Re-negotiation handshake failed: Not accepted b...

Re-negotiation handshake failed: Not accepted by client!?

Last updated: Fri, 08 Jan 2010 06:04:42 -0800 View thread at OpenSSL Users

The SSL renegotiation insecurity has two aspects, namely client 
initiated renegotiation and server initiated renegotiation. Both of them 
can be used by a man in the middle as an attack vector.

Renegotiations are needed for an Apache https configurations only, if 
you have a complex SSL configuration that has various different SSL 
requirements in the same vhost, like requiring client certs only for 
some Directory, or changing the allowed cipher specs for some Directory 
(or Location).

If you do not use such a configuration, the best and at the moment only 
way to be safe against the attack is upgrading to OpenSSl 0.9.8l.

There is a patch for Apache 2.2.14 which completely disables client 
initiated renegotiation thereby still allowing server side renegotiation:

http://www.apache.org/dist/httpd/patches/apply_to_2.2.14/ 

This makes you safe from (only) one half of the attack without an 
OpenSSL upgrade and still allows the complex configs to work. An 
enhancement of this patch which should prevent all server side 
renegotiation attacks known at the moment has been applied to the 2.2.x 
branch very recently:

http://svn.apache.org/viewvc?rev=896900&view=rev 

The first patch has been backported and suggested for 2.0:

http://svn.apache.org/viewvc?view=revision&revision=882861  http://people.apache.org/~rjung/patches/cve-2009-3555_httpd_[..] 

and for 1.3:

  

A backport for the second patch does not yet exist.

I think further discussion about Apache specific question are a better 
fit for the Apache httpd users list.

Regards,

Rainer