OWASP SSL advanced forensic tool / OWASP SSL audit for testers

O-Saft is an easy to use tool to show informations about SSL certificate and tests the SSL connection according given list of ciphers and various SSL configurations.

It’s designed to be used by penetration testers, security auditors or server administrators. The idea is to show the important informations or the special checks with a simple call of the tool. However, it provides a wide range of options so that it can be used for comprehensive and special checks by experienced people.

O-Saft is a command-line tool, so it can be used offline and in closed environments. There is also a GUI based on Tcl/Tk. However, it can simply be turned into an online CGI-tool (please read documentation first).


Quick Installation:

  • Download and unpack o-saft.tgz (Stable Release)
  • to run o-saft: Ensure that following perl modules (and their dependencies) are installed
    • IO::Socket::INET, IO::Socket::SSL, Net::SSLeay
    • Net::SSLinfo, Net::SSLhello (which are part of the tarball)
  • read and (re-)move o-saft-README
  • Show help
     o-saft --help=commands
     o-saft --help
  • Start
     o-saft +info  your.tld
     o-saft +check your.tld
     o-saft +quick your.tld
     o-saft +cipherall your.tld
     o-saft +cipherall --starttls=pop3 pop3.your.tld:110
     o-saft +info mail.tld:25 --starttls
  • to run the optional checkAllCiphers (tiny program to check solely ciphers, like command ‘+cipherall’):
    It usually does not need any perl module to be additionally installed
    • Socket (should be part of your perl installation)
    • Net::SSLhello (which is part of the tarball)
    • NET::DNS (only needed, if option ‘–mx’ is used)
  • Start
     checkAllCiphers your.tld
     checkAllCiphers --starttls=pop3 pop3.your.tld:110
     checkAllCiphers --mx your.tld:25 --starttls=smtp
  • Simple GUI
     o-saft.tcl your.tld
  • Kali 2019
     apt install o-saft # installs version 19.01.19
     apt install libidn11-dev libidn2-0-dev libzip-dev libsctp-dev libkrb5-dev
     cd /usr/share/o-saft
     # get updated script
     curl -O contrib/install_openssl.sh https://raw.githubusercontent.com/OWASP/O-Saft/master/contrib/install_openssl.sh
     sh contrib/install_openssl.sh --m
     # enjoy commands as described before ...


The main idea is to have a tool which works on common platforms and can simply be automated.

In a Nutshell:

  • show SSL connection details
  • show certificate details
  • check for supported ciphers
  • check for ciphers provided in your own libssl.so and libcrypt.so
  • check for ciphers without any dependency to a library (+cipherall)
  • checks the server’s priority for ciphers (+cipherall)
  • check for special HTTP(S) support (like SNI, HSTS, certificate pinning, SSTP)
  • check for vulnerabilities (BEAST, CRIME, DROWN, FREAK, Heartbleed, Lucky 13, POODLE, RC4 Bias, Sweet32 …)
  • check the length of Diffie Hellman Parameters by the cipher (+cipherall needs option ‘–experimental’)
  • may check for a single attribute
  • may check multiple targets at once
  • can be scripted (headless or as CGI)
  • should work on any platform (just needs perl, openssl optional)
  • can be used in CI / CD environments
  • output format can be customized
  • various trace and debug options to hunt unusual connection problems
  • supports STARTTLS for various protocols
    • SMTP, POP3, IMAP, LDAP, RDP, XMPP, IRC (experimental) …
    • customize your own STARTTLS sequence using –starttls=’CUSTOM’, see help for ‘–starttls_phase1..5’ and ‘–starttls_error1..3’
    • without using openssl
    • slows down to prevent blockades of requests due to too much connections (supported for some protocols like SMTP)
  • Proxy is supported (besides commands using openssl)
  • check of STARTTLS/SMTP for all servers of a MX Resource Record (e.g. checkAllCiphers –mx your.tld:25 –starttls=smtp)
  • checkAllCiphers.pl and ‘+cipherall’ support DTLS for ‘–experimental’ use (if records are not fragmented)

New Features of Test Version

Quick Installation (latest version 23.04.23):

  • Download and unpack master.zip from github.com/OWASP/O-Saft or use o-saft.tgz
  • Start INSTALL.sh (if you want)
  • Enjoy new functionality:
    • ‘+cipherraw’ and ‘checkAllCiphers.pl’ changed bahavior to check sni (now the default is to use solely sni >=tls1
      • new option –togglesni tests without and with sni in one call
    • checkAllCiphers.pl/+cipherall: shows the length of dh_parameter for ciphers with DHE and DH_anon, shows the elliptic curve that the server prefers for ECDHE (independant from openssl)
    • checkAllCiphers.pl/+cipherall: support of fagmented messages reassembling SSL/TLS-records
    • please give us feedback via github

  • Where can I get missing Perl-Modules?
    This depends on your OS and Perl installation, but just try ‘‘cpan '', e.g. ''cpan Net:DNS''
    • I am connected to the internet via a Proxy
      open the cpan-shell using ‘cpan’ and configure your proxy settings: ‘o conf init /proxy/’
    • I can not download the requested files (the proxy needs authentication)
      run ‘cpan ' several times, read the error messages and copy the requested files manually to the paths (without any additional temporary extension of the name),
      e.g. http://www.cpan.org/authors/01mailrc.txt.gz => /cpan/sources/authors/01mailrc.txt.gz
  • I get the Error “invalid SSL_version specified at …/perl/vendor/lib/IO/Socket/SSL.pm line …”
    • add options “–notlsv13 –nodtlsv1”, e.g. “perl o-saft.pl +info your.tld –notlsv13 –nodtlsv1”
    • use ‘‘+cipherall’’ to check the ciphers for all protocols
  • My local SSL libraries do not support legacy Protocols like SSLv2, SSLv3 or legacy Ciphers
    • use “o-saft.pl” for all protocols that are supported by your local computer
    • use “o-saft.pl +cipherall” (or “checkAllCiphers.pl”) to get the ciphers for the missing protocols, or recompile ‘Net::SSLeay’ and/or ‘‘openssl’’ to support more protocols and ciphers, see (Documentation INSTALLATION)[O-Saft/Documentation#INSTALLATION] for details
  • I can not use the latest features of the test (experimental) version
    • Please verify that you downloaded and unpacked the (‘master.zip’-Archive)[https://github.com/OWASP/O-Saft/archive/master.zip]
    • some new functions are protected by the option “–experimental”, please add it to your command (and take care what happens)
  • o-saft.pl seems to hang
    • try one or all of following options (see (Documentation Performance Problems)[O-Saft/Documentation#Performance_Problems])
      ”–no-dns”, “–no-http”, “–no-cert”, “–no-sni”, “–no-openssl”