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From Jeff Trawick <traw...@gmail.com>
Subject Re: Reading between the lines; changelog
Date Fri, 05 Mar 2010 22:13:44 GMT
On Fri, Mar 5, 2010 at 4:55 PM, William A. Rowe Jr. <wrowe@rowe-clan.net> wrote:
> Anyone looking at the changelog should be terrified of adopting 2.2.15; I'm going
> to modify it thusly (please correct attributions if needed?);
>
>  *) SECURITY: CVE-2009-3555 (cve.mitre.org)
>     mod_ssl: Comprehensive fix of the TLS renegotiation prefix injection
>     attack when compiled against OpenSSL version 0.9.8m or later.

I see what you mean about potential fear; OTOH, maybe "comprehensive
fix" is misleading too.  Joe mentioned adding something to the FAQ
about the issue.  Perhaps that's the only solution.

I feel like we should convey "we've done the best we can as far as we
know; you should definitely use 2.2.15 and 0.9.8m; you'll be fine if
you don't require renegotiation with old/existing clients, but you're
still screwed if you require renegotiation with old/existing clients"
;)

Here's a summary I sent someone recently.

OpenSSL

0.9.8k and before
all legacy renegotiation is allowed
secure renegotiation not implemented

0.9.8l
legacy renegotiation is allowed only if an API call is made; this API
call isn't suitable for use by mod_ssl, so mod_ssl doesn't exploit it
secure renegotiation not implemented

0.9.8m and later
legacy renegotiation is allowed only if an API call is made; this
release has a new API suitable for use by mod_ssl
secure renegotiation is implemented

mod_ssl in general

client-initiated renegotiation is never needed
server-initiated renegotiation is required for some optional mod_ssl
configurations; if the admin needs to disable server-initiated
renegotiation, they have to consider if their configuration is
impacted and how to mitigate

mod_ssl starting in httpd 2.2.15

* client-initiated renegotiation, legacy or new, is always disabled,
regardless of the level of OpenSSL
* one possible MITM attack against server-initiated legacy
renegotiation is protected against, regardless of the level of
OpenSSL; this is not a complete solution though
* when used with OpenSSL 0.9.8m or later:
** mod_ssl sets a request note as well as a request "envvar" to
indicate whether the client supports secure renegotiation
** the new renegotiation protocol is available with no config changes
** legacy renegotiation is disabled by default
** a new directive is provided to enable legacy renegotiation if that
is required because of the client base

Clients

Clients still need to be upgraded to support the new renegotiation protocol.

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