Opened 4 years ago

Closed 4 years ago

#1137 closed defect (duplicate)

Default cipherlist contains HTTP/2 blacklisted ciphers (in first position)

Reported by: Valerian Saliou Owned by:
Priority: minor Milestone:
Component: nginx-core Version: 1.11.x
Keywords: security, tls Cc:
uname -a: Linux valeriansaliou.name 3.16.0-4-686-pae #1 SMP Debian 3.16.36-1+deb8u2 (2016-10-19) i686 GNU/Linux
nginx -V: nginx version: nginx/1.11.6
built by gcc 4.9.2 (Debian 4.9.2-10)
built with OpenSSL 1.0.1t 3 May 2016
TLS SNI support enabled
configure arguments: --prefix=/etc/nginx --sbin-path=/usr/sbin/nginx --modules-path=/usr/lib/nginx/modules --conf-path=/etc/nginx/nginx.conf --error-log-path=/var/log/nginx/error.log --http-log-path=/var/log/nginx/access.log --pid-path=/var/run/nginx.pid --lock-path=/var/run/nginx.lock --http-client-body-temp-path=/var/cache/nginx/client_temp --http-proxy-temp-path=/var/cache/nginx/proxy_temp --http-fastcgi-temp-path=/var/cache/nginx/fastcgi_temp --http-uwsgi-temp-path=/var/cache/nginx/uwsgi_temp --http-scgi-temp-path=/var/cache/nginx/scgi_temp --user=nginx --group=nginx --with-compat --with-file-aio --with-threads --with-http_addition_module --with-http_auth_request_module --with-http_dav_module --with-http_flv_module --with-http_gunzip_module --with-http_gzip_static_module --with-http_mp4_module --with-http_random_index_module --with-http_realip_module --with-http_secure_link_module --with-http_slice_module --with-http_ssl_module --with-http_stub_status_module --with-http_sub_module --with-http_v2_module --with-mail --with-mail_ssl_module --with-stream --with-stream_realip_module --with-stream_ssl_module --with-stream_ssl_preread_module --with-cc-opt='-g -O2 -fstack-protector-strong -Wformat -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2' --with-ld-opt='-Wl,-z,relro -Wl,-z,now -Wl,--as-needed'

Description

Hello,

Some people reported me not being able to connect to my HTTP/2 services running NGINX v1.11.6 mainline.

I have the option ssl_prefer_server_ciphers to 'on' for PFS, using NGINX default cipherlist. This is what made some strict browsers (compiled by hand, probably w/ some strict encryption perameters - AFAIK) stop being able to connect.

After proceeding a Qualys SSL Test, I got reported that some browsers got an HTTP/2 blacklisted cipher negotiated, with may break all encrypted connections on browsers that enforce a strict implementation of the HTTP/2 RFC.

The list of blacklisted ciphers on HTTP/2: https://http2.github.io/http2-spec/#BadCipherSuites
The passage from the RFC which points this out: http://serverfault.com/posts/712838/revisions

Of course, a fix to this is to set ssl_prefer_server_ciphers to 'off'. But it also break PFS enforcement, while NGINX still proposes blacklisted ciphers, which seems invalid according to specifications. Or, use a custom cipherlist. Though, the default NGINX configuration should come with a proper cipherlist regarding standards, so I suggest removing the blacklisted ciphers (see the first link I attached above).

The TLS1.2 cipherlist as reported by an nmap to my NGINX:

| TLSv1.2:
| ciphers:
| TLS_DHE_RSA_WITH_AES_128_CBC_SHA (dh 4096) - A
| TLS_DHE_RSA_WITH_AES_128_CBC_SHA256 (dh 4096) - A
| TLS_DHE_RSA_WITH_AES_128_GCM_SHA256 (dh 4096) - A
| TLS_DHE_RSA_WITH_AES_256_CBC_SHA (dh 4096) - A
| TLS_DHE_RSA_WITH_AES_256_CBC_SHA256 (dh 4096) - A
| TLS_DHE_RSA_WITH_AES_256_GCM_SHA384 (dh 4096) - A
| TLS_DHE_RSA_WITH_CAMELLIA_128_CBC_SHA (dh 4096) - A
| TLS_DHE_RSA_WITH_CAMELLIA_256_CBC_SHA (dh 4096) - A
| TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA (secp256r1) - A
| TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256 (secp256r1) - A
| TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 (secp256r1) - A
| TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA (secp256r1) - A
| TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384 (secp256r1) - A
| TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (secp256r1) - A
| TLS_RSA_WITH_AES_128_CBC_SHA (rsa 4096) - A
| TLS_RSA_WITH_AES_128_CBC_SHA256 (rsa 4096) - A
| TLS_RSA_WITH_AES_128_GCM_SHA256 (rsa 4096) - A
| TLS_RSA_WITH_AES_256_CBC_SHA (rsa 4096) - A
| TLS_RSA_WITH_AES_256_CBC_SHA256 (rsa 4096) - A
| TLS_RSA_WITH_AES_256_GCM_SHA384 (rsa 4096) - A
| TLS_RSA_WITH_CAMELLIA_128_CBC_SHA (rsa 4096) - A
| TLS_RSA_WITH_CAMELLIA_256_CBC_SHA (rsa 4096) - A

Change History (1)

comment:1 by Maxim Dounin, 4 years ago

Resolution: duplicate
Status: newclosed

Duplicate of #794.

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