[PATCH] httpd: prefer AES-GCM ciphers over AES-CBC

["Peter Müller" <peter.mueller@ipfire.org>]

[-- Attachment #1: Type: text/plain, Size: 3203 bytes --]

CBC ciphers are vulnerable to a bunch of attacks (being
rather academic so far) such as MAC-then-encrypt or
padding oracle.

These seem to be more serious (see
https://blog.qualys.com/technology/2019/04/22/zombie-poodle-and-goldendoodle-vulnerabilities
for further readings) which is why they should be used
for interoperability purposes only.

I plan to remove AES-CBC ciphers for the WebUI at the
end of the year, provided overall security landscape
has not changed until that.

This patch changes the WebUI cipherlist to:
TLS_CHACHA20_POLY1305_SHA256 TLSv1.3 Kx=any      Au=any  Enc=CHACHA20/POLY1305(256) Mac=AEAD
TLS_AES_256_GCM_SHA384  TLSv1.3 Kx=any      Au=any  Enc=AESGCM(256) Mac=AEAD
TLS_AES_128_GCM_SHA256  TLSv1.3 Kx=any      Au=any  Enc=AESGCM(128) Mac=AEAD
ECDHE-ECDSA-CHACHA20-POLY1305 TLSv1.2 Kx=ECDH     Au=ECDSA Enc=CHACHA20/POLY1305(256) Mac=AEAD
ECDHE-ECDSA-AES256-GCM-SHA384 TLSv1.2 Kx=ECDH     Au=ECDSA Enc=AESGCM(256) Mac=AEAD
ECDHE-ECDSA-AES128-GCM-SHA256 TLSv1.2 Kx=ECDH     Au=ECDSA Enc=AESGCM(128) Mac=AEAD
ECDHE-RSA-CHACHA20-POLY1305 TLSv1.2 Kx=ECDH     Au=RSA  Enc=CHACHA20/POLY1305(256) Mac=AEAD
ECDHE-RSA-AES256-GCM-SHA384 TLSv1.2 Kx=ECDH     Au=RSA  Enc=AESGCM(256) Mac=AEAD
ECDHE-RSA-AES128-GCM-SHA256 TLSv1.2 Kx=ECDH     Au=RSA  Enc=AESGCM(128) Mac=AEAD
ECDHE-ECDSA-AES256-SHA384 TLSv1.2 Kx=ECDH     Au=ECDSA Enc=AES(256)  Mac=SHA384
ECDHE-ECDSA-AES128-SHA256 TLSv1.2 Kx=ECDH     Au=ECDSA Enc=AES(128)  Mac=SHA256
ECDHE-RSA-AES256-SHA384 TLSv1.2 Kx=ECDH     Au=RSA  Enc=AES(256)  Mac=SHA384
ECDHE-RSA-AES128-SHA256 TLSv1.2 Kx=ECDH     Au=RSA  Enc=AES(128)  Mac=SHA256

(AES-CBC + ECDSA will be preferred over RSA for performance
reasons. As this cipher order cannot be trivially rebuilt with
OpenSSL cipher stings, it has to be hard-coded.)

All working clients will stay compatible.

Signed-off-by: Peter Müller <peter.mueller(a)ipfire.org>
---
 config/httpd/vhosts.d/ipfire-interface-ssl.conf | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/config/httpd/vhosts.d/ipfire-interface-ssl.conf b/config/httpd/vhosts.d/ipfire-interface-ssl.conf
index f88a6a52a..0166c4920 100644
--- a/config/httpd/vhosts.d/ipfire-interface-ssl.conf
+++ b/config/httpd/vhosts.d/ipfire-interface-ssl.conf
@@ -11,7 +11,7 @@
 
     SSLEngine on
     SSLProtocol all -SSLv3 -TLSv1 -TLSv1.1
-    SSLCipherSuite TLS_CHACHA20_POLY1305_SHA256:TLS_AES_256_GCM_SHA384:TLS_AES_128_GCM_SHA256:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-SHA384:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-CHACHA20-POLY1305:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-RSA-AES256-SHA384:ECDHE-RSA-AES128-SHA256
+    SSLCipherSuite TLS_CHACHA20_POLY1305_SHA256:TLS_AES_256_GCM_SHA384:TLS_AES_128_GCM_SHA256:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-CHACHA20-POLY1305:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-SHA384:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES256-SHA384:ECDHE-RSA-AES128-SHA256
     SSLHonorCipherOrder on
     SSLCompression off
     SSLSessionTickets off
-- 
2.16.4