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Security in MySQL  /  Using Encrypted Connections  /  Encrypted Connection TLS Protocols and Ciphers

5.2 Encrypted Connection TLS Protocols and Ciphers

MySQL supports TLS encryption, and enables configuring which ciphers to permit for encrypted connections. It is also possible to determine which TLS protocol and cipher the current session uses.

Supported Connection TLS Protocols

MySQL supports encrypted connections using the TLSv1 protocol. As of MySQL 5.5.42, SSL 2.0 and SSL 3.0 are explicitly disabled because they provide weak encryption.

Connection Cipher Configuration

A default set of ciphers applies to encrypted connections, which can be overridden by explicitly configuring the permitted ciphers. During connection establishment, both sides of a connection must permit some cipher in common or the connection fails. Of the permitted ciphers common to both sides, the SSL library chooses the one supported by the provided certificate that has the highest priority.

To specify a cipher or ciphers for encrypted connections, use the --ssl-cipher option, which is available for the server and for client programs.

For master/slave replication, the MASTER_SSL_CIPHER option for the CHANGE MASTER TO statement specifies which ciphers a slave server permits for connections to the master.

To determine which ciphers a given server supports, check the session value of the Ssl_cipher_list status variable:

SHOW SESSION STATUS LIKE 'Ssl_cipher_list';

The Ssl_cipher_list status variable lists the possible SSL ciphers (empty for non-SSL connections). The set of available ciphers depends on your MySQL version and whether MySQL was compiled using OpenSSL or yaSSL, and (for OpenSSL) the library version used to compile MySQL.

MySQL passes a default cipher list to the SSL library.

MySQL passes this default cipher list to OpenSSL:

AES256-GCM-SHA384
AES256-SHA
AES256-SHA256
CAMELLIA256-SHA
DES-CBC3-SHA
DHE-DSS-AES256-GCM-SHA384
DHE-DSS-AES256-SHA
DHE-DSS-AES256-SHA256
DHE-DSS-CAMELLIA256-SHA
DHE-RSA-AES256-GCM-SHA384
DHE-RSA-AES256-SHA
DHE-RSA-AES256-SHA256
DHE-RSA-CAMELLIA256-SHA
ECDH-ECDSA-AES256-GCM-SHA384
ECDH-ECDSA-AES256-SHA
ECDH-ECDSA-AES256-SHA384
ECDH-ECDSA-DES-CBC3-SHA
ECDH-RSA-AES256-GCM-SHA384
ECDH-RSA-AES256-SHA
ECDH-RSA-AES256-SHA384
ECDH-RSA-DES-CBC3-SHA
ECDHE-ECDSA-AES128-GCM-SHA256
ECDHE-ECDSA-AES128-SHA
ECDHE-ECDSA-AES128-SHA256
ECDHE-ECDSA-AES256-GCM-SHA384
ECDHE-ECDSA-AES256-SHA
ECDHE-ECDSA-AES256-SHA384
ECDHE-ECDSA-DES-CBC3-SHA
ECDHE-RSA-AES128-GCM-SHA256
ECDHE-RSA-AES128-SHA
ECDHE-RSA-AES128-SHA256
ECDHE-RSA-AES256-GCM-SHA384
ECDHE-RSA-AES256-SHA
ECDHE-RSA-AES256-SHA384
ECDHE-RSA-DES-CBC3-SHA
EDH-DSS-DES-CBC3-SHA
EDH-RSA-DES-CBC3-SHA
PSK-3DES-EDE-CBC-SHA
PSK-AES256-CBC-SHA
SRP-DSS-3DES-EDE-CBC-SHA
SRP-DSS-AES-128-CBC-SHA
SRP-DSS-AES-256-CBC-SHA
SRP-RSA-3DES-EDE-CBC-SHA
SRP-RSA-AES-128-CBC-S
SRP-RSA-AES-256-CBC-SHA

MySQL passes this default cipher list to yaSSL:

AES128-RMD
AES128-SHA
AES256-RMD
AES256-SHA
DES-CBC-SHA
DES-CBC3-RMD
DES-CBC3-SHA
DHE-RSA-AES128-RMD
DHE-RSA-AES128-SHA
DHE-RSA-AES256-RMD
DHE-RSA-AES256-SHA
DHE-RSA-DES-CBC3-RMD
EDH-RSA-DES-CBC-SHA
EDH-RSA-DES-CBC3-SHA
RC4-MD5
RC4-SHA

Monitoring Current Session TLS Protocol and Cipher

To determine which encryption TLS protocol and cipher the current session uses, check the session values of the Ssl_version and Ssl_cipher status variables:

mysql> SHOW SESSION STATUS LIKE 'Ssl_version';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| Ssl_version   | TLSv1 |
+---------------+-------+
mysql> SHOW SESSION STATUS LIKE 'Ssl_cipher';
+---------------+--------------------+
| Variable_name | Value              |
+---------------+--------------------+
| Ssl_cipher    | DHE-RSA-AES256-SHA |
+---------------+--------------------+

If the connection is not encrypted, both variables have an empty value.