About SSLScan
SSLScan queries SSL/TLS services, such as HTTPS, in order to determine the ciphers that are supported. SSLScan is designed to be easy, lean and fast. The output includes prefered ciphers of the SSL service, the certificate and is in Text and XML formats.
Features:
* Highlight SSLv2 and SSLv3 ciphers in output.
* Highlight CBC ciphers on SSLv3 (POODLE).
* Highlight 3DES and RC4 ciphers in output.
* Highlight PFS+GCM ciphers as good in output.
* Highlight NULL (0 bit), weak (<40 bit) and medium (40 < n <= 56) ciphers in output.
* Highlight anonymous (ADH and AECDH) ciphers in output (purple).
* Hide certificate information by default (display with --get-certificate).
* Hide rejected ciphers by default (display with --failed).
* Added TLSv1.1 and TLSv1.2 support (merged from twwbond/sslscan).
* Compiles if OpenSSL does not support SSLv2 ciphers (merged from digineo/sslscan).
* Supports IPv6 hostnames (can be forced with --ipv6).
* Check for TLS compression (CRIME, disable with --no-compression).
* Disable cipher suite checking --no-ciphersuites.
* Disable coloured output --no-colour.
* Removed undocumented -p output option.
* Added check for OpenSSL HeartBleed (CVE-2014-0160, disable with --no-heartbleed).
* Flag certificates signed with MD5 or SHA-1, or with short (<2048 bit) RSA keys.
* Support scanning RDP servers with --rdp (credit skettler).
* Added option to specify socket timeout.
* Added option for static compilation (credit dmke).
* Added --sleep option to pause between requests.
* Disable output for anything than specified checks --no-preferred.
* Determine the list of CAs acceptable for client certificates --show-client-cas.
* Experimental build support on OSX (credit MikeSchroll).
* Flag some self-signed SSL certificates.
* Experimental Windows support (credit jtesta).
* Display EC curve names and DHE key lengths with OpenSSL >= 1.0.2 --no-cipher-details.
* Flag weak DHE keys with OpenSSL >= 1.0.2 --cipher-details.
* Flag expired certificates.
* Flag TLSv1.0 ciphers in output as weak.
* Experimental OSX support (static building only).
* Support for scanning PostgreSQL servers (credit nuxi).
* Check for TLS Fallback SCSV support.
* Added StartTLS support for LDAP --starttls-ldap.
* Added SNI support --sni-name (credit Ken).
* Support STARTTLS for MySQL (credit bk2017).
Building on Windows
Thanks to a patch by jtesta, SSLScan can now be compiled on Windows. This can either be done natively or by cross-compiling from Linux. See INSTALL for instructions.
Note that SSLScan was originally written for Linux, and has not been extensively tested on Windows. As such, the Windows version should be considered experimental.
Pre-build cross-compiled Windows binaries are available on the GitHub Releases Page.
OpenSSL issues: OpenSSL 1.1.0 Support
OpenSSL 1.1.0 introduced a number of significant changes, including the removal of old and insecure features such as SSLv2. While this is a very good thing for the SSL ecosystem as a whole, it is a problem for SSLScan, which relies on these legacy features being available in order to detect them on client system.
In order to work around this, SSLScan builds against Peter Mosmans' fork of OpenSSL, which backports the Chacha20 and Poly1305 ciphers to OpenSSL 1.0.2, while keeping the dangerous legacy features (such as SSLv2 and EXPORT ciphers) enabled.
TLSv1.3 and the future of SSLScan
Since the OpenSSL made the (very sensible) choice to remove support for legacy and insecure protocols and ciphers, SSLScan has relied on a fork of OpenSSL by Peter Mossmans which provided support for both these legacy ciphers and newly added ciphers (such as ChaCha). However, this fork of OpenSSL does not support TLSv1.3. To my knowledge there is no version of OpenSSL which supports both the legacy crypto (SSLv2, EXPORT ciphers, etc) and TLSv1.3 - which means that it is not possible to build SSLScan with support for both.
The primary goal of SSLScan is to identify misconfigurations and security weaknesses in the SSL configuration of a target system, so support for the legacy ciphers and protocols is much more important than for the newer (secure) protocols like TLSv1.3 - however over time this will change as new vulnerabilities are found.
Supporting both SSLv2 an TLSv1.3 in SSLScan would either require a fork of OpenSSL with all the new code backported (which would be increasingly difficult to maintain over time), or a complete rewrite of SSLScan to not rely on the OpenSSL library. This is not a project that I have the time available for at present, and if I did, it would probably be a better investment of time to work on one of the other SSL scanning tools, rather than starting from scratch.
As such, SSLScan should be considered legacy. I will still maintain it as far as I have time, but it is unlikely to ever support TLSv1.3, unless an OpenSSL fork is created by someone else that supports this while maintaining the insecure crypto that SSLScan requires to be useful.
Statically linking a custom OpenSSL build
It is possible to ignore the OpenSSL system installation and ship your own version. Although this results in a more resource-heavy SSLScan binary (file size, memory consumption, etc.), this allows to enable both SSLv2 and SSLv3 ciphers. In comparison to the method of repackaging the Debian build, this custom OpenSSL build won't affect other tools on the same system, as they would use the version packaged by the distro's maintainers.
To compile your own OpenSSL version, you'll probably need to install the OpenSSL build dependencies:
sudo apt-get install build-essential git zlib1g-dev
sudo apt-get build-dep openssl
then run: make static
which will clone the OpenSSL repository, and configure/compile/test OpenSSL prior to compiling SSLScan.
Please note: Out of the box, OpenSSL cannot compiled with clang without further customization (which is not done by the provided Makefile). For more information on this, see Modifying Build Settings in the OpenSSL wiki.
You can verify whether you have a statically linked OpenSSL version, if ./sslscan --version looks a bit like:
1.x.y-...-static
OpenSSL 1.0.2-chacha xx XXX xxxx
(pay attention to the -static suffix and the 1.0.2-chacha OpenSSL version).
Building on Kali Linux
Kali now ships with a statically built version of sslscan which supports SSLv2.
The package can be found in the Kali Git Repository.
If for whatever reason you can't install this package, follow the instructions above for statically building against OpenSSL.
Building on Debian
It is recommended that you statically build sslscan using the instructions listed above. If this is not an option and you want to compile your system OpenSSL with support for legacy protocols such as SSLv2 and SSLv3 then follow the instructions below.
Note that many modern distros (including Debian) ship with a version of OpenSSL that disables support for SSLv2 ciphers. If sslscan is compiled on one of these distros, it will not be able to detect SSLv2.
This issue can be resolved by rebuilding OpenSSL from source after removing the patch that disables SSLv2 support.
The build_openssl_debian.sh script automates this process for Debian systems. It has been tested on Debian Squeeze/Wheezy; it may work on other Debian based distros, but has not been tested. The built version of OpenSSL will be installed using dpkg.
If it is not possible to rebuild OpenSSL, sslscan will still compile (thanks to a patch from digineo/sslscan, based on the debian patch). However, a warning will be displayed in the output to notify the user that SSLv2 ciphers will not be detected.
