TLS-DHE-DSS-WITH-DES-CBC-SHA Cipher Suite

Key Exchange Mechanism

Diffie Hellman Ephemeral - DHE

Grade - B

Diffie-Hellman Ephemeral (DHE) in cipher suites refers to a key exchange method where each session generates temporary, one-time-use (ephemeral) keys. This ensures forward secrecy, meaning if one session’s key is compromised, past and future sessions remain secure. DHE provides an added layer of protection against decryption by ensuring keys are used briefly and then discarded, enhancing security in TLS communications.

Authentication

Digital Signature Standard - DSS

Grade - C

Low usage

Cipher

Data Encryption Standard - DES

Grade - D

DES should not be used in cipher suites due to its weak 56-bit key size, making it highly vulnerable to brute-force attacks. Modern standards require stronger encryption, and DES’s vulnerabilities compromise security, making it unsuitable for protecting sensitive data in contemporary applications.

Hash

Secure Hash Algorithm - SHA

Grade - D

Chosen prefix attacks for SHA1 are feasible at an accessible cost to a well-funded adversary. This level of expense, while significant, does not pose a substantial barrier to attackers with sufficient resources, making such attacks a credible threat.

Cipher Mode

Cipher Block Chaining - CBC

Grade - D

Cipher Block Chaining (CBC) mode is vulnerable to the Lucky13 and POODLE (in TLS v1.2 and below) attacks. The Lucky13 attack exploits timing discrepancies in padding validation, allowing attackers to gradually reveal plaintext. The POODLE attack leverages padding errors to decrypt ciphertext by repeatedly modifying and sending it to the server, observing the error responses. These vulnerabilities arise from CBC’s handling of padding and error messages, making it less secure than modern encryption modes like Galois Counter Mode (GCM), which offer stronger integrity and confidentiality guarantees.