[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date: Mon, 28 Dec 2015 15:55:02 +0000
From: Sevan Janiyan <venture37@...klan.co.uk>
To: oss-security@...ts.openwall.com
Subject: Re: Being vulnerable to POODLE
Hi,
On 28/12/2015 14:32, Florian Weimer wrote:
> How so?
>
> With some OpenSSL versions, it disables the 0/n split to mitigate a
> *different* CBC vulnerability in TLS 1.0, and the client code explicitly
> prevents OpenSSL from using TLS 1.1 and later.
SSLv23_server_method() is called to setup a server without any
restrictions & SSL_CTX_set_options() sets SSL_OP_ALL on the context.
The change I'm proposing explicitly disables the use of SSLv2/v3 so that
we're not reliant on the SSL library (which may be out of date?) to
impose restriction.
Looking up the documentation before I reply, it seems that by using the
SSL_OP_ALL setting, the mitigation you mention is actually disabled. See
SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS & SSL_OP_ALL on[1]
SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS
Disables a countermeasure against a SSL 3.0/TLS 1.0 protocol
vulnerability affecting CBC ciphers, which cannot be handled by some
broken SSL implementations. This option has no effect for connections
using other ciphers.
Sevan
[1] http://openssl.org/docs/manmaster/ssl/SSL_CTX_set_options.html
Powered by blists - more mailing lists
Please check out the
Open Source Software Security Wiki, which is counterpart to this
mailing list.
Confused about mailing lists and their use?
Read about mailing lists on Wikipedia
and check out these
guidelines on proper formatting of your messages.
