Now this isn’t email servers, but in terms of websites, ~9% of surveyed sites 
support it: https://www.trustworthyinternet.org/ssl-pulse/ 

 

Frank

 

From: mailop [mailto:mailop-boun...@mailop.org] On Behalf Of Brandon Long via 
mailop
Sent: Wednesday, March 02, 2016 7:30 PM
To: Franck Martin <fmar...@linkedin.com>
Cc: Matthew Huff <mh...@ox.com>; mailop@mailop.org
Subject: Re: [mailop] TLS/SSL DROWN attack with respect to email servers

 

I thought that POODLE required a specific type of fallback that tended to be 
browser specific (ie, prevent a tls connection, forcing the browser to fall 
back to a ssl3 connection), do any smtp servers actually do that?

 

looks like we're down to small enough ssl3 we could disable it, though.  Almost 
all of our ssl3 comes from badoo.com <http://badoo.com> , never heard of it.

 

Who hasn't already disabled ssl2?  I'm kind of shocked at their numbers.

 

Brandon

(not a security expert)

 

On Wed, Mar 2, 2016 at 4:09 PM, Franck Martin via mailop <mailop@mailop.org 
<mailto:mailop@mailop.org> > wrote:

Disable SSLv3 too, because of Poodle.

 

We will need to get rid of RC4, unfortunately this is the only cypher some old 
exchange machines understand. Also falling back to clear text from STARTTLS is 
more and more frowned upon.

 

On Wed, Mar 2, 2016 at 1:45 PM, Matthew Huff <mh...@ox.com 
<mailto:mh...@ox.com> > wrote:

If your mail server still is advertising SSLv2, you SSL private key may be 
vulnerable.

https://www.us-cert.gov/ncas/current-activity/2016/03/01/SSLv2-DROWN-Attack

What's worse, if you are using a wildcard cert, then any other server that is 
using the same cert can be trivially decrypted even if that server is only 
using TLS1.2 and strong cyphers.

I know that there are a number of broken email servers that will bounce mail if 
TLS is negotiated but they can't negotiate older SSL  or weaker cyphers, but 
it's probably a good idea to either: 1) Disable TLS, or 2) Disable SSLv2

----
Matthew Huff             | 1 Manhattanville Rd
Director of Operations   | Purchase, NY 10577
OTA Management LLC       | Phone: 914-460-4039 <tel:914-460-4039> 
aim: matthewbhuff        | Fax:   914-694-5669 <tel:914-694-5669> 



_______________________________________________
mailop mailing list
mailop@mailop.org <mailto:mailop@mailop.org> 
https://chilli.nosignal.org/cgi-bin/mailman/listinfo/mailop

 


_______________________________________________
mailop mailing list
mailop@mailop.org <mailto:mailop@mailop.org> 
https://chilli.nosignal.org/cgi-bin/mailman/listinfo/mailop

 

_______________________________________________
mailop mailing list
mailop@mailop.org
https://chilli.nosignal.org/cgi-bin/mailman/listinfo/mailop

Reply via email to