SSLsplit Package Description

SSLsplit is a tool for man-in-the-middle attacks against SSL/TLS encrypted network connections. Connections are transparently intercepted through a network address translation engine and redirected to SSLsplit. SSLsplit terminates SSL/TLS and initiates a new SSL/TLS connection to the original destination address, while logging all data transmitted. SSLsplit is intended to be useful for network forensics and penetration testing.

SSLsplit supports plain TCP, plain SSL, HTTP and HTTPS connections over both IPv4 and IPv6. For SSL and HTTPS connections, SSLsplit generates and signs forged X509v3 certificates on-the-fly, based on the original server certificate subject DN and subjectAltName extension. SSLsplit fully supports Server Name Indication (SNI) and is able to work with RSA, DSA and ECDSA keys and DHE and ECDHE cipher suites. SSLsplit can also use existing certificates of which the private key is available, instead of generating forged ones. SSLsplit supports NULL-prefix CN certificates and can deny OCSP requests in a generic way. SSLsplit removes HPKP response headers in order to prevent public key pinning.

SSLsplit Homepage | Kali SSLsplit Repo

  • Author: Daniel Roethlisberger
  • License: BSD

Tools included in the sslsplit package

sslsplit – Transparent and scalable SSL/TLS interception
root@kali:~# sslsplit -h
Usage: sslsplit [options...] [proxyspecs...]
  -c pemfile  use CA cert (and key) from pemfile to sign forged certs
  -k pemfile  use CA key (and cert) from pemfile to sign forged certs
  -C pemfile  use CA chain from pemfile (intermediate and root CA certs)
  -K pemfile  use key from pemfile for leaf certs (default: generate)
  -q crlurl   use URL as CRL distribution point for all forged certs
  -t certdir  use cert+chain+key PEM files from certdir to target all sites
              matching the common names (non-matching: generate if CA)
  -w gendir   write leaf key and only generated certificates to gendir
  -W gendir   write leaf key and all certificates to gendir
  -O          deny all OCSP requests on all proxyspecs
  -P          passthrough SSL connections if they cannot be split because of
              client cert auth or no matching cert and no CA (default: drop)
  -a pemfile  use cert from pemfile when destination requests client certs
  -b pemfile  use key from pemfile when destination requests client certs
  -g pemfile  use DH group params from pemfile (default: keyfiles or auto)
  -G curve    use ECDH named curve (default: prime256v1)
  -Z          disable SSL/TLS compression on all connections
  -r proto    only support one of tls10 tls11 tls12 (default: all)
  -R proto    disable one of tls10 tls11 tls12 (default: none)
  -s ciphers  use the given OpenSSL cipher suite spec (default: ALL:-aNULL)
  -e engine   specify default NAT engine to use (default: netfilter)
  -E          list available NAT engines and exit
  -u user     drop privileges to user (default if run as root: nobody)
  -m group    when using -u, override group (default: primary group of user)
  -j jaildir  chroot() to jaildir (impacts sni proxyspecs, see manual page)
  -p pidfile  write pid to pidfile (default: no pid file)
  -l logfile  connect log: log one line summary per connection to logfile
  -L logfile  content log: full data to file or named pipe (excludes -S/-F)
  -S logdir   content log: full data to separate files in dir (excludes -L/-F)
  -F pathspec content log: full data to sep files with % subst (excl. -L/-S):
              %T - initial connection time as an ISO 8601 UTC timestamp
              %d - destination host and port
              %D - destination host
              %p - destination port
              %s - source host and port
              %S - source host
              %q - source port
              %% - literal '%'
      e.g.    "/var/log/sslsplit/%T-%s-%d.log"
  -M logfile  log master keys to logfile in SSLKEYLOGFILE format
  -d          daemon mode: run in background, log error messages to syslog
  -D          debug mode: run in foreground, log debug messages on stderr
  -V          print version information and exit
  -h          print usage information and exit
  proxyspec = type listenaddr+port [natengine|targetaddr+port|"sni"+port]
      e.g.    http 8080 80  # http/4; static hostname dst
              https ::1 8443 2001:db8::1 443   # https/6; static address dst
              https 9443 sni 443     # https/4; SNI DNS lookups
              tcp 10025              # tcp/4; default NAT engine
              ssl 2001:db8::2 9999 pf          # ssl/6; NAT engine 'pf'
              autossl ::1 10025                # autossl/6; STARTTLS et al
  sslsplit -k ca.key -c ca.pem -P  https 8443  https ::1 8443

sslsplit Usage Example

Run in debug mode (-D), log the connections (-l connections.log), set the chroot jail (-j /tmp/sslsplit/), save files to disk (-S /tmp/), specify the key (-k ca.key), specify the cert (-c ca.crt), specify ssl (ssl), and configure the proxy ( 8443 tcp 8080):

root@kali:~# sslsplit -D -l connections.log -j /tmp/sslsplit/ -S /tmp/ -k ca.key -c ca.crt ssl 8443 tcp 8080
Generated RSA key for leaf certs.
SSLsplit 0.4.6 (built 2013-06-06)
Copyright (c) 2009-2013, Daniel Roethlisberger <>
NAT engines: netfilter* tproxy
compiled against OpenSSL 1.0.1e 11 Feb 2013 (1000105f)
rtlinked against OpenSSL 1.0.1e 11 Feb 2013 (1000105f)
TLS Server Name Indication (SNI) supported
OpenSSL is thread-safe with THREADID