mirror of
https://github.com/sonertari/SSLproxy
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502 lines
21 KiB
Groff
502 lines
21 KiB
Groff
.\" SSLsplit - transparent and scalable SSL/TLS interception
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.\" Copyright (c) 2009-2012, Daniel Roethlisberger <daniel@roe.ch>
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.\" All rights reserved.
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.\" http://www.roe.ch/SSLsplit
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice unmodified, this list of conditions, and the following
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.\" disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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.\"
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.TH SSLSPLIT 1 "1 April 2012"
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.SH NAME
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sslsplit \-\- transparent and scalable SSL/TLS interception
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.SH SYNOPSIS
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.na
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.B sslsplit
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[\fB-kCKOPZdDgGseujplLS\fP] \fB-c\fP \fIpem\fP
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\fIproxyspecs\fP [...]
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.br
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.B sslsplit
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[\fB-kCKOPZdDgGseujplLS\fP] \fB-c\fP \fIpem\fP \fB-t\fP \fIdir\fP
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\fIproxyspecs\fP [...]
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.br
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.B sslsplit
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[\fB-OPZdDgGseujplLS\fP] \fB-t\fP \fIdir\fP
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\fIproxyspecs\fP [...]
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.br
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.B sslsplit -E
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.br
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.B sslsplit -V
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.br
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.B sslsplit -h
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.br
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.ad
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.SH DESCRIPTION
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SSLsplit is a tool for man-in-the-middle attacks against SSL/TLS encrypted
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network connections. Connections are transparently intercepted through a
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network address translation engine and redirected to SSLsplit. SSLsplit
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terminates SSL/TLS and initiates a new SSL/TLS connection to the original
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destination address, while logging all data transmitted. SSLsplit is intended
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to be useful for network forensics and penetration testing.
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.LP
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SSLsplit supports plain TCP, plain SSL, HTTP and HTTPS connections over both
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IPv4 and IPv6. For SSL and HTTPS connections, SSLsplit generates and signs
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forged X509v3 certificates on-the-fly, based on the original server certificate
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subject DN and subjectAltName extension. SSLsplit fully supports Server Name
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Indication (SNI) and is able to work with RSA, DSA and ECDSA keys and DHE and
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ECDHE cipher suites. SSLsplit can also use existing certificates of which the
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private key is available, instead of generating forged ones. SSLsplit supports
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NULL-prefix CN certificates and can deny OCSP requests in a generic way.
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.LP
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SSLsplit supports a number of NAT engines, static forwarding and SNI DNS
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lookups to determine the original destination of redirected connections
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(see NAT ENGINES and PROXY SPECIFICATIONS below).
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.LP
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To actually implement an attack, you also need to redirect the traffic to the
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system running \fBsslsplit\fP. Your options include running \fBsslsplit\fP on
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a legitimate router, ARP spoofing, ND spoofing, DNS poisoning, deploying a
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rogue access point (e.g. using hostap mode), physical recabling, malicious VLAN
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reconfiguration or route injection, /etc/hosts modification and so on.
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SSLsplit does not implement the actual traffic redirection.
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.SH OPTIONS
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.TP
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.B \-c \fIpemfile\fP
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Use CA certificate from \fIpemfile\fP to sign certificates forged on-the-fly.
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If \fIpemfile\fP also contains the matching CA private key, it is also loaded,
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otherwise it must be provided with \fB-k\fP.
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If \fIpemfile\fP also contains Diffie-Hellman group parameters, they are also
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loaded, otherwise they can be provided with \fB-g\fP.
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If \fB-t\fP is also given, SSLsplit will only forge a certificate if there is
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no matching certificate in the provided certificate directory.
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.TP
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.B \-C \fIpemfile\fP
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Use CA certificates from \fIpemfile\fP as extra certificates in the certificate
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chain. This is needed if the CA given with \fB-k\fP and \fB-c\fP is a sub-CA,
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in which case any intermediate CA certificates and the root CA certificate must
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be included in the certificate chain.
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.TP
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.B \-d
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Detach from TTY and run as a daemon, logging error messages to syslog instead
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of standard error.
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.TP
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.B \-D
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Run in debug mode, log lots of debugging information to standard error. This
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also forces foreground mode and cannot be used with \fB-d\fP.
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.TP
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.B \-e \fIengine\fP
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Use \fIengine\fP as the default NAT engine for \fIproxyspecs\fP without
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explicit NAT engine, static destination address or SNI mode.
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\fIengine\fP can be any of the NAT engines supported by the system, as
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returned by \fB-E\fP.
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.TP
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.B \-E
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List all supported NAT engines available on the system and exit. See
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NAT ENGINES for a list of NAT engines currently supported by SSLsplit.
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.TP
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.B \-g \fIpemfile\fP
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Use Diffie-Hellman group parameters from \fIpemfile\fP for Ephemereal
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Diffie-Hellman (EDH/DHE) cipher suites. If \fB-g\fP is not given, SSLsplit
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first tries to load DH parameters from the PEM files given by \fB-K\fP,
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\fB-k\fP or \fB-c\fP. If no DH parameters are found in the key files, built-in
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512 or 1024 bit group parameters are automatically used iff a non-RSA private
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key is given with \fB-K\fP.
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This is because DSA/DSS private keys can by themselves only be used for signing
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and thus require DH to exchange an SSL/TLS session key.
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If \fB-g\fP is given, the parameters from the given \fIpemfile\fP will always
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be used, even with RSA private keys (within the cipher suites available in
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OpenSSL).
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The \fB-g\fP option is only available if SSLsplit was built against a version
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of OpenSSL which supports Diffie-Hellman cipher suites.
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.TP
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.B \-G \fIcurve\fP
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Use the named \fIcurve\fP for Ephemereal Elliptic Curve Diffie-Hellman (EECDH)
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cipher suites. If \fB-G\fP is not given, the curve \fBprime256v1\fP is used
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automatically iff a non-RSA private key is given with \fB-K\fP.
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This is because ECDSA/ECDSS private keys can by themselves only be used for
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signing and thus require ECDH to exchange an SSL/TLS session key.
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If \fB-G\fP is given, the named \fIcurve\fP will always be used, even with RSA
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private keys (within the cipher suites available in OpenSSL).
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The \fB-G\fP option is only available if SSLsplit was built against a version
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of OpenSSL which supports Elliptic Curve Diffie-Hellman cipher suites.
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.TP
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.B \-h
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Display help on usage and exit.
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.TP
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.B \-j \fIjaildir\fP
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Change the root directory to \fIjaildir\fP using chroot(2) after opening files.
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If \fB-j\fP is not given, SSLsplit will automatically change root directory to
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\fI/var/empty\fP if run as root and \fB-S\fP is not used.
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.TP
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.B \-k \fIpemfile\fP
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Use CA private key from \fIpemfile\fP to sign certificates forged on-the-fly.
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If \fIpemfile\fP also contains the matching CA certificate, it is also loaded,
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otherwise it must be provided with \fB-c\fP.
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If \fIpemfile\fP also contains Diffie-Hellman group parameters, they are also
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loaded, otherwise they can be provided with \fB-g\fP.
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If \fB-t\fP is also given, SSLsplit will only forge a certificate if there is
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no matching certificate in the provided certificate directory.
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.TP
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.B \-K \fIpemfile\fP
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Use private key from \fIpemfile\fP for certificates forged on-the-fly.
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If \fB-K\fP is not given, SSLsplit will generate a random 1024-bit RSA key.
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.TP
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.B \-l \fIlogfile\fP
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Log connections to \fIlogfile\fP in a single line per connection format,
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including addresses and ports and some HTTP and SSL information, if available.
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.TP
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.B \-L \fIlogfile\fP
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Log connection content to \fIlogfile\fP. The content log will contain a
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parsable log format with transmitted data, prepended with headers identifying
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the connection and the data length of each logged segment.
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.TP
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.B \-O
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Deny all Online Certificate Status Protocol (OCSP) requests on all
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\fIproxyspecs\fP and for all OCSP servers with an OCSP response of
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\fBtryLater\fP, causing OCSP clients to temporarily accept even revoked
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certificates.
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HTTP requests are being treated as OCSP requests if the method is \fBGET\fP
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and the URI contains a syntactically valid OCSPRequest ASN.1 structure
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parsable by OpenSSL, or if the method is \fBPOST\fP and the \fBContent-Type\fP
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is \fBapplication/ocsp-request\fP.
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For this to be effective, SSLsplit must be handling traffic destined to the
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port used by the OCSP server. In particular, SSLsplit must be configured to
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receive traffic to all ports used by OCSP servers of targetted certificates
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within the \fIcertdir\fP specified by \fB-t\fP.
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.TP
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.B \-p \fIpidfile\fP
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Write the process ID to \fIpidfile\fP and refuse to run if the \fIpidfile\fP
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is already in use by another process.
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.TP
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.B \-P
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Passthrough SSL/TLS connections which cannot be split instead of dropping them.
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Connections cannot be split if \fB-c\fP and \fB-k\fP are not given and the
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site does not match any certificate loaded using \fB-t\fP, or if the connection
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to the original server gives SSL/TLS errors. Specifically, this happens if the
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site requests a client certificate. Passthrough with \fB-P\fP results in
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uninterrupted service for the clients, while dropping is the more secure
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alternative if unmonitored connections must be prevented.
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.TP
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.B \-s \fIciphers\fP
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Use OpenSSL \fIciphers\fP specification for both server and client SSL/TLS
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connections. If \fB-s\fP is not given, a cipher list of \fBALL:-aNULL\fP is
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used.
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Normally, SSL/TLS implementations choose the most secure cipher suites, not the
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fastest ones. By specifying an appropriate OpenSSL cipher list, the set of
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cipher suites can be limited to fast algorithms, or \fBeNULL\fP cipher suites
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can be added. Note that for connections to be successful, the SSLsplit cipher
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suites must include at least one cipher suite supported by both the client and
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the server of each connection.
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See ciphers(1) for details on how to construct OpenSSL cipher lists.
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.TP
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.B \-S \fIlogdir\fP
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Log connection content to separate log files under \fIlogdir\fP. For each
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connection, a log file will be written, which will contain both directions of
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data as transmitted. Information about the connection will be contained in
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the filename only.
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If \fB-S\fP is used with \fB-j\fP, \fIlogdir\fP is relative to \fIjaildir\fP.
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If \fB-S\fP is used with \fB-u\fP, \fIlogdir\fP must be writable by \fIuser\fP.
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.TP
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.B \-t \fIcertdir\fP
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Use private key, certificate and certificate chain from PEM files in
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\fIcertdir\fP for sites matching the respective common names, instead of
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using certificates forged on-the-fly. A single PEM file must contain a
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single private key, a single certificate and optionally intermediate and
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root CA certificates to use as certificate chain.
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If \fB-c\fP and \fB-k\fP are also given, certificates will be forged
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on-the-fly for sites matching none of the certificates loaded from
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\fIcertdir\fP.
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Otherwise, connections matching no certificate will be dropped, or if
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\fB-P\fP is given, passed through without splitting SSL/TLS.
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.TP
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.B \-u
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Drop privileges after opening sockets and files by setting the real,
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effective and stored user IDs to \fIuser\fP and loading the appropriate
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primary and ancillary groups. If \fB-u\fP is not given, SSLsplit will drop
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privileges to the stored UID if EUID != UID (setuid bit scenario), or to
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\fBnobody\fP if running with full \fBroot\fP privileges (EUID == UID == 0)
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and \fB-S\fP is not used.
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.TP
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.B \-V
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Display version and compiled features information and exit.
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.TP
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.B \-Z
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Disable SSL/TLS compression on all connections. This is useful if your
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limiting factor is CPU, not network bandwidth.
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The \fB-Z\fP option is only available if SSLsplit was built against a version
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of OpenSSL which supports disabling compression.
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.SH "PROXY SPECIFICATIONS"
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Proxy specifications (\fIproxyspecs\fP) consist of the connection type, listen
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address and static forward address or address resolution mechanism (NAT engine,
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SNI DNS lookup):
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.LP
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.na
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\fBhttps\fP \fIlistenaddr port\fP
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[\fInat-engine\fP|\fIfwdaddr port\fP|\fBsni\fP \fIport\fP]
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.br
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\fBssl\fP \fIlistenaddr port\fP
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[\fInat-engine\fP|\fIfwdaddr port\fP|\fBsni\fP \fIport\fP]
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.br
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\fBhttp\fP \fIlistenaddr port\fP
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[\fInat-engine\fP|\fIfwdaddr port\fP]
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.br
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\fBtcp\fP \fIlistenaddr port\fP
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[\fInat-engine\fP|\fIfwdaddr port\fP]
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.ad
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.TP
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.I listenaddr port
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IPv4 or IPv6 address and port or service name to listen on. This is the
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address and port where the NAT engine should redirect connections to.
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.TP
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.I nat-engine
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NAT engine to query for determining the original destination address and port
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of transparently redirected connections.
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If no engine is given, the default engine is used, unless overridden with
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\fB-e\fP. When using a NAT engine, \fBsslsplit\fP needs to run on the same
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system as the NAT rules redirecting the traffic to \fBsslsplit\fP.
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See NAT ENGINES for a list of supported NAT engines.
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.TP
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.I fwdaddr port
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Static destination address, IPv4 or IPv6, with port or service name. When this
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is used, connections are forwarded to the given server address and port.
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.TP
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\fBsni\fP \fIport\fP
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Use the Server Name Indication (SNI) hostname sent by the client in the
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ClientHello SSL/TLS message to determine the IP address of the server to
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connect to. This only works for \fBssl\fP and \fBhttps\fP \fIproxyspecs\fP and
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needs a port or service name as an argument.
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This is the only way to redirect traffic transparently using NAT rules and run
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\fBsslsplit\fP on a different system than the NAT engine.
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.LP
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.SH "NAT ENGINES"
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SSLsplit currently supports the following NAT engines:
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.TP
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.B pf
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OpenBSD packet filter (pf), also available on FreeBSD and NetBSD.
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Fully supported, including IPv6.
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Assuming inbound interface \fBem0\fP:
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.LP
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.RS
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.nf
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\fBrdr pass on em0 proto tcp from 2001:db8::/64 to any port 80 \\
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-> ::1 port 10080\fP
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\fBrdr pass on em0 proto tcp from 2001:db8::/64 to any port 443 \\
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-> ::1 port 10443\fP
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\fBrdr pass on em0 proto tcp from 192.0.2.0/24 to any port 80 \\
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-> 127.0.0.1 port 10080\fP
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\fBrdr pass on em0 proto tcp from 192.0.2.0/24 to any port 443 \\
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-> 127.0.0.1 port 10443\fP
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.fi
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.RE
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.TP
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.B ipfw
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FreeBSD IP firewall (IPFW), also available on Mac OS X.
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Fully supported on FreeBSD, including IPv6.
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Only supports IPv4 on Mac OS X due to the ancient version of IPFW included.
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.LP
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.RS
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.nf
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\fBipfw add fwd ::1,10080 tcp from 2001:db8::/64 to any 80\fP
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\fBipfw add fwd ::1,10443 tcp from 2001:db8::/64 to any 443\fP
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\fBipfw add fwd 127.0.0.1,10080 tcp from 192.0.2.0/24 to any 80\fP
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\fBipfw add fwd 127.0.0.1,10443 tcp from 192.0.2.0/24 to any 443\fP
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.fi
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.RE
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.TP
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.B ipfilter
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IPFilter (ipfilter, ipf), available on many systems, including FreeBSD, NetBSD,
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Linux and Solaris.
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Only supports IPv4 due to limitations in the SIOCGNATL ioctl(2) interface.
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Assuming inbound interface \fBbge0\fP:
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.LP
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.RS
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.nf
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\fBrdr bge0 0.0.0.0/0 port 80 -> 127.0.0.1 port 10080\fP
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\fBrdr bge0 0.0.0.0/0 port 443 -> 127.0.0.1 port 10443\fP
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.fi
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.RE
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.TP
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.B netfilter
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Linux netfilter using the iptables REDIRECT target.
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Only supports IPv4 due to limitations in the SO_ORIGINAL_DST getsockopt(2)
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interface.
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.LP
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.RS
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.nf
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\fBiptables -t nat -A PREROUTING -s 192.0.2.0/24 \\
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-p tcp --dport 80 \\
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-j REDIRECT --to-ports 10080\fP
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\fBiptables -t nat -A PREROUTING -s 192.0.2.0/24 \\
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-p tcp --dport 443 \\
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-j REDIRECT --to-ports 10443\fP
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.fi
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.RE
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.TP
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.B tproxy
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Linux netfilter using the iptables TPROXY target together with routing
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table magic to allow non-local traffic to originate on local sockets.
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Fully supported, including IPv6.
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.LP
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.RS
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.nf
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\fBip -f inet6 rule add fwmark 1 lookup 100\fP
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\fBip -f inet6 route add local default dev lo table 100\fP
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\fBip6tables -t mangle -N DIVERT\fP
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\fBip6tables -t mangle -A DIVERT -j MARK --set-mark 1\fP
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\fBip6tables -t mangle -A DIVERT -j ACCEPT\fP
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\fBip6tables -t mangle -A PREROUTING -p tcp -m socket -j DIVERT\fP
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\fBip6tables -t mangle -A PREROUTING -s 2001:db8::/64 \\
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-p tcp --dport 80 \\
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-j TPROXY --tproxy-mark 0x1/0x1 --on-port 10080\fP
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\fBip6tables -t mangle -A PREROUTING -s 2001:db8::/64 \\
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-p tcp --dport 443 \\
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-j TPROXY --tproxy-mark 0x1/0x1 --on-port 10443\fP
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\fBip -f inet rule add fwmark 1 lookup 100\fP
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\fBip -f inet route add local default dev lo table 100\fP
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\fBiptables -t mangle -N DIVERT\fP
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\fBiptables -t mangle -A DIVERT -j MARK --set-mark 1\fP
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\fBiptables -t mangle -A DIVERT -j ACCEPT\fP
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\fBiptables -t mangle -A PREROUTING -p tcp -m socket -j DIVERT\fP
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\fBiptables -t mangle -A PREROUTING -s 192.0.2.0/24 \\
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-p tcp --dport 80 \\
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-j TPROXY --tproxy-mark 0x1/0x1 --on-port 10080\fP
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\fBiptables -t mangle -A PREROUTING -s 192.0.2.0/24 \\
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-p tcp --dport 443 \\
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-j TPROXY --tproxy-mark 0x1/0x1 --on-port 10443\fP
|
|
.fi
|
|
.LP
|
|
Note that return path filtering (rp_filter) also needs to be disabled on
|
|
interfaces which handle TPROXY redirected traffic.
|
|
.RE
|
|
.SH EXAMPLES
|
|
Matching the above NAT engine configuration samples, intercept HTTP and HTTPS
|
|
over IPv4 and IPv6 using forged certificates with CA private key \fBca.key\fP
|
|
and certificate \fBca.crt\fP, logging connections to \fBconnect.log\fP and
|
|
connection data into separate files under \fB/tmp\fP (add \fB-e\fP
|
|
\fInat-engine\fP to select the appropriate engine if multiple engines are
|
|
available on your system):
|
|
.LP
|
|
.HS
|
|
.nf
|
|
\fBsslsplit -k ca.key -c ca.crt -l connect.log -L /tmp \\
|
|
https ::1 10443 https 127.0.0.1 10443 \\
|
|
http ::1 10080 http 127.0.0.1 10080\fP
|
|
.fi
|
|
.RE
|
|
.LP
|
|
Intercepting IMAP/IMAPS using the same settings:
|
|
.LP
|
|
.HS
|
|
.nf
|
|
\fBsslsplit -k ca.key -c ca.crt -l connect.log -L /tmp \\
|
|
ssl ::1 10993 ssl 127.0.0.1 10993 \\
|
|
tcp ::1 10143 tcp 127.0.0.1 10143\fP
|
|
.fi
|
|
.RE
|
|
.LP
|
|
A more targetted setup, HTTPS only, using certificate/chain/key files from
|
|
\fB/path/to/cert.d\fP and statically redirecting to \fBwww.example.org\fP
|
|
instead of querying a NAT engine:
|
|
.LP
|
|
.HS
|
|
.nf
|
|
\fBsslsplit -t /path/to/cert.d -l connect.log -L /tmp \\
|
|
https ::1 10443 www.example.org 443 \\
|
|
https 127.0.0.1 10443 www.example.org 443\fP
|
|
.fi
|
|
.RE
|
|
.LP
|
|
The original example, but using SSL options optimized for speed by disabling
|
|
compression and selecting only fast block cipher cipher suites and using a
|
|
precomputed private key \fBleaf.key\fP for the forged certificates
|
|
(most significant speed increase is gained by choosing fast algorithms and
|
|
small keysizes for the CA and leaf private keys; check \fBopenssl speed\fP for
|
|
algorithm performance on your system):
|
|
.LP
|
|
.HS
|
|
.nf
|
|
\fBsslsplit -Z -s NULL:RC4:AES128 -K leaf.key \\
|
|
-k ca.key -c ca.crt -l connect.log -L /tmp \\
|
|
https ::1 10443 https 127.0.0.1 10443 \\
|
|
http ::1 10080 http 127.0.0.1 10080\fP
|
|
.fi
|
|
.RE
|
|
.LP
|
|
The original example, but running as a daemon under user \fBsslsplit\fP and
|
|
writing a PID file:
|
|
.LP
|
|
.HS
|
|
.nf
|
|
\fBsslsplit -d -p /var/run/sslsplit.pid -u sslsplit \\
|
|
-k ca.key -c ca.crt -l connect.log -L /tmp \\
|
|
https ::1 10443 https 127.0.0.1 10443 \\
|
|
http ::1 10080 http 127.0.0.1 10080\fP
|
|
.fi
|
|
.RE
|
|
.LP
|
|
To generate a CA private key \fBca.key\fP and certificate \fBca.crt\fP using
|
|
OpenSSL:
|
|
.LP
|
|
.HS
|
|
.nf
|
|
\fBcat >x509v3ca.cnf <<'EOF'\fP
|
|
[ req ]
|
|
distinguished_name = reqdn
|
|
|
|
[ reqdn ]
|
|
|
|
[ v3_ca ]
|
|
basicConstraints = CA:TRUE
|
|
subjectKeyIdentifier = hash
|
|
authorityKeyIdentifier = keyid:always,issuer:always
|
|
\fBEOF\fP
|
|
|
|
\fBopenssl genrsa -out ca.key 1024\fP
|
|
\fBopenssl req -new -nodes -x509 -sha1 -out ca.crt -key ca.key \\
|
|
-config x509v3ca.cnf -extensions v3_ca \\
|
|
-subj '/O=SSLsplit Root CA/CN=SSLsplit Root CA/' \\
|
|
-set_serial 0 -days 3650\fP
|
|
.fi
|
|
.SH SCALABILITY
|
|
SSLsplit is scalable to a relatively high number of listeners and connections
|
|
due to a multithreaded, event based architecture based on libevent, taking
|
|
advantage of platform specific select() replacements such as kqueue. The main
|
|
thread handles the listeners and signalling, while a number of worker threads
|
|
equal to twice the number of CPU cores is used for handling the actual
|
|
connections in separate event bases, including the CPU-intensive SSL/TLS
|
|
handling.
|
|
.LP
|
|
Care has been taken to choose scalable data structures for caching certificates
|
|
and SSL sessions. Logging is implemented in separate disk writer threads to
|
|
ensure that socket event handling threads don't have to block on disk I/O.
|
|
SSLsplit uses SSL session caching on both ends to minimize the amount of full
|
|
SSL handshakes, but even then, the limiting factor in handling SSL connections
|
|
are the actual bignum computations.
|
|
.SH "SEE ALSO"
|
|
openssl(1), ciphers(1), speed(1),
|
|
pf(4), ipfw(8), iptables(8), ip6tables(8), ip(8),
|
|
hostapd(8), arpspoof(8), parasite6(8), yersinia(8)
|
|
.SH AUTHORS
|
|
Daniel Roethlisberger <daniel@roe.ch>
|
|
.SH BUGS
|
|
Session resumption does not work for SSLv2-only clients. As a workaround,
|
|
clients attepmting to resume a session will always be given a new one and thus
|
|
require a full handshake on every connection, resulting in degraded performance
|
|
with SSLv2 clients. However, SSLv2-only clients should be rare these days.
|