Python Makefile
Latest commit 67173a1 Feb 17, 2017 @tomato42 committed on GitHub Merge pull request #112 from ep69/master
fixed specification of host to connect to

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Fuzzer and test suite for TLS (v1.0, v1.1, v1.2) implementations. Early alpha version - thus no API stability guarantees.


You'll need:

  • Python 2.6 or later or Python 3.2 or later
  • tlslite-ng 0.7.0-alpha3 or later (note that tlslite will not work and they conflict with eachother)
  • ecdsa python module (dependency of tlslite-ng, should get installed automatically with it)

Optionally, to make some calculations faster, you may want to install the following libraries (see tlslite-ng README for details):

  • m2crypto
  • pycrypto
  • gmp

To get pip (if your python installation doesn't already have it) download and run:


Then install tlslite-ng:

pip install --pre tlslite-ng

(Use --upgrade if you did install it before)

Download the tlsfuzzer:

git clone


After all dependencies are installed, make sure:

  • you're in the directory of the project (after git clone just cd tlsfuzzer)
  • the server you want to test is running on the same computer (localhost)
  • the server is listening on port 4433
  • and the server will answer with data to HTTP queries (answer with valid HTTP responses is optional)

Then you can just run one of the tests in scripts directory, as such:

PYTHONPATH=. python scripts/

If test has additional requirements, it will output them to console. No errors printed means that all expecations were met (so for tests with bad data the server rejected our messages).

Server under test configuration

In general, the server under test requires just a RSA certificate, you can create it using the following OpenSSL command:

openssl req -x509 -newkey rsa -keyout localhost.key -out localhost.crt -subj \
/CN=localhost -nodes -batch


To test OpenSSL, it's sufficient to pass an extra -www option to a typical s_server command line:

openssl s_server -key localhost.key -cert localhost.crt -www


To test GnuTLS server, you need to tell it to behave as an HTTP server and additionally, to not ask for client certificates:

gnutls-serv --http -p 4433 --x509keyfile localhost.key --x509certfile \
localhost.crt --disable-client-cert


To test the Mozilla NSS library server, you first need to create a database with server certificate:

mkdir nssdb
certutil -N -d sql:nssdb --empty-password
openssl pkcs12 -export -passout pass: -out localhost.p12 -inkey localhost.key \
-in localhost.crt -name localhost
pk12util -i localhost.p12 -d sql:nssdb -W ''

Finally, start the server with support for TLSv1.0 and later protocols, DHE ciphers and with the above certificate:

selfserv -d sql:./nssdb -p 4433 -V tls1.0: -H 1 -n localhost