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Weak TLS_RSA_PSK_WITH_AES_128_CBC_SHA256
- IANA name:
- TLS_RSA_PSK_WITH_AES_128_CBC_SHA256
- OpenSSL name:
- RSA-PSK-AES128-CBC-SHA256
- GnuTLS name:
- TLS_RSA_PSK_AES_128_CBC_SHA256
- Hex code:
- 0x00, 0xB6
- TLS Version(s):
- TLS1.0, TLS1.1, TLS1.2, TLS1.3
- Protocol:
- Transport Layer Security (TLS)
- Key Exchange:
- Rivest Shamir Adleman algorithm (RSA)
- Authentication:
- Pre-Shared Key (PSK)
- Encryption:
- Advanced Encryption Standard with 128bit key in Cipher Block Chaining mode (AES 128 CBC)
- Hash:
- HMAC Secure Hash Algorithm 256 (SHA256)
- Included in RFC:
- Machine-readable:
- application/json
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.
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.