https: Apache TLS renegotiation: Debian, Apache2, openssl. How to?

Question

On modern browsers, my site gets marked as sorta insecure:

Google Chrome for example says "The server does not support the TLS renegotiation extension" in the "Page Information".

HTTPS runs fine though, the connection is encrypted and the certificate is valid.

# openssl version
OpenSSL 0.9.8g 19 Oct 2007

# cat /etc/debian_version
5.0.6

# apache2ctl -V
Server version: Apache/2.2.9 (Debian)
Server built:   Apr 20 2010 21:44:40
Server's Module Magic Number: 20051115:15
Server loaded:  APR 1.2.12, APR-Util 1.2.12
Compiled using: APR 1.2.12, APR-Util 1.2.12
Architecture:   64-bit
Server MPM:     ITK
  threaded:     no
    forked:     yes (variable process count)
Server compiled with....
 -D APACHE_MPM_DIR="server/mpm/experimental/itk"
 -D APR_HAS_SENDFILE
 -D APR_HAS_MMAP
 -D APR_HAVE_IPV6 (IPv4-mapped addresses enabled)
 -D APR_USE_SYSVSEM_SERIALIZE
 -D APR_USE_PTHREAD_SERIALIZE
 -D SINGLE_LISTEN_UNSERIALIZED_ACCEPT
 -D APR_HAS_OTHER_CHILD
 -D AP_HAVE_RELIABLE_PIPED_LOGS
 -D DYNAMIC_MODULE_LIMIT=128
 -D HTTPD_ROOT=""
 -D SUEXEC_BIN="/usr/lib/apache2/suexec"
 -D DEFAULT_PIDLOG="/var/run/apache2.pid"
 -D DEFAULT_SCOREBOARD="logs/apache_runtime_status"
 -D DEFAULT_LOCKFILE="/var/run/apache2/accept.lock"
 -D DEFAULT_ERRORLOG="logs/error_log"
 -D AP_TYPES_CONFIG_FILE="/etc/apache2/mime.types"
 -D SERVER_CONFIG_FILE="/etc/apache2/apache2.conf"

I'm using the dotdeb repository for my LAMP setup, hence Apache 2.2.9.

• Is there something wrong with my server configuration?

• Or is there something wrong with the certificate in use?

• Where should I begin tracking down the issue?

Solution

According to the Debian changelog, you're using the apache2 package version 2.2.9-10+lenny8 (the latest one available for Lenny), built Apr 20 2010. Version 2.2.9-10+lenny6 had introduced a quick fix for the problem (CVE-2009-3555):

Reject any client-initiated SSL/TLS renegotiations. This is a partial fix for the TLS renegotiation prefix injection attack (CVE-2009-3555). Any configuration which requires renegotiation for per-directory/location access control or uses "SSLVerifyClient optional" is still vulnerable.

Therefore, you should disable SSLVerifyClient optional in Directory or Location directives.

The TLS renegotiation extension (RFC 5746), which addresses the problem in SSLVerifyClient optional more generally, was implemented in OpenSSL versions 0.9.8m and 1.0.0a, which you would need if you wanted to use it.

If you're not using SSLVerifyClient optional in location/directory directives, your configuration doesn't seem insecure, it just doesn't support this TLS extension that would have allowed you to keep using client-certificate authentication on a per-directory/location basis.

Apache Httpd 2.2.15 also introduced the SSLInsecureRenegotiation directive if you want to force the insecure behaviour (and use OpenSSL 0.9.8m or above).