SSL Audit - The SSL / TLS Scanner
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This document describes SSL Audit, a TLS/SSL scanner tool that scans web servers for SSL/TLS support. It can detect all known and RFC defined cipher suites without being limited to those supported by OpenSSL or NSS. The tool allows users to scan a host and port, see supported cipher suites, and experimentally fingerprint the SSL engine. It lists some known limitations and provides a changelog for version updates.
SSL Audit - The SSL / TLS Scanner
- 1. SSL Audit – TLS / SSL Scanner Thierry ZOLLER Thierry@zoller.lu http://www.g-sec.lu http://blog.zoller.lu G-SEC™ is a non-commercial and independent group of Information Security Specialists based in Luxembourg. Our work has been featured in New York Times, eWeek, ct', SAT1, Washington Post and at conferences ranging from Hack.lu to Cansecwest.
- 2. TLS/SSL Audit 2011 2 Table of Contents Table of Contents .............................................................................................................................2 About................................................................................................................................................3 Use....................................................................................................................................................3 Fingerprint (Experimental)...............................................................................................................4 Known limitations ............................................................................................................................5 Change log........................................................................................................................................5 Limitation of Liability........................................................................................................................5
- 3. TLS/SSL Audit 2011 3 About SSL Audit scans web servers for SSL/TLS support; it implements its own rudimentary SSL/TLS Parser and is as such not limited to ciphers supported by SSL engines such as OpenSSL or NSS and can detect all known and RFC defined cipher suites. Use Scan: Enter the host to be scanned and the appropriate port. Clear : Clears the results Option - Only display supported Cipher suites Experimental : Fingerprints the SSL engine (see “Fingerprint” Experimental) Cipher suites Host
- 4. TLS/SSL Audit 2011 4 Fingerprint (Experimental) Included is an experimental fingerprint engine that tries to determine the SSL Stack used server side. It does so by sending normal and malformed SSL packets that can be interpreted in different ways. It is able to distinguish IIS7.5 (Schannel) IIS7.0 (Schannel) IIS 6.0 (Schannel) Apache (Openssl) Apache (NSS) Certicom RSA BSAFE The higher the Score the more likely the host is using that engine. Note: SSL accelerators/load balancers will give unlikely results
- 5. TLS/SSL Audit 2011 5 Known limitations SSLv2 – SSLv2 detection is prone to false positives – Additional check whether the server accepts HTTP request after negotiations are required. This can be done manually: openssl s_client -ssl2 -connect SERVERNAME:443 GET / HTTP1.0 Some servers answer correctly to an SSLv2 handshake but will output a 500 status request when actually asking for a resource over HTTPS. SSL audit is currently not able to detect this. Fingerprints – This is a behavioral fingerprint - False positives are common especially in environments where SSL accelerator or load balancers are used Change log 0.8 Version Speed up SSLv2 discovery Added TLS 1.2 Camellia based cipher suites Added Aria based cipher suites (http://tools.ietf.org/html/draft-nsri-tls-aria-00) Alpha Version Added option to export results to CSV Updated documentation Limitation of Liability In no event and under no legal theory, whether in tort (including negligence), contract, or otherwise, unless required by applicable law (such as deliberate and grossly negligent acts), shall Thierry Zoller or G-SEC .ltd be liable to You for damages, including any direct, indirect, special, incidental, or consequential damages of any character arising as a result of this License or out of the use or inability to use the Work (including but not limited to damages for loss of goodwill, work stoppage, computer failure or malfunction, or any and all other commercial damages or losses),even if such Contributor has been advised of the possibility of such damages.