution.Cool lets jump on to the solution what i have worked on .

The Problem in Detail
Our original setup was relatively simple:

Internal CDN content was served via an AWS API Gateway.
It worked well functionally, but the TLS configuration behind the scenes was using cipher suites considered weak or outdated by modern security standards.
These cipher suites could make our endpoints susceptible to downgrade attacks or eavesdropping — and that’s not acceptable for any service, internal or external.

We needed a solution that:

Gave us control over TLS policies,
Didn’t require major rearchitecture,
Could be deployed quickly and verified with minimal disruption.
The Solution: Wrap It with CloudFront
After evaluating options, we landed on this: place CloudFront in front of API Gateway.

CloudFront allows you to:

Enforce strict TLS policies and cipher suite selection
Redirect HTTP to HTTPS
Cache and accelerate responses globally
Add a security layer with AWS Shield and WAF
By setting CloudFront to use the TLSv1.2_2021 policy, we could ensure that only strong, modern ciphers were allowed. Plus, we got the added bonus of better caching and performance.

Here’s how the architecture changed:

Resolving Weak Cipher Vulnerability

Before:
User → API Gateway (Weak TLS)

After:
User → CloudFront (TLS 1.2_2021) → API Gateway

Step-by-Step Implementation

1. Keep Your Existing API Gateway
   We didn’t touch the routes or backend logic in API Gateway. It remained the origin server in our setup.

2. Create a CloudFront Distribution
   Key configuration settings:

Origin Domain Name: API Gateway endpoint.
Origin Protocol Policy: Set to HTTPS Only to ensure secure backend traffic.
Viewer Protocol Policy: Set to Redirect HTTP to HTTPS to enforce encrypted traffic from users.
Security Policy: This is the critical part — use TLSv1.2_2021, which includes strong, modern cipher suites.
Caching: Customized based on TTLs, headers, and query strings. We kept cache invalidation in mind for future updates.
Compression: Enabled automatic compression for performance.

1. Test and Validate We validated the new setup from multiple angles:

Cipher suite validation: Used nmap and online SSL test tools to confirm the correct ciphers were enforced.
Functional regression: Ensured that all API features continued working.
Performance benchmarking: Compared latency before and after CloudFront. We saw improvements due to edge caching.
Benefits Gained
Security Fix Applied: The primary issue — weak TLS ciphers — was resolved with no impact to core services.
Better Global Performance: CloudFront’s edge nodes improved response time for users across regions.
Simplified Security Management: TLS enforcement, protocol redirection, and caching were all handled in one place.
Additional Protection: With AWS Shield and optional WAF, CloudFront added another layer of security.
Lessons Learned
CloudFront is powerful, but complex: There are lots of settings — especially for caching, TTLs, and behaviors — that you need to get right.
Cost is a factor: CloudFront isn’t free, especially if you serve large volumes of traffic. But the trade-off for security and performance was worth it.
Plan your cache invalidation: Without a good strategy, you might serve stale content, especially in dynamic applications.
Final Thoughts
In the end, introducing CloudFront in front of our API Gateway gave us full control over TLS settings and eliminated the weak cipher issue. We got better performance and a stronger security posture — all without rewriting any of our backend code.

If you’re in a similar position — working with API Gateway and facing cipher or TLS limitations — I’d highly recommend looking at CloudFront as a front-door layer. It’s more than just a CDN; it’s a security and performance powerhouse when configured right.

We’re also exploring the use of CloudFront Functions and Lambda@Edge for further customization. I’ll cover that in a future post.

Let me know if you’ve faced a similar issue or tried a different solution — I’d love to hear what worked for you.

I am also planning to to implement cloudfare in near future as a single layer Security for WAF-Antiddos and CDN that will also work well as i have already tested it .