SSLSPLIT(1)SSLSPLIT(1)NAMEsslsplit-- transparent SSL/TLS interception
SYNOPSISsslsplit [-kCKwWOPZdDgGsrReumjplLSFi] -c pem proxyspecs [...]
sslsplit [-kCKwWOPZdDgGsrReumjplLSFi] -c pem -t dir proxyspecs [...]
sslsplit [-OPZwWdDgGsrReumjplLSFi] -t dir proxyspecs [...]
sslsplit-E
sslsplit-V
sslsplit-h
DESCRIPTION
SSLsplit is a tool for man-in-the-middle attacks against SSL/TLS
encrypted network connections. It is intended to be useful for network
forensics, application security analysis and penetration testing.
SSLsplit is designed to transparently terminate connections that are
redirected to it using a network address translation engine. SSLsplit
then terminates SSL/TLS and initiates a new SSL/TLS connection to the
original destination address, while logging all data transmitted.
Besides NAT based operation, SSLsplit also supports static destinations
and using the server name indicated by SNI as upstream destination.
SSLsplit is purely a transparent proxy and cannot act as a HTTP or
SOCKS proxy configured in a browser. See NAT ENGINES and PROXY SPECI‐
FICATIONS below for specifics on the different modes of operation.
SSLsplit supports plain TCP, plain SSL, HTTP and HTTPS connections over
both IPv4 and IPv6. SSLsplit fully supports Server Name Indication
(SNI) and is able to work with RSA, DSA and ECDSA keys and DHE and
ECDHE cipher suites. Depending on the version of OpenSSL, SSLsplit
supports SSL 3.0, TLS 1.0, TLS 1.1 and TLS 1.2, and optionally SSL 2.0
as well.
For SSL and HTTPS connections, SSLsplit generates and signs forged
X509v3 certificates on-the-fly, mimicking the original server certifi‐
cate's subject DN, subjectAltName extension and other characteristics.
SSLsplit has the ability to use existing certificates of which the pri‐
vate key is available, instead of generating forged ones. SSLsplit
supports NULL-prefix CN certificates but otherwise does not implement
exploits against specific certificate verification vulnerabilities in
SSL/TLS stacks.
SSLsplit implements a number of defences against mechanisms which would
normally prevent MitM attacks or make them more difficult. SSLsplit
can deny OCSP requests in a generic way. For HTTP and HTTPS connec‐
tions, SSLsplit removes response headers for HPKP in order to prevent
public key pinning, for HSTS to allow the user to accept untrusted cer‐
tificates, and Alternate Protocols to prevent switching to QUIC/SPDY.
HTTP compression, encodings and keep-alive are disabled to make the
logs more readable.
As an experimental feature, SSLsplit supports STARTTLS and similar
mechanisms, where a protocol starts on a plain text TCP connection and
is later upgraded to SSL/TLS through protocol-specific means, such as
the STARTTLS command in SMTP. SSLsplit supports generic upgrading of
TCP connections to SSL.
SSLsplit does not automagically redirect any network traffic. To actu‐
ally implement an attack, you also need to redirect the traffic to the
system running sslsplit. Your options include running sslsplit on a
legitimate router, ARP spoofing, ND spoofing, DNS poisoning, deploying
a rogue access point (e.g. using hostap mode), physical recabling,
malicious VLAN reconfiguration or route injection, /etc/hosts modifica‐
tion and so on.
OPTIONS-c pemfile
Use CA certificate from pemfile to sign certificates forged on-
the-fly. If pemfile also contains the matching CA private key,
it is also loaded, otherwise it must be provided with -k. If
pemfile also contains Diffie-Hellman group parameters, they are
also loaded, otherwise they can be provided with -g. If -t is
also given, SSLsplit will only forge a certificate if there is
no matching certificate in the provided certificate directory.
-C pemfile
Use CA certificates from pemfile as extra certificates in the
certificate chain. This is needed if the CA given with -k and
-c is a sub-CA, in which case any intermediate CA certificates
and the root CA certificate must be included in the certificate
chain.
-d Detach from TTY and run as a daemon, logging error messages to
syslog instead of standard error.
-D Run in debug mode, log lots of debugging information to standard
error. This also forces foreground mode and cannot be used with
-d.
-e engine
Use engine as the default NAT engine for proxyspecs without
explicit NAT engine, static destination address or SNI mode.
engine can be any of the NAT engines supported by the system, as
returned by -E.
-E List all supported NAT engines available on the system and exit.
See NAT ENGINES for a list of NAT engines currently supported by
SSLsplit.
-F logspec
Log connection content to separate log files with the given path
specification (see LOG SPECIFICATIONS below). For each connec‐
tion, a log file will be written, which will contain both direc‐
tions of data as transmitted. Information about the connection
will be contained in the filename only.
-g pemfile
Use Diffie-Hellman group parameters from pemfile for Ephemereal
Diffie-Hellman (EDH/DHE) cipher suites. If -g is not given,
SSLsplit first tries to load DH parameters from the PEM files
given by -K, -k or -c. If no DH parameters are found in the key
files, built-in group parameters are automatically used. The -g
option is only available if SSLsplit was built against a version
of OpenSSL which supports Diffie-Hellman cipher suites.
-G curve
Use the named curve for Ephemereal Elliptic Curve Diffie-Hellman
(ECDHE) cipher suites. If -G is not given, a default curve
(prime256v1) is used automatically. The -G option is only
available if SSLsplit was built against a version of OpenSSL
which supports Elliptic Curve Diffie-Hellman cipher suites.
-h Display help on usage and exit.
-i For each connection, find the local process owning the connec‐
tion. This makes process information such as pid, owner:group
and executable path for connections originating on the same sys‐
tem as SSLsplit available to the connect log and enables the
respective -F path specification directives. -i is available on
Mac OS X and FreeBSD; support for other platforms has not been
implemented yet.
-j jaildir
Change the root directory to jaildir using chroot(2) after open‐
ing files. Note that this has implications for sni proxyspecs.
Depending on your operating system, you will need to copy files
such as /etc/resolv.conf to jaildir in order for name resolution
to work. Using sni proxyspecs depends on name resolution. Some
operating systems require special device nodes such as /dev/null
to be present within the jail. Check your system's documenta‐
tion for details.
-k pemfile
Use CA private key from pemfile to sign certificates forged on-
the-fly. If pemfile also contains the matching CA certificate,
it is also loaded, otherwise it must be provided with -c. If
pemfile also contains Diffie-Hellman group parameters, they are
also loaded, otherwise they can be provided with -g. If -t is
also given, SSLsplit will only forge a certificate if there is
no matching certificate in the provided certificate directory.
-K pemfile
Use private key from pemfile for the leaf certificates forged
on-the-fly. If -K is not given, SSLsplit will generate a random
1024-bit RSA key.
-l logfile
Log connections to logfile in a single line per connection for‐
mat, including addresses and ports and some HTTP and SSL infor‐
mation, if available. SIGUSR1 will cause logfile to be re-
opened.
-L logfile
Log connection content to logfile. The content log will contain
a parsable log format with transmitted data, prepended with
headers identifying the connection and the data length of each
logged segment. SIGUSR1 will cause logfile to be re-opened.
-m When dropping privileges using -u, override the target primary
group to be set to group.
-O Deny all Online Certificate Status Protocol (OCSP) requests on
all proxyspecs and for all OCSP servers with an OCSP response of
tryLater, causing OCSP clients to temporarily accept even
revoked certificates. HTTP requests are being treated as OCSP
requests if the method is GET and the URI contains a syntacti‐
cally valid OCSPRequest ASN.1 structure parsable by OpenSSL, or
if the method is POST and the Content-Type is application/ocsp-
request. For this to be effective, SSLsplit must be handling
traffic destined to the port used by the OCSP server. In par‐
ticular, SSLsplit must be configured to receive traffic to all
ports used by OCSP servers of targetted certificates within the
certdir specified by -t.
-p pidfile
Write the process ID to pidfile and refuse to run if the pidfile
is already in use by another process.
-P Passthrough SSL/TLS connections which cannot be split instead of
dropping them. Connections cannot be split if -c and -k are not
given and the site does not match any certificate loaded using
-t, or if the connection to the original server gives SSL/TLS
errors. Specifically, this happens if the site requests a
client certificate. In these situations, passthrough with -P
results in uninterrupted service for the clients, while dropping
is the more secure alternative if unmonitored connections must
be prevented. Passthrough mode currently does not apply to
SSL/TLS errors in the connection from the client, since the con‐
nection from the client cannot easily be retried. Specifically,
-P does not currently work for clients that do not accept forged
certificates.
-r proto
Force SSL/TLS protocol version on both client and server side to
proto by selecting the respective OpenSSL method constructor
instead of the default SSLv23_method() which supports all proto‐
col versions. This is useful when analyzing traffic to a server
that only supports a specific version of SSL/TLS and does not
implement proper protocol negotiation. Depending on build
options and the version of OpenSSL that is used, the following
values for proto are accepted: ssl2, ssl3, tls10, tls11 and
tls12. Note that SSL 2.0 support is not built in by default
because some servers don't handle SSL 2.0 Client Hello messages
gracefully.
-R proto
Disable the SSL/TLS protocol version proto on both client and
server side by disabling the respective protocols in OpenSSL.
To disable multiple protocol versions, -R can be given multiple
times. If -r is also given, there will be no effect in dis‐
abling other protocol versions. Disabling protocol versions is
useful when analyzing traffic to a server that does not handle
some protocol versions well, or to test behaviour with different
protocol versions. Depending on build options and the version
of OpenSSL that is used, the following values for proto are
accepted: ssl2, ssl3, tls10, tls11 and tls12. Note that SSL 2.0
support is not built in by default because some servers don't
handle SSL 2.0 Client Hello messages gracefully.
-s ciphers
Use OpenSSL ciphers specification for both server and client
SSL/TLS connections. If -s is not given, a cipher list of
ALL:-aNULL is used. Normally, SSL/TLS implementations choose
the most secure cipher suites, not the fastest ones. By speci‐
fying an appropriate OpenSSL cipher list, the set of cipher
suites can be limited to fast algorithms, or eNULL cipher suites
can be added. Note that for connections to be successful, the
SSLsplit cipher suites must include at least one cipher suite
supported by both the client and the server of each connection.
See ciphers(1) for details on how to construct OpenSSL cipher
lists.
-S logdir
Log connection content to separate log files under logdir. For
each connection, a log file will be written, which will contain
both directions of data as transmitted. Information about the
connection will be contained in the filename only.
-t certdir
Use private key, certificate and certificate chain from PEM
files in certdir for connections to hostnames matching the
respective certificates, instead of using certificates forged
on-the-fly. A single PEM file must contain a single private
key, a single certificate and optionally intermediate and root
CA certificates to use as certificate chain. When using -t,
SSLsplit will first attempt to use a matching certificate loaded
from certdir. If -c and -k are also given, certificates will be
forged on-the-fly for sites matching none of the common names in
the certificates loaded from certdir. Otherwise, connections
matching no certificate will be dropped, or if -P is given,
passed through without splitting SSL/TLS.
-u Drop privileges after opening sockets and files by setting the
real, effective and stored user IDs to user and loading the
appropriate primary and ancillary groups. If -u is not given,
SSLsplit will drop privileges to the stored UID if EUID != UID
(setuid bit scenario), or to nobody if running with full root
privileges (EUID == UID == 0). Due to an Apple bug, -u cannot
be used with pf proxyspecs on Mac OS X.
-V Display version and compiled features information and exit.
-w gendir
Write generated keys and certificates to individual files in
gendir. For keys, the key identifier is used as filename, which
consists of the SHA-1 hash of the ASN.1 bit string of the public
key, as referenced by the subjectKeyIdentifier extension in cer‐
tificates. For certificates, the SHA-1 fingerprints of the
original and the used (forged) certificate are combined to form
the filename. Note that only newly generated certificates are
written to disk.
-W gendir
Same as -w, but also write original certificates and certifi‐
cates not newly generated, such as those loaded from -t.
-Z Disable SSL/TLS compression on all connections. This is useful
if your limiting factor is CPU, not network bandwidth. The -Z
option is only available if SSLsplit was built against a version
of OpenSSL which supports disabling compression.
PROXY SPECIFICATIONS
Proxy specifications (proxyspecs) consist of the connection type, lis‐
ten address and static forward address or address resolution mechanism
(NAT engine, SNI DNS lookup):
https listenaddr port [nat-engine|fwdaddr port|sni port]
ssl listenaddr port [nat-engine|fwdaddr port|sni port]
http listenaddr port [nat-engine|fwdaddr port]
tcp listenaddr port [nat-engine|fwdaddr port]
autossl listenaddr port [nat-engine|fwdaddr port]
https SSL/TLS interception with HTTP protocol decoding, including the
removal of HPKP, HSTS and Alternate Protocol response headers.
ssl SSL/TLS interception without any lower level protocol decoding;
decrypted connection content is treated as opaque stream of
bytes and not modified.
http Plain TCP connection without SSL/TLS, with HTTP protocol decod‐
ing, including the removal of HPKP, HSTS and Alternate Protocol
response headers.
tcp Plain TCP connection without SSL/TLS and without any lower level
protocol decoding; decrypted connection content is treated as
opaque stream of bytes and not modified.
autossl
Plain TCP connection until a Client Hello SSL/TLS message
appears in the byte stream, then automatic upgrade to SSL/TLS
interception. This is generic, protocol-independent STARTTLS
support, that may erroneously trigger on byte sequences that
look like Client Hello messages even though there was no actual
STARTTLS command issued. This is an experimental feature and
may in its current state miss some Client Hello messages depend‐
ing on circumstances. YMMV. Testing and patches highly wel‐
come.
listenaddr port
IPv4 or IPv6 address and port or service name to listen on.
This is the address and port where the NAT engine should redi‐
rect connections to.
nat-engine
NAT engine to query for determining the original destination
address and port of transparently redirected connections. If no
engine is given, the default engine is used, unless overridden
with -e. When using a NAT engine, sslsplit needs to run on the
same system as the NAT rules redirecting the traffic to
sslsplit. See NAT ENGINES for a list of supported NAT engines.
fwdaddr port
Static destination address, IPv4 or IPv6, with port or service
name. When this is used, connections are forwarded to the given
server address and port. If fwdaddr is a hostname, it will be
resolved to an IP address.
sni port
Use the Server Name Indication (SNI) hostname sent by the client
in the Client Hello SSL/TLS message to determine the IP address
of the server to connect to. This only works for ssl and https
proxyspecs and needs a port or service name as an argument.
Because this requires DNS lookups, it is preferrable to use NAT
engine lookups (see above), except when that is not possible,
such as when there is no supported NAT engine or when running
sslsplit on a different system than the NAT rules redirecting
the actual connections. Note that when using -j with sni, you
may need to prepare jaildir to make name resolution work from
within the chroot directory.
SIGNALS
A running sslsplit accepts SIGINT and SIGQUIT for a clean shutdown and
SIGUSR1 to re-open the long-living log files (-l and -L). Per-connec‐
tion log files (-S and -F) are not re-opened because their filename is
specific to the connection.
LOG SPECIFICATIONS
Log specifications are composed of zero or more printf-style direc‐
tives; ordinary characters are included directly in the output path.
SSLsplit current supports the following directives:
%T The initial connection time as an ISO 8601 UTC timestamp.
%d The destination host and port, separated by a comma, IPv6
addresses using underscore instead of colon.
%D The destination host, IPv6 addresses using underscore instead of
colon.
%p The destination port.
%s The source host and port, separated by a comma, IPv6 addresses
using underscore instead of colon.
%S The source host, IPv6 addresses using underscore instead of
colon.
%q The source port.
%x The name of the local process. Requires -i to be used. If
process information is unavailable, this directive will be omit‐
ted from the output path.
%X The full path of the local process. Requires -i to be used. If
process information is unavailable, this directive will be omit‐
ted from the output path.
%u The username or numeric uid of the local process. Requires -i
to be used. If process information is unavailable, this direc‐
tive will be omitted from the output path.
%g The group name or numeric gid of the local process. Requires -i
to be used. If process information is unavailable, this direc‐
tive will be omitted from the output path.
%% A literal '%' character.
NAT ENGINES
SSLsplit currently supports the following NAT engines:
pf OpenBSD packet filter (pf) rdr/rdr-to NAT redirects, also avail‐
able on FreeBSD, NetBSD and Mac OS X. Fully supported, includ‐
ing IPv6. Note that SSLsplit needs permission to open /dev/pf
for reading, which by default means that it needs to run under
root privileges. Assuming inbound interface em0, first in old
(FreeBSD, Mac OS X), then in new (OpenBSD 4.7+) syntax:
rdr pass on em0 proto tcp from 2001:db8::/64 to any port 80 \
-> ::1 port 10080
rdr pass on em0 proto tcp from 2001:db8::/64 to any port 443 \
-> ::1 port 10443
rdr pass on em0 proto tcp from 192.0.2.0/24 to any port 80 \
-> 127.0.0.1 port 10080
rdr pass on em0 proto tcp from 192.0.2.0/24 to any port 443 \
-> 127.0.0.1 port 10443
pass in quick on em0 proto tcp from 2001:db8::/64 to any \
port 80 rdr-to ::1 port 10080
pass in quick on em0 proto tcp from 2001:db8::/64 to any \
port 443 rdr-to ::1 port 10443
pass in quick on em0 proto tcp from 192.0.2.0/24 to any \
port 80 rdr-to 127.0.0.1 port 10080
pass in quick on em0 proto tcp from 192.0.2.0/24 to any \
port 443 rdr-to 127.0.0.1 port 10443
ipfw FreeBSD IP firewall (IPFW) divert sockets, also available on Mac
OS X. Available on FreeBSD and OpenBSD using pf divert-to.
Fully supported on FreeBSD and OpenBSD, including IPv6. Only
supports IPv4 on Mac OS X due to the ancient version of IPFW
included. First in IPFW, then in pf divert-to syntax:
ipfw add fwd ::1,10080 tcp from 2001:db8::/64 to any 80
ipfw add fwd ::1,10443 tcp from 2001:db8::/64 to any 443
ipfw add fwd 127.0.0.1,10080 tcp from 192.0.2.0/24 to any 80
ipfw add fwd 127.0.0.1,10443 tcp from 192.0.2.0/24 to any 443
pass in quick on em0 proto tcp from 2001:db8::/64 to any \
port 80 divert-to ::1 port 10080
pass in quick on em0 proto tcp from 2001:db8::/64 to any \
port 443 divert-to ::1 port 10443
pass in quick on em0 proto tcp from 192.0.2.0/24 to any \
port 80 divert-to 127.0.0.1 port 10080
pass in quick on em0 proto tcp from 192.0.2.0/24 to any \
port 443 divert-to 127.0.0.1 port 10443
ipfilter
IPFilter (ipfilter, ipf), available on many systems, including
FreeBSD, NetBSD, Linux and Solaris. Note that SSLsplit needs
permission to open /dev/ipnat for reading, which by default
means that it needs to run under root privileges. Only supports
IPv4 due to limitations in the SIOCGNATL ioctl(2) interface.
Assuming inbound interface bge0:
rdr bge0 0.0.0.0/0 port 80 -> 127.0.0.1 port 10080
rdr bge0 0.0.0.0/0 port 443 -> 127.0.0.1 port 10443
netfilter
Linux netfilter using the iptables REDIRECT target. Only sup‐
ports IPv4 due to limitations in the SO_ORIGINAL_DST getsock‐
opt(2) interface.
iptables -t nat -A PREROUTING -s 192.0.2.0/24 \
-p tcp --dport 80 \
-j REDIRECT --to-ports 10080
iptables -t nat -A PREROUTING -s 192.0.2.0/24 \
-p tcp --dport 443 \
-j REDIRECT --to-ports 10443
Note that SSLsplit is only able to accept incoming connections
if it binds to the correct IP address (e.g. 192.0.2.1) or on all
interfaces (0.0.0.0). REDIRECT uses the local interface address
of the incoming interface as target IP address, or 127.0.0.1 for
locally generated packets.
tproxy Linux netfilter using the iptables TPROXY target together with
routing table magic to allow non-local traffic to originate on
local sockets. Fully supported, including IPv6.
ip -f inet6 rule add fwmark 1 lookup 100
ip -f inet6 route add local default dev lo table 100
ip6tables -t mangle -N DIVERT
ip6tables -t mangle -A DIVERT -j MARK --set-mark 1
ip6tables -t mangle -A DIVERT -j ACCEPT
ip6tables -t mangle -A PREROUTING -p tcp -m socket -j DIVERT
ip6tables -t mangle -A PREROUTING -s 2001:db8::/64 \
-p tcp --dport 80 \
-j TPROXY --tproxy-mark 0x1/0x1 --on-port 10080
ip6tables -t mangle -A PREROUTING -s 2001:db8::/64 \
-p tcp --dport 443 \
-j TPROXY --tproxy-mark 0x1/0x1 --on-port 10443
ip -f inet rule add fwmark 1 lookup 100
ip -f inet route add local default dev lo table 100
iptables -t mangle -N DIVERT
iptables -t mangle -A DIVERT -j MARK --set-mark 1
iptables -t mangle -A DIVERT -j ACCEPT
iptables -t mangle -A PREROUTING -p tcp -m socket -j DIVERT
iptables -t mangle -A PREROUTING -s 192.0.2.0/24 \
-p tcp --dport 80 \
-j TPROXY --tproxy-mark 0x1/0x1 --on-port 10080
iptables -t mangle -A PREROUTING -s 192.0.2.0/24 \
-p tcp --dport 443 \
-j TPROXY --tproxy-mark 0x1/0x1 --on-port 10443
Note that return path filtering (rp_filter) also needs to be
disabled on interfaces which handle TPROXY redirected traffic.
EXAMPLES
Matching the above NAT engine configuration samples, intercept HTTP and
HTTPS over IPv4 and IPv6 using forged certificates with CA private key
ca.key and certificate ca.crt, logging connections to connect.log and
connection data into separate files under /tmp (add -e nat-engine to
select the appropriate engine if multiple engines are available on your
system):
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
If the Linux netfilter engine is used with the iptables REDIRECT tar‐
get, it is important to listen to the correct IP address (e.g.
192.0.2.1) or on all interfaces (0.0.0.0), otherwise SSLsplit is not
able to accept incoming connections.
Intercepting IMAP/IMAPS using the same settings:
sslsplit-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
A more targetted setup, HTTPS only, using certificate/chain/key files
from /path/to/cert.d and statically redirecting to www.example.org
instead of querying a NAT engine:
sslsplit-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
The original example, but using SSL options optimized for speed by dis‐
abling compression and selecting only fast cipher cipher suites and
using a precomputed private key leaf.key 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 openssl
speed for algorithm performance on your system. Note that clients may
not support all algorithms and key sizes. Also, some clients warn
their users about cipher suites they consider weak.
sslsplit-Z -s NULL:RC4:AES128:-DHE -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
The original example, but running as a daemon under user sslsplit and
writing a PID file:
sslsplit-d -p /var/run/sslsplit.pid -usslsplit \
-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
To generate a CA private key ca.key and certificate ca.crt using
OpenSSL:
cat >x509v3ca.cnf <<'EOF'
[ req ]
distinguished_name = reqdn
[ reqdn ]
[ v3_ca ]
basicConstraints = CA:TRUE
subjectKeyIdentifier = hash
authorityKeyIdentifier = keyid:always,issuer:always
EOF
openssl genrsa -out ca.key 2048
openssl req -new -nodes -x509 -sha256 -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
NOTES
SSLsplit is able to handle 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.
Care has been taken to choose well-performing data structures for
caching certificates and SSL sessions. Logging is implemented in sepa‐
rate disk writer threads to ensure that socket event handling threads
don't have to block on disk I/O. DNS lookups are performed asynchro‐
niously. 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.
SEE ALSOopenssl(1), ciphers(1), speed(1), pf(4), ipfw(8), iptables(8),
ip6tables(8), ip(8), hostapd(8), arpspoof(8), parasite6(8),
yersinia(8), https://www.roe.ch/SSLsplit
AUTHORS
SSLsplit was written by Daniel Roethlisberger <daniel@roe.ch>.
The following individuals have contributed code or documentation, in
chronological order of their first contribution: Steve Wills, Landon
Fuller, Wayne Jensen, Rory McNamara, Alexander Neumann, Adam Jacob
Muller and Richard Poole.
BUGS
Use Github for submission of bug reports or patches:
https://github.com/droe/sslsplit
1 April 2012 SSLSPLIT(1)
