What it is
Summarises the target's TLS configuration from a cached SSL Labs scan: the overall grade, supported protocol versions, forward secrecy, HSTS, and a checklist of historical vulnerabilities including Heartbleed, POODLE, ROBOT, FREAK, LOGJAM and DROWN.
Why it matters
The grade compresses a great deal of judgement into a single letter, and the checklist underneath it is where the detail lives. The scan is cached, so a configuration change made recently may not show up yet.
Key terms
- Certificate Transparency
- Public logs of every certificate issued, so one issued by mistake or by an attacker gets noticed.
- SSL Labs Grade
- Qualys SSL Labs' overall rating of a server's HTTPS setup, from A+ down to F.
- Renegotiation
- Lets the browser and server agree new settings partway through a connection. Only the secure kind is safe.
- Fallback SCSV
- Stops attackers forcing a connection down to an older, weaker version of TLS.
- ChaCha20
- A cipher that runs faster than AES on phones and other devices without AES hardware.
- AEAD Ciphers
- Modern ciphers like AES-GCM and ChaCha20, which encrypt and check data in one step to avoid a whole class of attacks.
- CBC Ciphers
- An older cipher mode behind attacks like POODLE and Lucky 13.
- TLS Compression
- Compressing data before encrypting it, which the CRIME attack uses to steal cookies.
- Key Exchange Reuse
- Reusing the same temporary key exchange values across connections, which weakens forward secrecy.
- Weak DH Primes
- Widely shared Diffie-Hellman groups that are too small, so a well-funded attacker may already have broken them.
- Downgrade Attack
- Tricking a connection into using an older, weaker protocol or cipher, so it's easier to break.
- Padding Oracle
- A flaw where a server responds differently to badly padded data. By sending thousands of altered messages, attackers can use those replies to decrypt traffic.
- Heartbleed
- A bug in old OpenSSL versions that let anyone read server memory, including private keys and passwords.
- POODLE
- An attack on SSL 3.0 that decrypts data a byte at a time. Disabling SSL 3.0 fixes it.
- POODLE (TLS)
- A version of POODLE that works against TLS servers which don't check padding properly.
- Zombie POODLE
- A padding oracle in some servers that brings POODLE-style attacks back to CBC ciphers.
- GOLDENDOODLE
- A faster padding oracle attack on CBC ciphers, found in some firewalls and load balancers.
- Sleeping POODLE
- Another padding oracle on CBC ciphers, found in some network devices.
- FREAK
- Tricks a connection into using deliberately weak 1990s export encryption, which can be cracked in hours.
- Logjam
- Downgrades the key exchange to weak Diffie-Hellman groups that can be broken.
- DROWN
- Uses any server that still supports SSL 2.0 with the same key to decrypt modern TLS traffic.
- CCS Injection
- An OpenSSL bug (CVE-2014-0224) that lets an attacker force weak keys and read traffic.
- ROBOT
- A revived attack on RSA key exchange that can decrypt traffic, or sign messages with the server's key.
- Ticketbleed
- A bug in some F5 load balancers that leaks memory through TLS session tickets.