SSL_­CK_­NULL_­WITH_­MD5

RSA (Rivest-Shamir-Adleman)

RSA^[443][444] key exchange is a key exchange^[133] that has no forward secrecy^{[127][128][129][130]}, and does not protect past sessions against future compromises. If long-term secret keys or passwords are compromised, encrypted communications and sessions recorded in the past can be retrieved and decrypted. Throughout its history RSA encryption has had many security flaws^{[445][446][447][448][449][450]} and was affected by variety of attack types: chosen-ciphertext attack^[55] (eg: Bleichenbacher's attack^[1][2], ROBOT attack^{[18][19][20][21]}), side-channel attack^[69][70][71] (eg: padding oracle attack^{[63][64][65][66]}, like Bleichenbacher's cat^[3][4][5][6]).

Always prefer cipher suites with PFS property over the non-PFS ones. Note that performance considerations implies preferring Ephemeral Elliptic-curve Diffie–Hellman^[432][433] over Ephemeral Diffie-Hellman^{[405][406][407][408]}.

RSA (Rivest-Shamir-Adleman)

Rivest–Shamir–Adleman^{[275][276][277]} is a digital signature^{[107][108][109][110]} algorithm, which is considered secure, however there are known weaknesses^{[278][279][280][281][282]}.

NULL

Encryption algorithm is a null encryption^[360][361] that cannot provide confidentiality^[91][92][93], so connection is available or disclosed to unauthorized individuals, entities, or processes.

Remove the cipher suite from the list of cipher suites supported by your server.

MD5 (Message Digest 5)

message authentication code^{[135][136][137][138]} is a hashed message authentication code^{[139][140][141][142][143][144][145]} which is considered secure^[456][457], despite the fact that the underlaying cryptographic hash function^{[94][95][96][97]} (MD5^{[197][198][199]}) is considered insecure^[200][201] as it vulnerable to collision attack^[57] in practice and to preimage attack^[67] in theory.

Leading client applications do not use this type of message authentication code^{[135][136][137][138]}. Unless your application or requirements specifically call for their use, it is generally safer to avoid cipher suites that are not adopted and supported by a critical mass of the industry. If your application or requirements specifically call for the use of a message authentication code^{[135][136][137][138]} that does not provide authenticated encryption^[74] prefer block cipher mode of operation^{[82][83][84][85][86]} (eg: counter with CBC-MAC^[32][33][34], Galois/Counter Mode^{[46][47][48][49]} or message authentication code^{[135][136][137][138]} (eg: Poly1305^[458][459]) that proved authenticated encryption over the ones which does not provide it. In case of a hashed message authentication code^{[139][140][141][142][143][144][145]} prefer message authentication code^{[135][136][137][138]} based on Secure Hash Algorithm 2^{[212][213][214]} over the ones based on MD5^{[197][198][199]}.