Knowledge Base

F

Cipher Suite: TLS_­DH_­anon_­EXPORT_­WITH_­DES40_­CBC_­SHA

Summary

code:
(0x00, 0x19)
IANA Name:
TLS_DH_anon_EXPORT_WITH_DES40_CBC_SHA

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Components

F
Key Exchange Method
Name
Anonymous Diffie–Hellman (ADH)
Security
The anonymous Diffie-Hellman[90] key exchange[467] is a variant of Diffie-Hellman[269][270][271][272][273] key exchange that does not provide authenticity[201][202][203]. Lack of authentication causes that the identity of server cannot be proved, so connection is open for a man-in-the-middle attack[414].
Recommendations
Remove the cipher suite from the list of cipher suites supported by your server or replace the cipher suite with it's Ephemeral Diffie-Hellman[142][143][144][145] version.
F
Authentication Method
Name
anon
Security
Lack of authentication is combined with anonymous key exchange[25][26], identity of server cannot be proved, so connection is open for a man-in-the-middle attack[414].
Recommendations
Remove the cipher suite from the list of cipher suites supported by your server.
F
Encryption Type
Name
DES-40
Security
Encryption algorithm Data Encryption Standard[96][97][98][99][100] is considered obsolete[400][401][402][403][404][405]. It is weakened against brute-force attack[555]. It cannot provide confidentiality[198][199][200], so connection is available or disclosed to unauthorized individuals, entities, or processes.
Recommendations
Remove the cipher suite from the list of cipher suites supported by your server.
B
Encryption Mode
Name
Cipher Block Chaining (CBC)
Security
Encryption mode is cipher block chaining[132][133][134]. It is vulnerable[103] to timing attack[479] (eg: Lucky Thirteen attack[331][332]) and padding oracle attack[45][46][47][48] (eg: POODLE attack[362][363][364]).
Recommendations
Remove the cipher suite from the list of cipher suites supported by your server or at least set the cipher suite order explicitly and any cipher suite modes be preferred over ciphers suites with CBC modes.
D
Encryption Key Size
Name
40
Security
Any symmetric key[193][194][195] with key size[438] less than 128 bits are disallowed by National Institute of Standards and Technology[428][429] as it is vulnerable to preimage attack[215] in theory. It cannot reliably prove that message came from the stated sender (its authenticity) and has not been changed, so connection is open for a man-in-the-middle attack[414].
Recommendations
Remove the cipher suite from the list of cipher suites supported by your server.
C
Encryption Block Size
Name
64
Security
Any block cipher[524][525][526][527] uses a block size[409] of 64 bits is vulnerable to sweet32 attack[496][497][498][499].
Recommendations
Remove the cipher suite from the list of cipher suites supported by your server, or setup yout server to enforce changing session key regularly (rekeying[567]).
A-
Message Authentication Code
Name
SHA-1
Security
message authentication code[128][129][130][131] is a hashed message authentication code[418][419][420][421][422][423][424] which is considered secure[159], despite the fact that the underlayingcryptographic hash function[510][511][512][513] (Secure Hash Algorithm 1[204][205][206]) is considered insecure[370][371][372][373][374][375][376].
Recommendations
If your application or requirements specifically call for the use of a message authentication code[128][129][130][131] that does not provide authenticated encryption[563] prefer block cipher mode of operation[293][294][295][296][297] (eg: counter with CBC-MAC[266][267][268], Galois/Counter Mode[65][66][67][68] or message authentication code[128][129][130][131] (eg: Poly1305[289][290]) that proved authenticated encryption over the ones which does not provide it. In case of a hashed message authentication code[418][419][420][421][422][423][424] prefer message authentication code[128][129][130][131] based on Secure Hash Algorithm 2[71][72][73] over the ones based on Secure Hash Algorithm 1[204][205][206].