Back to scan results
Check 27 of 45

Advanced SSL/TLS Vulnerability Testing

We send narrowly targeted TLS ClientHello messages to discover whether the server will select protocol, cipher, compression, and key-exchange capabilities associated with well-known TLS attacks. Each connection stops after ServerHello, before keys or application data are exchanged.

What this check probes

  • POODLE — whether SSL 3.0 completes ServerHello.
  • BEAST-era exposure — whether TLS 1.0 selects a CBC cipher.
  • SWEET32 — whether the server accepts a 3DES suite.
  • RC4 — whether any targeted RC4 suite is selected.
  • FREAK-class downgrade risk — whether an old EXPORT cipher is selected.
  • NULL encryption — whether a cipher providing authentication but no confidentiality is accepted.
  • CRIME — whether TLS-level DEFLATE compression is selected.
  • Forward secrecy — static RSA key exchange is a warning because it lacks forward secrecy and is a prerequisite for ROBOT-class attacks.
  • Secure renegotiation — a modern TLS 1.2 ServerHello should signal RFC 5746 renegotiation support.

The strong baseline offers ECDHE/DHE with AES-GCM or ChaCha20-Poly1305. A ServerHello proves that the selected capability is enabled; a rejected targeted offer is not treated as a vulnerability.

This check does not send malformed heartbeat records or RSA ciphertexts, so it does not claim to exploit or rule out Heartbleed or a ROBOT padding oracle. It also does not exchange application data.

Why this matters for PCI DSS

PCI DSS requires strong cryptography whenever account data crosses open or public networks. Keeping obsolete protocols or cipher suites enabled expands the downgrade surface even when modern browsers normally negotiate something stronger.

This check complements the basic protocol-version and certificate checks. A pass means the targeted weak capabilities were rejected; it is not a complete cryptographic assessment of every virtual host, non-HTTPS TLS service, TLS 1.3 implementation, or server library.

How to fix it

Use TLS 1.2 and TLS 1.3 only. Remove SSL, TLS 1.0, and TLS 1.1. Disable RC4, DES/3DES, EXPORT, NULL, static-RSA, and TLS-compression capabilities. Prefer ECDHE with AES-GCM or ChaCha20-Poly1305.

nginx:

ssl_protocols TLSv1.2 TLSv1.3;
ssl_ciphers ECDHE+AESGCM:ECDHE+CHACHA20:DHE+AESGCM;
ssl_prefer_server_ciphers off;

Apache:

SSLProtocol -all +TLSv1.2 +TLSv1.3
SSLCipherSuite ECDHE+AESGCM:ECDHE+CHACHA20:DHE+AESGCM
SSLCompression off

IIS / Windows Server: disable obsolete SCHANNEL protocols and cipher suites through Group Policy or the SCHANNEL registry settings, then reboot. IIS Crypto's “Best Practices” template can provide a starting point, but confirm application compatibility and re-scan after applying it.

Update the operating system and TLS library as well as the web-server configuration. Cipher settings cannot compensate for an unpatched cryptographic implementation.

Fixed it? Re-run the scan to confirm.

Run scan again