TLS-RSA-EXPORT-WITH-RC2-CBC-40-MD5 Cipher Suite

Key Exchange Mechanism

Rivest, Shamir, Adleman - RSA

Grade - B

RSA key exchange does not provide perfect forward secrecy because if an attacker captures the RSA private key, they can decrypt all past communications encrypted with the corresponding public key. This is due to the static nature of the key pairs used in RSA, which contrasts with protocols like Diffie-Hellman, where ephemeral keys ensure that past sessions remain secure even if current keys are compromised.

Authentication

Rivest, Shamir, Adleman - RSA

Grade - A

RSA as an authentication mechanism in cipher suites is secure because it relies on the difficulty of factoring large prime numbers. This makes it computationally infeasible for attackers to derive the private key from the public key, ensuring confidentiality and integrity in secure communications.

Cipher

Rivest Cipher 2 - RC2

Grade - D

Deprecated, vulnerable to low cost chosen-prefix attacks. These attacks allow an adversary to generate two different plaintexts that produce the same hash when encrypted. Due to its weak security, RC2 is no longer recommended for use in modern cryptographic applications.< a>.

Hash

Message Digest 5 - MD5

Grade - F

MD5 is considered highly insecure because chosen prefixes can be generated with minimal computing power. This vulnerability allows attackers to create different inputs that produce the same hash, leading to potential data breaches and integrity issues. Consequently, MD5 is unsuitable for modern cryptographic needs and should be avoided in favor of more secure algorithms.

Key Size

40 Bit - 40

Grade - F

A 40-bit cipher length is too short because it can be easily broken through brute-force attacks due to the limited number of possible keys (2^40). Modern computational power allows attackers to quickly try all potential keys, making 40-bit encryption insufficient for protecting sensitive data.

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.