From f0f5a555bee153477d12bcbce90875d46884281c Mon Sep 17 00:00:00 2001 From: Phil Pennock Date: Sun, 6 May 2012 02:50:57 -0700 Subject: Disable SSLv2 by default. --- src/README.UPDATING | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) (limited to 'src/README.UPDATING') diff --git a/src/README.UPDATING b/src/README.UPDATING index 5b6bea869..12335eab8 100644 --- a/src/README.UPDATING +++ b/src/README.UPDATING @@ -39,6 +39,12 @@ Exim version 4.78 the message. No tool has been provided as we believe this is a rare occurence. + * For OpenSSL, SSLv2 is now disabled by default. (GnuTLS does not support + SSLv2). RFC 6176 prohibits SSLv2 and some informal surveys suggest no + actual usage. You can re-enable with the "openssl_options" Exim option, + in the main configuration section. Note that supporting SSLv2 exposes + you to ciphersuite downgrade attacks. + * With OpenSSL 1.0.1+, Exim now supports TLS 1.1 and TLS 1.2. If built against 1.0.1a then you will get a warning message and the "openssl_options" value will not parse "no_tlsv1_1": the value changes @@ -48,8 +54,9 @@ Exim version 4.78 "openssl_options" gains "no_tlsv1_1", "no_tlsv1_2" and "no_compression". COMPATIBILITY WARNING: The default value of "openssl_options" is no longer - "+dont_insert_empty_fragments". We default to unset. That old default was - grandfathered in from before openssl_options became a configuration option. + "+dont_insert_empty_fragments". We default to "+no_sslv2". + That old default was grandfathered in from before openssl_options became a + configuration option. Empty fragments are inserted by default through TLS1.0, to partially defend against certain attacks; TLS1.1+ change the protocol so that this is not needed. The DIEF SSL option was required for some old releases of mail -- cgit v1.2.1