On Tue, Nov 20, 2012, Rainer Canavan wrote: > > On Nov 20, 2012, at 12:47 , "Dr. Stephen Henson" <st...@openssl.org> wrote: > > > On Tue, Nov 20, 2012, Dr. Stephen Henson wrote: > > > >> On Fri, Nov 16, 2012, Rainer Canavan wrote: > >> > >>> > >>> Since openssl is part of a product that we ship, would you consider moving > >>> RC4-MD5 to the front of the cipher list by default a good idea, or are > >>> there > >>> drawbacks that I overlooked, or would this even be preferred, since RC4 > >>> has > >>> been propagated as a mitigating method for the so called BEAST attack? > >>> > >> > >> Whether BEAST is a problem or not depends on your product. I believe > >> (someone > >> correct me if I'm wrong) that for BEAST to work an attacker needs to be > >> able > >> to adaptively inject plaintext which then gets encrypted using the session > >> parameters. If there is no mechanism to do that in your product you aren't > >> vulnerable to BEAST at all so using AES in CBC mode is fine. > > It is possible that our customers use our product in a way that permits > plaintext injection (e.g. javascript into am HTTP response transmitted over > open WiFi networks). > > > Just to clarify that: your description implies your product is an SSL/TLS > > client which can connect to various servers. > > > > Do you need to set SSL_OP_ALL in your product? > > We're using lib curl for the client bit of our products, and that already > sets SSL_OP_ALL (minus SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG, > SSL_OP_NO_TICKET and SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS). >
So you're saying it does *NOT* set SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS? That should be OK then as inserting empty fragments is one way of preventing the BEAST attack but some servers can't handle it. Steve. -- Dr Stephen N. Henson. OpenSSL project core developer. Commercial tech support now available see: http://www.openssl.org ______________________________________________________________________ OpenSSL Project http://www.openssl.org Development Mailing List openssl-dev@openssl.org Automated List Manager majord...@openssl.org
