Weak Cipher Suite

IANA name:

TLS_KRB5_WITH_3DES_EDE_CBC_SHA

Hex code:

0x00, 0x1F

TLS Version(s):

TLS1.0, TLS1.1

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Protocol:

Transport Layer Security (TLS)

Key Exchange:

Kerberos 5 (KRB5)

Non-ephemeral Key Exchange:

This key exchange algorithm does not support Perfect Forward Secrecy (PFS) which is recommended, so attackers cannot decrypt the complete communication stream.

Authentication:

Kerberos 5 (KRB5)

Encryption:

Triple-DES (Encrypt Decrypt Encrypt) in Cipher Block Chaining mode (3DES EDE CBC)

Cipher Block Chaining:

In 2013, researchers demonstrated a timing attack against several TLS implementations using the CBC encryption algorithm (see isg.rhul.ac.uk). Additionally, the CBC mode is vulnerable to plain-text attacks in TLS 1.0, SSL 3.0 and lower. A fix has been introduced with TLS 1.2 in form of the GCM mode which is not vulnerable to the BEAST attack. GCM should be preferred over CBC.

Triple-DES:

While Triple-DES is still recognized as a secure symmetric-key encryption, a more and more standardizations bodies and projects decide to deprecate this algorithm. Though not broken, it has been proven to suffer from several vulnerabilities in the past (see sweet32.info).

Hash:

HMAC Secure Hash Algorithm 1 (SHA)

Secure Hash Algorithm 1:

The Secure Hash Algorithm 1 has been proven to be insecure as of 2017 (see shattered.io).

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Included in RFC:

• RFC 2712

Machine-readable:

application/json