Configurer le chiffrement TLS d’Apache sous Debian

Avec les récentes failles (POODLE, FREAK..) et les recommandations de l’ANSSI, il est important de n’autoriser, dans la mesure du possible, uniquement que TLSv1.1 et TLSv1.2.

Voici un document très intéressant présentant un état des lieux des récommandations : http://www.ssi.gouv.fr/uploads/IMG/pdf/SSL_TLS_etat_des_lieux_et_recommandations.pdf

Comment configurer (au mieux?) Apache pour Debian Squeeze LTS, Debian Wheezy et Debian Jessie?

L’installation d’Apache est la même pour toutes ces distributions.. elle se fait classiquement par les packages de la distribution :

apt-get install apache2
a2enmod ssl
a2enmod headers
a2ensite default-ssl
service apache2 restart

Les configurations TLS des vhosts (typiquement dans le fichier /etc/apache2/site-available/default-ssl si on reste dans la configuration de base avec un seul vhost) sont basées sur cet outil : https://mozilla.github.io/server-side-tls/ssl-config-generator/

En fait, pour Squeeze LTS (apache 2.2.16), on ne pourra malheureusement proposer ni TLSv1.2 ni TLSv1.1!!! on devra se contenter uniquement TLSv1.. Le mieux est de migrer rapidement vers Jessie pour avoir Apache 2.4 (à moins de compiler à partir des sources ou d’utiliser les backports). Sur une Wheezy (apache 2.2.22), on peut imposer TLSv1.1 et ou TLSv1.2!

Avant de changer la configuration d’un frontal, vérifiez que toutes les applications sont « compatibles ». Si vous avez un serveur CAS.. saura t’il faire du TLSv1.1 ou TLSv1.2?

Squeeze LTS

apache2 (2.2.16-6+squeeze14)
libssl0.9.8 (0.9.8o-4squeeze21)
openssl (0.9.8o-4squeeze21)

Configuration dite « intermediate » :


    ...
    SSLEngine on
    SSLCertificateFile      /path/to/signed_certificate
    SSLCertificateChainFile /path/to/intermediate_certificate
    SSLCertificateKeyFile   /path/to/private/key
    SSLCACertificateFile    /path/to/all_ca_certs

    # intermediate configuration, tweak to your needs
    SSLProtocol             all -SSLv2 -SSLv3
    SSLCipherSuite          ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-AES256-GCM-SHA384:DHE-RSA-AES128-GCM-SHA256:DHE-DSS-AES128-GCM-SHA256:kEDH+AESGCM:ECDHE-RSA-AES128-SHA256:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA:ECDHE-ECDSA-AES128-SHA:ECDHE-RSA-AES256-SHA384:ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES256-SHA:ECDHE-ECDSA-AES256-SHA:DHE-RSA-AES128-SHA256:DHE-RSA-AES128-SHA:DHE-DSS-AES128-SHA256:DHE-RSA-AES256-SHA256:DHE-DSS-AES256-SHA:DHE-RSA-AES256-SHA:AES128-GCM-SHA256:AES256-GCM-SHA384:AES128-SHA256:AES256-SHA256:AES128-SHA:AES256-SHA:AES:CAMELLIA:DES-CBC3-SHA:!aNULL:!eNULL:!EXPORT:!DES:!RC4:!MD5:!PSK:!aECDH:!EDH-DSS-DES-CBC3-SHA:!EDH-RSA-DES-CBC3-SHA:!KRB5-DES-CBC3-SHA
    SSLHonorCipherOrder     on



    # HSTS (mod_headers is required) (15768000 seconds = 6 months)
    Header always set Strict-Transport-Security "max-age=15768000"
    ...

Wheezy

apache2 (2.2.22-13+deb7u4)
libssl1.0.0 (1.0.1e-2+deb7u17) [security]
openssl (1.0.1e-2+deb7u17) [security]

Configuration dite « intermediate » :


    ...
    SSLEngine on
    SSLCertificateFile      /path/to/signed_certificate
    SSLCertificateChainFile /path/to/intermediate_certificate
    SSLCertificateKeyFile   /path/to/private/key
    SSLCACertificateFile    /path/to/all_ca_certs

    # intermediate configuration, tweak to your needs
    SSLProtocol             all -SSLv2 -SSLv3 -TLSv1
    SSLCipherSuite          ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-AES256-GCM-SHA384:DHE-RSA-AES128-GCM-SHA256:DHE-DSS-AES128-GCM-SHA256:kEDH+AESGCM:ECDHE-RSA-AES128-SHA256:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA:ECDHE-ECDSA-AES128-SHA:ECDHE-RSA-AES256-SHA384:ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES256-SHA:ECDHE-ECDSA-AES256-SHA:DHE-RSA-AES128-SHA256:DHE-RSA-AES128-SHA:DHE-DSS-AES128-SHA256:DHE-RSA-AES256-SHA256:DHE-DSS-AES256-SHA:DHE-RSA-AES256-SHA:AES128-GCM-SHA256:AES256-GCM-SHA384:AES128-SHA256:AES256-SHA256:AES128-SHA:AES256-SHA:AES:CAMELLIA:DES-CBC3-SHA:!aNULL:!eNULL:!EXPORT:!DES:!RC4:!MD5:!PSK:!aECDH:!EDH-DSS-DES-CBC3-SHA:!EDH-RSA-DES-CBC3-SHA:!KRB5-DES-CBC3-SHA
    SSLHonorCipherOrder     on



    # HSTS (mod_headers is required) (15768000 seconds = 6 months)
    Header always set Strict-Transport-Security "max-age=15768000"
    ...

Attention ici (contrairement aux possibilités indiquées par l’outils) on a pu rajouter -TLSv1 pour retirer l’utilisation de TLSv1!!

Jessie

apache2 (2.4.10-10)
libssl1.0.0 (1.0.1k-3+deb8u1) [security]
openssl (1.0.1k-3+deb8u1) [security]

Configuration dite « modern » :


    ...
    SSLEngine on
    SSLCertificateFile      /path/to/signed_certificate_followed_by_intermediate_certs
    SSLCertificateKeyFile   /path/to/private/key
    SSLCACertificateFile    /path/to/all_ca_certs

    # modern configuration, tweak to your needs
    SSLProtocol             all -SSLv3 -TLSv1
    SSLCipherSuite          ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-AES256-GCM-SHA384:DHE-RSA-AES128-GCM-SHA256:DHE-DSS-AES128-GCM-SHA256:kEDH+AESGCM:ECDHE-RSA-AES128-SHA256:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA:ECDHE-ECDSA-AES128-SHA:ECDHE-RSA-AES256-SHA384:ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES256-SHA:ECDHE-ECDSA-AES256-SHA:DHE-RSA-AES128-SHA256:DHE-RSA-AES128-SHA:DHE-DSS-AES128-SHA256:DHE-RSA-AES256-SHA256:DHE-DSS-AES256-SHA:DHE-RSA-AES256-SHA:!aNULL:!eNULL:!EXPORT:!DES:!RC4:!3DES:!MD5:!PSK
    SSLHonorCipherOrder     on
    SSLCompression          off

    # OCSP Stapling, only in httpd 2.3.3 and later
    SSLUseStapling          on
    SSLStaplingResponderTimeout 5
    SSLStaplingReturnResponderErrors off

    # HSTS (mod_headers is required) (15768000 seconds = 6 months)
    Header always set Strict-Transport-Security "max-age=15768000"
    ...

SSLStaplingCache        shmcb:/var/run/ocsp(128000)

Configuration dite « intermediate » :


    ...
    SSLEngine on
    SSLCertificateFile      /path/to/signed_certificate_followed_by_intermediate_certs
    SSLCertificateKeyFile   /path/to/private/key
    SSLCACertificateFile    /path/to/all_ca_certs

    # intermediate configuration, tweak to your needs
    SSLProtocol             all -SSLv3
    SSLCipherSuite          ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-AES256-GCM-SHA384:DHE-RSA-AES128-GCM-SHA256:DHE-DSS-AES128-GCM-SHA256:kEDH+AESGCM:ECDHE-RSA-AES128-SHA256:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA:ECDHE-ECDSA-AES128-SHA:ECDHE-RSA-AES256-SHA384:ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES256-SHA:ECDHE-ECDSA-AES256-SHA:DHE-RSA-AES128-SHA256:DHE-RSA-AES128-SHA:DHE-DSS-AES128-SHA256:DHE-RSA-AES256-SHA256:DHE-DSS-AES256-SHA:DHE-RSA-AES256-SHA:AES128-GCM-SHA256:AES256-GCM-SHA384:AES128-SHA256:AES256-SHA256:AES128-SHA:AES256-SHA:AES:CAMELLIA:DES-CBC3-SHA:!aNULL:!eNULL:!EXPORT:!DES:!RC4:!MD5:!PSK:!aECDH:!EDH-DSS-DES-CBC3-SHA:!EDH-RSA-DES-CBC3-SHA:!KRB5-DES-CBC3-SHA
    SSLHonorCipherOrder     on
    SSLCompression          off

    # OCSP Stapling, only in httpd 2.3.3 and later
    SSLUseStapling          on
    SSLStaplingResponderTimeout 5
    SSLStaplingReturnResponderErrors off    

# HSTS (mod_headers is required) (15768000 seconds = 6 months)
    Header always set Strict-Transport-Security "max-age=15768000"
    ...

SSLStaplingCache        shmcb:/var/run/ocsp(128000)

On peut tester les protocoles et algorithmes de chiffrements avec nmap!

Pour une installation d’Apache 2 sur Jessie ça donne ça :

nmap --script ssl-enum-ciphers -p 443 jessie
Nmap scan report for jessie (192.168.0.33)
Host is up (0.00028s latency).
PORT STATE SERVICE
443/tcp open https
| ssl-enum-ciphers:
| SSLv3: No supported ciphers found
| TLSv1.0:
| ciphers:
| TLS_DHE_RSA_WITH_3DES_EDE_CBC_SHA - strong
| TLS_DHE_RSA_WITH_AES_128_CBC_SHA - strong
| TLS_DHE_RSA_WITH_AES_256_CBC_SHA - strong
| TLS_DHE_RSA_WITH_CAMELLIA_128_CBC_SHA - strong
| TLS_DHE_RSA_WITH_CAMELLIA_256_CBC_SHA - strong
| TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA - strong
| TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA - strong
| TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA - strong
| TLS_RSA_WITH_3DES_EDE_CBC_SHA - strong
| TLS_RSA_WITH_AES_128_CBC_SHA - strong
| TLS_RSA_WITH_AES_256_CBC_SHA - strong
| TLS_RSA_WITH_CAMELLIA_128_CBC_SHA - strong
| TLS_RSA_WITH_CAMELLIA_256_CBC_SHA - strong
| compressors:
| NULL
| TLSv1.1:
| ciphers:
| TLS_DHE_RSA_WITH_3DES_EDE_CBC_SHA - strong
| TLS_DHE_RSA_WITH_AES_128_CBC_SHA - strong
| TLS_DHE_RSA_WITH_AES_256_CBC_SHA - strong
| TLS_DHE_RSA_WITH_CAMELLIA_128_CBC_SHA - strong
| TLS_DHE_RSA_WITH_CAMELLIA_256_CBC_SHA - strong
| TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA - strong
| TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA - strong
| TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA - strong
| TLS_RSA_WITH_3DES_EDE_CBC_SHA - strong
| TLS_RSA_WITH_AES_128_CBC_SHA - strong
| TLS_RSA_WITH_AES_256_CBC_SHA - strong
| TLS_RSA_WITH_CAMELLIA_128_CBC_SHA - strong
| TLS_RSA_WITH_CAMELLIA_256_CBC_SHA - strong
| compressors:
| NULL
| TLSv1.2:
| ciphers:
| TLS_DHE_RSA_WITH_3DES_EDE_CBC_SHA - strong
| TLS_DHE_RSA_WITH_AES_128_CBC_SHA - strong
| TLS_DHE_RSA_WITH_AES_128_CBC_SHA256 - strong
| TLS_DHE_RSA_WITH_AES_128_GCM_SHA256 - strong
| TLS_DHE_RSA_WITH_AES_256_CBC_SHA - strong
| TLS_DHE_RSA_WITH_AES_256_CBC_SHA256 - strong
| TLS_DHE_RSA_WITH_AES_256_GCM_SHA384 - strong
| TLS_DHE_RSA_WITH_CAMELLIA_128_CBC_SHA - strong
| TLS_DHE_RSA_WITH_CAMELLIA_256_CBC_SHA - strong
| TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA - strong
| TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA - strong
| TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256 - strong
| TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 - strong
| TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA - strong
| TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384 - strong
| TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 - strong
| TLS_RSA_WITH_3DES_EDE_CBC_SHA - strong
| TLS_RSA_WITH_AES_128_CBC_SHA - strong
| TLS_RSA_WITH_AES_128_CBC_SHA256 - strong
| TLS_RSA_WITH_AES_128_GCM_SHA256 - strong
| TLS_RSA_WITH_AES_256_CBC_SHA - strong
| TLS_RSA_WITH_AES_256_CBC_SHA256 - strong
| TLS_RSA_WITH_AES_256_GCM_SHA384 - strong
| TLS_RSA_WITH_CAMELLIA_128_CBC_SHA - strong
| TLS_RSA_WITH_CAMELLIA_256_CBC_SHA - strong
| compressors:
| NULL
|_ least strength: strong
MAC Address: 08:00:27:9C:95:DE (Cadmus Computer Systems)

Si on utilise la configuration (modern) ci-dessus :

nmap --script ssl-enum-ciphers -p 443 jessie
Starting Nmap 6.40 ( http://nmap.org ) at 2015-07-29 19:10 CEST
Nmap scan report for jessie (192.168.0.33)
Host is up (0.00028s latency).
PORT STATE SERVICE
443/tcp open https
| ssl-enum-ciphers:
| TLSv1.1:
| ciphers:
| TLS_DHE_RSA_WITH_AES_128_CBC_SHA - strong
| TLS_DHE_RSA_WITH_AES_256_CBC_SHA - strong
| TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA - strong
| TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA - strong
| compressors:
| NULL
| TLSv1.2:
| ciphers:
| TLS_DHE_RSA_WITH_AES_128_CBC_SHA - strong
| TLS_DHE_RSA_WITH_AES_128_CBC_SHA256 - strong
| TLS_DHE_RSA_WITH_AES_128_GCM_SHA256 - strong
| TLS_DHE_RSA_WITH_AES_256_CBC_SHA - strong
| TLS_DHE_RSA_WITH_AES_256_CBC_SHA256 - strong
| TLS_DHE_RSA_WITH_AES_256_GCM_SHA384 - strong
| TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA - strong
| TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256 - strong
| TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 - strong
| TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA - strong
| TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384 - strong
| TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 - strong
| compressors:
| NULL
|_ least strength: strong
MAC Address: 08:00:27:9C:95:DE (Cadmus Computer Systems)
Nmap done: 1 IP address (1 host up) scanned in 0.64 seconds

Qu’est-ce qu’une suite cryptographique?

Laisser un commentaire

Votre adresse de messagerie ne sera pas publiée. Les champs obligatoires sont indiqués avec *