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Weak TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA
- IANA name:
- TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA
- OpenSSL name:
- ECDHE-ECDSA-AES256-SHA
- GnuTLS name:
- TLS_ECDHE_ECDSA_AES_256_CBC_SHA1
- Hex code:
- 0xC0, 0x0A
- TLS Version(s):
- TLS1.0, TLS1.1, TLS1.2, TLS1.3
- Protocol:
- Transport Layer Security (TLS)
- Key Exchange:
- PFS Elliptic Curve Diffie-Hellman Ephemeral (ECDHE)
- Authentication:
- Elliptic Curve Digital Signature Algorithm (ECDSA)
- Encryption:
- Advanced Encryption Standard with 256bit key in Cipher Block Chaining mode (AES 256 CBC)
- Hash:
- HMAC Secure Hash Algorithm 1 (SHA)
- Included in RFC:
- Machine-readable:
- application/json
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.
Secure Hash Algorithm 1:
The Secure Hash Algorithm 1 has been proven to be insecure as of 2017 (see shattered.io).