28.8. Setting the supported ciphers on an Apache HTTP Server
By default, the Apache HTTP Server uses the system-wide crypto policy that defines safe default values, which are also compatible with recent browsers. For the list of ciphers the system-wide crypto allows, see the /etc/crypto-policies/back-ends/openssl.config file.
You can manually configure which ciphers your Apache HTTP Server supports. Follow the procedure if your environment requires specific ciphers.
Prerequisites
- TLS encryption is enabled on the server.
Procedure
Edit the
/etc/httpd/conf/httpd.conffile, and add theSSLCipherSuiteparameter to the<VirtualHost>directive for which you want to set the TLS ciphers:SSLCipherSuite "EECDH+AESGCM:EDH+AESGCM:AES256+EECDH:AES256+EDH:!SHA1:!SHA256"This example enables only the
EECDH+AESGCM,EDH+AESGCM,AES256+EECDH, andAES256+EDHciphers and disables all ciphers which use theSHA1andSHA256message authentication code (MAC).Restart the
httpdservice:# systemctl restart httpd
Verification
To display the list of ciphers the Apache HTTP Server supports:
Install the
nmappackage:# dnf install nmapUse the
nmaputility to display the supported ciphers:# nmap --script ssl-enum-ciphers -p 443 example.com ... PORT STATE SERVICE 443/tcp open https | ssl-enum-ciphers: | TLSv1.2: | ciphers: | TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (ecdh_x25519) - A | TLS_DHE_RSA_WITH_AES_256_GCM_SHA384 (dh 2048) - A | TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256 (ecdh_x25519) - A ...