Why Strong Ciphers and Hardened SSL Settings Matter (and How to Get an A+ on SSL Labs)

If your site is running over HTTPS (which is should be), then your SSL/TLS configuration is doing more than just displaying the padlock in the browser to signify an element of trust. It’s protecting data, preventing attacks, and signaling trust to both users and search engines.

One of the easiest ways to benchmark your HTTPS configuration is by using the Qualys SSL Labs – SSL Testing Tool

This is a free tool which scans the SSL / TLS configuration and rates a site’s HTTP setup from an F to an A+.

What SSL Labs Tests (and Why It Matters)

The SSL Testing Tool performs a deep inspection of your HTTPS setup and evaluates a number of different areas:

• Certificate validity and chain
• Supported protocol versions
• Cipher strength
• Key exchange security
• Forward secrecy
• Security features, such as HSTS and OCSP stapling

An A+ rating signifies your configuration follows modern security best practices and protects against known vulnerabilities. A low rating would usually indicate old TLS versions are still enabled, weak cipher suites are still allowed, missing HSTS, or insecure renegotiation settings.

What is a Cipher Suite?

A cipher suite defines how your server encrypts traffic during a TLS connection. It typically includes a key exchange algorithm (eg. ECDHE), an encryption algorithm (eg. AES-GCM or CHACHA20) and a message authentication algorithm.

When someone visits your website, their browser and your server have to agree on how they’re going to encrypt the connection before any secure data is sent. This agreement is called a"TLS handshake".

During the TLS handshake, the browser sends a list of encryption methods (cipher suites) it supports. The server then looks at that list, and picks the strongest option that it also supports. Both the server and the browser then use that chosen cipher suite to encrypt the session.

Why This Matters

If your server allows weak cipher suites, and the browser also supports them, the connection could end up using much weaker encryption – even if stronger options are available. Weaker encryption algorithms (such as RC4 and 3DES) are known to have vulnerabilities.

What’s The Risk

Weak ciphers aren’t just a technical issue – or a trust signal – it can expose real user data and damage a website long term

• Traffic Can Be Decrypted: An attacker who intercepts encrypted traffic may be able to recover session cookies, read login credentials, and even extract personal or payment data from a website.
• Man-in-the-Middle (MITM) Attacks: An attacker can interfere with the TLS handshake and trick the browser or server into using a weaker cipher, exploiting known weaknesses in the cipher and making downgrade attacks possible.
• Loss of Forward Secrecy: If you’re using a static RSA key exchange instead of ECDHE and your private key is ever leaked, there is a risk of previously recorded encrypted traffic being decrypted. Stronger ciphers ensure old traffic remains secure.
• Compliance Failures: Weak ciphers can put you out of compliance with PCI-DSS (payment processing), ISO-27001 security policies, and many enterprise procurement requirements. In some industries, allowing TLS 1.0 is an automatic failure.

How to Ensure Strong Ciphers and Hardened SSL Settings

Disable Old Protocols

Most modern browsers only support TLS 1.2 and TLS 1.3, so all other protocols should be disabled. These include SSLv2, SSLv3, TLS 1.0 and 1.1. This ensures the removal of legacy cryptography, enforces forward secrecy, simplifies the handshake process and improves performance.

Enable Forward Secrecy

This ensures that even if your private key is compromised in the future, previously captured traffic cannot be decrypted. To enable this, make sure you’re using the ECDHE key exchange, and not the Static RSA key exchange.

The SSL Labs test gives a strong weight to this in it’s scoring model. You will likely score a D or F if this is not enabled.

Implement HSTS (Required for an A+ Score)

HSTS is the HTTP Strict Transport Security – it tells the browser to only connect to the site if it’s using HTTPS.

Before enabling this, you will need to make sure HTTPS is working – or your site will be inaccessible with this setting turned on.

Enable OCSP Stapling

Most modern servers support this by default, but the purpose is to improve performance and privacy when a browser verifies the certificate’s validity, to reduce the dependence on the certificate authorities’ servers.

Other Best Practices

• Certificates should use SHA-256 (not SHA-1)
• RSA keys are at least 2048-bit (or use ECDSA)
• The full certificate chain is installed correctly
• The certificate hasn’t expired

The Qualys SSL Labs – SSL Testing Tool should give clear indications of where your website succeeds or falls short in their numerous tests. These areas can be found within your cPanel/Plesk hosting, or there are various options if your site is routing through Cloudflare.

For specific questions, please feel free to contact me, or contact your hosting provider.